Light Metals 2024

With increasing amount of high silica bauxitesBauxite used as Bayer refinery feed, the re-precipitation of dissolved silicates results in greater volumes of desilication productDesilication products (commonly known as DSP) which corresponds to elevated caustic consumption and issues with bauxite residueBauxite residue neutralisationNeutralisation and storage. Furthermore, incomplete desilication of pregnant Bayer liquor also results in silicate reactor and piping scaling as well as the possibility of contamination of the aluminaAlumina product. Optimization of silicate management in the Bayer processBayer process is therefore a high priority. Understanding the chemistry of silicate leachingLeaching and precipitation of silicate in Bayer processBayer process underpins potential process improvements. This literature review summarises the chemistry of DSPs, with a focus on chemical-thermodynamics and reaction kinetics.

Low-temperatureLow temperature aluminaAlumina plants in Jamaica traditionally process hematiteHematite-rich ores with manageable concentrations of mineral impurities. As these ores become scarce, the new bauxiteBauxite mines have lower available aluminaAlumina, higher goethiteGoethite, and higher concentrations of phosphorus, chromium, and manganese contaminants. Since the minerals associated with some of the minor impurities have not been identified, this paper explores whether the contaminants accumulate in the coarse or fine bauxiteBauxite fractions. Samples of hematiteHematite-rich bauxiteBauxite from the traditional mining areas and also goethitic ores from the new mines were wet-sieved into three size fractionsSize fraction (+200, −200/+325, and −325 mesh). Each fraction was investigated using X-ray fluorescence (XRF)XRF and X-ray diffraction (XRD)XRD spectroscopies. Following digestion, their caustic soluble concentrations of phosphorus, chromium, and zinc were also determined. The traditional bauxitesBauxite had no correlation between size fractionSize fraction and the aluminaAlumina, ironIron, calcium, or phosphorus concentrations in the ore, however larger particles had slightly more manganese impurities. In contrast, larger particles from the new mines had higher concentrations of ironIron” and chromium impurities while smaller particles contained marginally more aluminaAlumina”. During digestion, the new bauxitesBauxite” gave higher caustic soluble P, Zn, and Cr and will be more challenging and costly to process into aluminaAlumina that meet the required specifications.

BauxiteBauxite digestion in the Bayer processBayer process results in a buildup of sodium carbonate in the caustic liquor, which reduces the efficiency of aluminaAlumina production. This effect is mitigated by limeLime causticisation, during which carbonate is removed, preferably as calcium carbonate. The extent and efficiency of causticisation in Bayer liquors are limited by the formationFormation of tricalcium aluminate (TCA) and alumino-carbonates, which also reduce overall plant productivityProductivity due to the consequent loss of aluminaAlumina from the liquor. We demonstrate that TCA formationFormation can be minimized or eliminated by using sugar-derived molecules, specifically gluconic acid, a mixture of gluconic and glucaric acids, and sodium gluconate. This reduction in TCA formationFormation improves the efficiency of causticisation by three to four times as determined by the rate constants for carbonate consumption or by the relative increase of C/S ratio. This in turn reduces aluminaAlumina and caustic losses in the causticiser, with the potential to improve the plant liquor C/S and hence the overall productivityProductivity of the Bayer circuit.

The global alumina refiningAlumina refining industry is under growing pressure to adopt eco-conscious practices and to achieve key sustainabilitySustainability goals. In addressing the energyEnergy-intensive nature of alumina refiningAlumina refining processes, it is vital to reduce the industry’s environmental impact. Hindalco has adopted a comprehensive strategy to promote energyEnergy-efficient practices for a greener future. The efforts and initiatives have resulted in reduced energyEnergy demand at the Renukoot refinery from 13 to 11.9 GJ/T, mainly through the use of process optimization techniques, data-driven insights, adaptive technologies, energy managementEnergy management practices, and waste heat recoveryWaste heat recovery methodsMethod. Collaborating with process engineers, industry experts, and management was crucial to monitor, analyse, and optimize operationsOperation. Apart from significant energyEnergy reduction, the initiatives led to enhanced economic viability and improved the sustainabilitySustainability credentials of the refinery. By setting a precedent, Hindalco Renukoot can inspire other refineries to follow suit, thereby fostering a more sustainable and eco-friendly alumina refiningAlumina refining industry.

AluminumAluminum plays a critical role in modern society, being a key commodity from electric vehicles to green buildings. Thus, decarbonizing the aluminaAlumina and aluminumAluminum industry allows the industry to extend the sustainabilitySustainability benefits to its downstream users by minimizing the associated Scope 3 emissions. Electrification of the aluminaAlumina industry can support the aluminaAlumina producers worldwide to reduce Scope 1 emissions by eliminating their reliance on fossil fuels. Switching to electricity provides the opportunities to capitalize on readily accessible renewable energyRenewable energy at most aluminaAlumina refineries. The absence of a direct heating source inside an electric calciner allows excess thermal energyEnergy in the form of high-purity steam from the aluminaAlumina processingProcessing to be efficiently recycled into the Bayer processBayer process for digestion and evaporation using mechanicalMechanical or thermal vapor recompression, improving the overall energyEnergy efficiency. Preliminary results from the study have shown no observable particle breakage, a common issue in traditional calcinationCalcination, which can help to improve the yieldYield and efficiency in Bayer circuit’s precipitation process and boost product quality. This study explores the potential capability of producing Smelter-Grade Alumina (SGA)Smelter-Grade Alumina (SGA) using an electric drop tube flash calciner as a feasible option to minimize its Scope 1 emissions and providing a potential pathway to zero emissions, aluminaAlumina, and aluminumAluminum production.

Large-scale circulating fluidized bedsCirculating fluidized bed are used as calciners in aluminaAlumina refineries. AluminaAlumina product quality (loss on ignition, LOI) depends on heat transferHeat transfer effects and particle residence time in the calciner. The operational parameters of fluidization such as air and fuel flow rates along with pressure drop across the furnaceFurnace are sensitive to changes in production rate. In this context, Lagrangian discrete phase model is used to simulate gas–solid hydrodynamics and visualize the thermal profile. The model is validated against the measured calciner temperature. SimulationsSimulation are performed for various flow rates of hydrate feed, air and fuel. The results revealed a strong influence of fluidization air flow rate and its split to primary and secondary air on the overall thermal profile. Therefore, an optimum ratio of primary-to-secondary air flow rate was deduced to achieve the desired thermal profile for varied production rates.

The aluminaAlumina calcining process takes place at high temperatures (up to 1100 °C) and, thus, the vessels are lined with refractory materials. Unexpected production halts or the extension of the maintenance time length have a relevant impact on the additional costs and unrealized revenue. Therefore, enhancing the refractories working life and its application speedSpeed is essential. Considering this, the objective of this work is to present the implemented improvements attained during the last few years, in terms of materials selection and quality controlQuality control, design and the gains in application time and return to operationsOperation. The achieved results indicated relevant gains regarding the reduction in the lining wear (and less unexpected halts) and speedSpeed up of the application steps (mainly the decrease of the drying/heat up curve). By following this approach, Hydro Alunorte maintenance area is increasing the reliability on the applied material, and contributing to more stable and long-lasting operationsOperation.

Through the emergence of inert anodesInert anodes and clean electricity, greenhouse gasGreenhouse gases emissions related to aluminum electrolysisAluminum electrolysis may fall substantially. However, this shift does not mitigate sustainabilitySustainability challenges in upstream mineral processingProcessing. Today, the Bayer processBayer process for aluminaAlumina production is identified as a major contributor to ecotoxicity, fossil fuel resource depletion, and ozone depletion in the aluminumAluminum supply chain. This process also generates 2 to 3 tonnes of highly alkaline bauxite residueBauxite residue, or “red mudRed mud”, per tonne of metal produced. Significant quantities of critical elements and ironIron are also lost to red mudRed mud. Alternative approaches that improve sustainabilitySustainability and byproduct recoveryRecovery in aluminaAlumina production are clearly needed. Herein, we demonstrate a new sulfur-based process chemistry for bauxiteBauxite refining, enabling the formationFormation of distinct aluminumAluminum-rich oxide and ironIron-rich sulfide phases in the mineral matrix. These phases are predicted to be amenable to physical separation, enabling the recoveryRecovery of ironIron and other materials as sulfides that historically have been lost to red mudRed mud generation. This novel approach may leverage existing solid–gas roasting reactors and comminution/physical separation equipment.

The Bayer processBayer process technologyProcess technology is widely used for the industrial production of aluminaAlumina, however, it is significantly impacted by two important defectsDefects: firstly, when using low-grade ore for production of aluminaAlumina the economics become very challenging, and secondly, the discharge of large volumes of alkaline red mudRed mud (bauxite residueBauxite residue) to the environment is highly undesirable. Based on the idea of redesigning the extraction phase of the process, a new methodMethod of producing aluminaAlumina by calcification transformation is proposed in this paper. The characteristics, advantages and disadvantages and economy of calcified carbonizationCalcified carbonization, calcified biomassCalcified biomass, calcified potassium alkaliCalcified potassium alkali and chlorinated alkali solutionChlorinated alkali solution are compared and analyzed. The feasibility of various calcified transformation red mudsRed mud are compared, and the progress of laboratory and industrial research on calcification transformation methodsMethod are analyzed comprehensively.

In contrast to the sintering methodSintering method for processingProcessing high-potassium aluminosilicateAluminosilicate raw materials, the product range for theHydro-garnet method hydro-garnet methodMethod, in addition to aluminium hydroxideAluminium hydroxide and potassium sulfate, also includes mono-calcium silicate. There are also no solid industrial waste products. Following a detailed technical and economic analysis of both processes, it is concluded that capital costs for the construction of production facilities and annual production costs in the case of theHydro-garnet method hydro-garnet methodMethod are much lower than with the sintering methodSintering method. Key investment indicators such as Earnings Before Interest, Taxes, Depreciation, Amortization (EBITDA), Earnings Before Interest And Taxes (EBIT), Internal Rate of Return (IRR), Net Present Value (NPV), and Profitability Index (PI) are better in the case of the hydro-chemical technology than for the sintering methodSintering method. This makes it possible to obtain a payback period for capital investments that is almost 1.7 times lower than in the case of using the sintering methodSintering method. Taking into account that with the sintering methodSintering method, direct emissions of carbon dioxideCarbon dioxide into the atmosphereAtmosphere are almost twice as high as with theHydro-garnet method hydro-garnet methodMethod, it is concluded that the sintering methodSintering method for processingProcessing high-potassium aluminosilicateAluminosilicate raw materials is economically less profitable and has more environmental hazards associated with it.

AluminaAlumina is produced commercially by the Bayer processBayer process, leading to tailings generation. For this reason, it is necessary to develop methodologies to remove the compounds that are not interesting, thereby producing liquors rich in aluminumAluminum and resulting in high-purity aluminaAlumina. This study aims to obtain high-purity aluminaHigh purity alumina from lateritic bauxiteBauxite through hydrometallurgical processes by leachingLeaching bauxites with both sulphuric and hydrochloric acids at varying concentrations, temperatures, solid/liquid ratios, and process times. The resulting acid extraction liquors were treated using solvent extraction processes that involved two types of extractants (D2EHPA and Alamine 336), varying pHs, kerosene/extractant ratios, and temperatures. The purified liquors were precipitated with ammonium hydroxide at pH 3 then the precipitatesPrecipitates were calcined at 1200 °C and analyzed by ICP-OES to verify transformation into aluminaAlumina and assess purity. The results showed that sulfuric acid extracted 100% of the ironIron and aluminumAluminum in the samples. In solvent extraction, Alamine 336 (pH = 0) and D2EHPA (pH -0.5) obtained an extraction rate of more than 90% for iron and less than 15% for aluminumAluminum. Following purificationPurification, 99.99% purity was achieved with D2EHPA.

The Bayer processBayer process is the primary technology utilized for aluminaAlumina production but it is limited by its stringent requirements on the quality of the bauxiteBauxite raw material. Due to the absence of a reasonable and effective large-scale utilization methodMethod, a substantial amount of high-alkali red mudRed mud generated from the process is kept in storage yards, occupying significant land space and posing grave threats to both the environment and human health. Based on prior research, this paper comprehensively summarizes and scrutinizes the current state of aluminaAlumina production as well as the management of red mudRed mud. Commencing with the phase structure of aluminaAlumina production, this paper delves into the development of the Bayer processBayer process and the Calcification-carbonization methodMethod. The aforementioned approaches offer pioneering concepts for promoting sustainable development within the aluminaAlumina industry.

This study presents a process for the simultaneous recoveryRecovery of metals from bauxite residueBauxite residue (BR) at relatively lower temperatures using H2 reduction to achieve zero-waste discharge (minimal waste generation) of BR. The proposed methodMethod involves blending BR with NaOH and subjecting it to H2 reduction (using different process parameters), resulting in an intermediate material enriched in magnetite and water-soluble aluminate. Optimal process parameters were determined (temperature of 600 °C, a reduction time of 120 min, 20 wt.% NaOH addition, and a reduction atmosphereAtmosphere of 5 vol.% H2 + 95 vol.% N2 with a 20 L/h flowrate), resulting in satisfactory recoveriesRecovery of Fe (74.7%, grade = 40%), Al (81.5%), and Na (91.4%). This approach represents a step towards the sustainable valorizationValorization of BR, i.e., the efficient recoveryRecovery of metals (Fe, Al, and Na) along with a non-magnetic fraction (Ca, Si, Ti, Rare earth elements), a precursor for further Sc, Ti recoveryRecovery, and an additive eventually for building materials.

Red mudRed mud is a bulk solid waste generated by the aluminaAlumina industry, which is difficult to use on a large scale due to its strong alkalinity. Meanwhile, carbon dioxideCarbon dioxide in flue gas is one of the main factors contributing to global warmingGlobal warming. Therefore, this paper employs flue gas carbon dioxideCarbon dioxide to neutralize the alkaline substances in red mudRed mud. The results showed that with the introduction of carbon dioxideCarbon dioxide into the red mudRed mud at 35 °C, a liquid-to-solid ratio of 10, and an aeration capacity of 20 L/h for 30 min, the dealkalinizationDealkalinization rate of red mudRed mud reached 33.12%. The reduction in alkalinity was due to the acid–alkali neutralization reaction of carbon dioxideCarbon dioxide with alkali compound in red mudRed mud. The carbon dioxideCarbon dioxide in the flue gas has a dealkalinizationDealkalinization effect on red mudRed mud, which can realize the dual purpose of red mudRed mud dealkalinizationDealkalinization and carbon dioxideCarbon dioxide neutralization.

In order to realize theHigh-iron red mud large-scale resourcefulness and harmless utilization of high-ironIron red mudRed mud, a pilot-scale experiment on vortex smelting reductionVortex smelting reduction of high-ironIron red mudRed mud was conducted using conditions determined on the basis of laboratory research. The pilot studyPilot study achieved good results. The ironIron recoveryRecovery was 97.12%, and a pig ironPig iron product containing 93.27 wt % ironIron was obtained. The experimental conditions included a temperature of 1500 °C, a carbon ratio of 1.3, a holding time of 30 min, a stirring speedSpeed of 125 rpm, an alkalinity of 1.0, and fluorite was used as a co-solvent at 10% of the calcium oxide addition. The concentrations of P and S in the pig ironPig iron were low, which allowed them to meet the requirements of the national standard L03 for steelmaking. The main phases in the reduction slag were gehlenite, calcium titanate, and nepheline, which were effective components for cement clinker production.

InAl-Si-Mg the past for current-conducting components copperCopper was primarily used. Due to high material price and limited availability of copperCopper, aluminumAluminum appears as a great alternative, especially since a higher weight-specific electrical conductivity is achievable and the lightweight construction is optimized. Excellent processingProcessing properties make this newest Al–Mg–Si alloyAlloys more than just a cheap alternative. Within the product development of the new 6xxx6xxx Al–Mg–Si alloyAlloys with high electric conductivity, the alloying elements and their solution state played key roles in reducing electrical resistance. Additionally, very good processingProcessing properties can be achieved, whereby the material required a specific strength and still has good bendability. During the production process, these properties were generated via a new solution heat treatmentHeat treatment approach and subsequent over-agingAging. Results showed the new aluminumAluminum grade achieves an electrical conductivity of 58%IACS (International Annealed CopperCopper Standard) and a crack-free 180° bend according to ASTM E290 (bending factor N = 1). Therefore, this aluminum alloyAluminum alloys is ideal for use as a bus barBus bar in EV batteries or other current-conducting applications such as EV charging stations.

In this study, four different compositions of high-strength 6xxx6xxx series aluminum alloysAluminum alloys with differentiation in the amount of their alloying elements (magnesiumMagnesium (Mg), silicon (Si), copperCopper (Cu), manganese (Mn), zinc (Zn), and zirconium (Zr)) were produced with direct chill castingDirect chill casting methodMethod as billetBillet form. After castingCasting process homogenizationHomogenization process was applied. Effects of the changes in chemical compositionChemical composition, homogenizationHomogenization time (3, 6, and 10 h), and temperature (525 °C and 545 °C) on solidificationSolidification behavior and microstructureMicrostructure were investigated. For structural characterizationsCharacterization of the samples, an optical microscope, energyEnergy-dispersive spectrometer-equipped scanning electron microscope, and for thermo-analytical studies, differential scanning calorimetry were utilized. Additionally, for thermodynamic modelingModeling and estimation of possible microstructural changes and solidificationSolidification behaviors of the alloysAlloys, JMatPro was used and outputs were compared with experimental results. Results showed that the microstructureMicrostructure, and cast properties of the high-strength 6xxx6xxx series aluminum alloysAluminum alloys were strongly affected by their chemical compositionChemical composition, homogenizationHomogenization time, and temperature.

The influence of feedrateFeedrate on the properties and microstructureMicrostructure of spin-formed aluminum alloyAluminum alloys 6061 is explored utilizing microhardnessMicrohardness mapping and microtextural analysis via electron backscatter diffraction (EBSD). The varying hardnessHardness profiles and microtexture are compared not only between samples spin-formed at various feedratesFeedrate, but through the thickness of the samples to understand microstructural gradients that could lead to mechanicalMechanical anisotropy and changes in formabilityFormability. The resulting hardnessHardness data show a clear gradient from the outer mold line to the inner mold line that varies with feedrateFeedrate and can relate to the imparted strain in the material. The microtextural mapping indicates a slight influence from feedrateFeedrate, but shows trends through the thickness of the material that suggests varying locationally dependent stress states. The results show for the first time the influences of spin formingSpin Forming on hardnessHardness and textureTexture that could be utilized to optimize spin formingSpin Forming processingProcessing parameters and mechanicalMechanical performance.

AluminumAluminum demand has dramatically increased as a result of the electrification of the automotiveAutomotive industry. Temperature has a significant impact on strength, especially in 6xxx6xxx series that can be strengthened through precipitation hardening and thermal stabilityThermal stability is regulated by copperCopper. However, copperCopper has a detrimental impact on corrosionCorrosion behavior. Therefore, it is important to determine the optimum copperCopper content in alloy designAlloy design. This study examines how the presence of copperCopper affects the 60826082 alloyAlloys’s thermal stabilityThermal stability and corrosionCorrosion behavior. AlloysAlloys with varying Cu contents were cast via DC castingDC Casting and subsequently subjected homogenizationHomogenization, extrusionExtrusion, and heat treatmentHeat treatment to achieve the T6 condition. To assess the specimens’ mechanicalMechanical characteristics and corrosionCorrosion resistance, tensile and corrosionCorrosion testing were carried out. Samples were analyzed using optical microscopy to understand microstructural characteristics and corrosionCorrosion mechanisms. This research provides valuable insight about 60826082 alloyAlloys that is widely employed in the automotiveAutomotive industry.

A stamped Al Alloy 6451Al Alloy 6451 containing 0.75 wt% Si used for outer panels of automotiveAutomotive body closures was tested for mechanicalMechanical performance by comparing uncorroded and corroded specimens subjected to immersion corrosionCorrosion following exposure to a 5.5 wt% NaCl saltwater solution. The mechanical propertiesMechanical properties including ultimate tensile strength (UTS), yieldYield strength (YS), and elongation (ef) were evaluated by tensile testing. Following the exposure to a 5.5 wt% NaCl saltwater solution, the stamped alloyAlloys 6451 exhibited a significant decrease of both its UTS and YS to 141.82 and 70.02 MPa from 161.54 and 86.82 MPa, by 12.2% and 19.4%, respectively. Similarly, the ef of the Al alloyAl alloys decreased to 14.62% from 16.23 by 9.9%. The microstructureMicrostructure observation indicated that the presence of corrosionCorrosion pits on the surfaceSurface of the corroded alloyAlloys might promote the crack initiation and growth.

FatigueFatigue failure remains a significant concern in engineering applications, especially in the aerospace and automotiveAutomotive industries where aluminum alloysAluminum alloys are widely used. Shot peeningShot peening is an attractive surfaceSurface treatment procedure to enhance the fatigue lifeFatigue life of materials. In this study, shot peeningShot peening at room temperature and 250 °C was performed at an Almen intensity of 0.20 mmA, on AA7010-T7452 aluminum alloyAluminum alloys fatigueFatigue specimens. The influence of the peening process on surface roughnessSurface roughness, hardnessHardness, and fatigue lifeFatigue life was investigated. Results showed that the average surface roughnessSurface roughness increased by 2.5 times and hardnessHardness increased by 4.6% as the temperature increased. TEM observations showed that the precipitation changed significantly during high-temperature shot peeningShot peening. High cycle fatigueFatigue tests revealed that HTSP at 250 °C decreased the fatigue lifeFatigue life of specimens by 2.6 times to 76% compared to specimens peened at room temperature. The decrease in fatigue lifeFatigue life of specimens peened at high temperature is due to the high surface roughnessSurface roughness.

X-ray computed tomography (XRCT)X-Ray Computed Tomography was used to characterize fractureFracture paths in AA7075-T6 sheet subjected to ductile tearingTearing at a warm temperature. Tear tests were conducted at 200 °C, and a pulling rate of 64 mm/min until the crack tipTips was approximately half way through the specimen. Three-dimensional XRCT data sets were acquired near each crack tipTips to map the crack, nearby porosity, and intermetallicIntermetallics particles. The XRCT data were analyzed using modern software techniques to segment out each of the important features. The spatial relationships between these features and their anisometry suggest microstructural causes for the anisotropy of tearingTearing resistance measured at warm temperatures; tearingTearing resistance is lower along the sheet rolling direction than it is along the long transverse direction. These connections are discussed, and methodsMethod for improving tearingTearing resistance are proposed.

This study explored the influence of magnetic fieldMagnetic field annealing in achieving enhanced mechanical propertiesMechanical properties in terms of yieldYield strength and microhardnessMicrohardness in 7075 aluminum alloyAluminum alloys. A custom-built 9 Tesla (T) superconducting magnetic system was employed during the agingAging of the samples at 120 °C without (0-T) and with (3-T) magnetic fieldMagnetic field to promote the precipitation and growth of strengthening phases. Mechanical propertiesMechanical properties measured with the aid of micromechanical tensile and Vickers hardnessHardness tests showed a 9% improved yieldYield strength and 12% increase in hardnessHardness with respect to increasing magnetic fieldMagnetic field strength to 3-T. The difference in the yieldYield strength for the 0-T and 3-T samples was then explained with yieldYield strength calculation models. This work thus reveals that applying magnetic fieldMagnetic field during the agingAging of 7xxx aluminum alloysAluminum alloys can help tailor and enhance the hardnessHardness and tensile properties of this alloyAlloys.

AluminumAluminum is by far the most produced non-ferrous metal. About one third of the annual aluminumAluminum production is generated by recyclingRecycling scrap. A stare scheme of alloyAlloys classifications, the difficult removal of foreign elements, and economic constraints in scrap sorting make the way of downcycling favorable. The product in this case is a secondary cast alloyAlloys. The main field of application for these alloysAlloys is in the internal combustionCombustion engine. The global trends toward electric vehicles will potentially shrink the demand for those alloysAlloys with a highly specificized field of application. Future scrapping of gasoline or diesel-powered end-of-life-vehicles (ELV) may lead to a surplus of scraps that cannot be recycled in a proper way as they already contain high amounts of foreign elements. This work investigates the direct potential of the two secondary cast alloysAlloys, EN-AC-46000 and EN-AC-46200. Both alloysAlloys were produced on laboratory scale, for their use as wroughtWrought alloysAlloys. The alloysAlloys were heat treated and successfully rolled to sheets. Tensile tests were performed in solution-annealed and artificial-aged condition. The results show an interesting combination of mechanical propertiesMechanical properties that may trigger further investigations towards an application of these alloysAlloys as sheet material.

TheSqueeze Die-cast present research focuses on the recyclingRecycling of various aluminium scrapsAluminium scrap that contain significant levels of silicon, ironIron, manganese, and copperCopper to create a new aluminium alloyAluminium alloys with superior properties. The alloyAlloys was designed to exhibit high extrudability and mechanical propertiesMechanical properties. The alloyAlloys was extruded at a low temperatureLow temperature of 430 °C, resulting in a good yieldYield and form free of extrusionExtrusion flaws. The produced alloyAlloys was characterized in three sets: Set 1 without agingAging (0 h), Set 2. with different agingAging times (3, 4, and 5 h) at 185 °C, and Set 3. with heat treatmentHeat treatment and different agingAging times (3 h., 4 h., and 5 h.). The mechanicalMechanical, electrical, and microstructural properties of each set were investigated. The samples in Set 1. had poor mechanical propertiesMechanical properties but high ductility due to the presence of Cu-enriched intermetallicIntermetallics as the dominant phase. Set 2 samples had the best mechanical propertiesMechanical properties while preserving high ductility, which was due to the synergy between α-Al (FeMn) Si, Cu-enriched intermetallicIntermetallics, spheroidal AlCuMgSi, and modified silicon particles. Set 3. samples underwent heat treatmentHeat treatment at an elevated temperature (530 °C for 3 h) with rapid quenching, then aged for varying times and quenched rapidly, this led to the dissolutionDissolution of the Cu-enriched intermetallicIntermetallics except for the AlMgCu phase with (Al96Mg3Cu1 and Al94Mg5Cu1, at. %), and the dominant phase was α-Al (FeMn) Si phase, which improved mechanicalMechanical characteristics. Overall, the ASH01 alloyAlloys produced in Set 2 conditions is a promising alloyAlloys with strong mechanicalMechanical characteristics and ductility as a recycled Al-scrap alloyAlloys.

The recyclingRecycling of 3xxx series alloysAlloys, often used to manufacture beverages, is undergoing the high demand to reduce energyEnergy consumption and carbon emission. A detailed understanding of the compositional effects (e.g., Mn, Fe, Si, etc.) on the mechanical propertiesMechanical properties is required due to the wide spectrum of alloyAlloys compositions received from the recycled alloysAlloys. We demonstrate a case study of using a newly established high-throughputHigh-throughput approach to establish the composition-property relationship of Al-Mn-Fe-Si-Cu alloysAlloys, involving combinatorial alloyAlloys synthesis by laser direct energyEnergy deposition (DED) additive manufacturingAdditive manufacturing (AM) and small-scale rolling. The study focuses on the effects of Mn and Si on precipitation and recrystallizationRecrystallization. The results reflected the similar behavior of DED alloysAlloys as DC-Cast counterparts in terms of microstructureMicrostructure and mechanical propertiesMechanical properties. This project suggests that the proposed methodMethod can support the material screening and phenomenological/mechanistic study for 3xxx series alloysAlloys.

It is necessary to find alternative feedstocks and consideration of production efficiency of aluminum alloysAluminum alloys yieldYield in substituting critical raw materials by increasing scrap content in liquid aluminumAluminum. The research focuses on evaluating the viability and efficiency of utilizing scrap materials as substitutes for critical raw materials specifically magnesiumMagnesium (Mg) and silicon (Si), in the production of 6xxx6xxx aluminum alloysAluminum alloys. According to the experimental set-up of this research comparisonComparison of recycled 60636063 and 60826082 alloysAlloys and the alloysAlloys produced with primary ingots with respect to chemical, metallographic, and mechanicalMechanical analyses has been conducted. The evaluation of the spectral analysis, optical microscopy images, tensile tests, and fractography analysis with SEM results in discussion of above-mentioned properties of the 60636063 and 60826082 alloysAlloys with different variants. Also, the extrusionExtrusion feasibility analysis of the alloysAlloys with increased recyclingRecycling ratio has been performed with QForm simulationSimulation software. The outcomes of this study will contribute to the development of environmentally friendly and economically reliable practices in the aluminumAluminum manufacturing industry.

In view of an upcoming scrap wave and the need for products with lower carbon footprintCarbon footprint, there is an urgent need to increase the recycled fraction inWrought aluminum alloys wrought aluminum alloys. However, due to the narrow compositional limits of conventional aluminumAluminum wroughtWrought alloysAlloys and the higher impurity levels in scrap material, the applicable recyclingRecycling content is limited. Therefore, new approaches need to be identified to increase the recycled content. The introduction of the AlMgZn(Cu) Crossover alloyCrossover alloys concept may prove to be a step forward in escaping the corset of conventional alloying systems. The 5/7-Crossover alloyCrossover alloys not only overcomes the long-standing trade-off between the excellent formabilityFormability of 5xxx-series alloysAlloys and the outstanding strength of 7xxx-series alloysAlloys by combining both properties but may also tolerate a higher content of impurity elements. The scope of this study is to properly address the 5/7-Crossover alloy’sCrossover alloys sustainabilitySustainability in terms of its ability to be manufactured from secondary raw materials. AlMgZn(Cu) alloysAlloys with different tramp element concentrations were investigated.

The production of Al alloysAl alloys from end-of-life (EoL) scrap is being accompanied by increased Fe-, Cu-, and Zn content. The influence of these elements was evaluated with special emphasis on phase formationPhase formation, via the application of CALPHAD methodsMethod to address the questions if a defined heat treatmentHeat treatment can compensate for the formationFormation of Al9Si2Fe2 and Al2Cu, how the combinations of such elements influence the formationFormation of detrimental phases and whether a combined approach of heat treatmentHeat treatment and alloy designAlloy design is valid for higher amounts of Fe, Cu, and Zn in primary-based alloysAlloys. It was found that Cu and Zn up to established limits in common supply specifications are less detrimental to alloyAlloys properties. Fe was found to be manageable, which is in good agreement with previous findings.

The world of aluminum alloysAluminum alloys is defined by alloyAlloys classification, which is usually based on the main constituent other than aluminumAluminum. This makes sense, as the basic material properties and their intended field of use follow accordingly. However, this standardization and classification not only limits the potential for improvement in the material property mix but also hinders the utilization of the ever-increasing secondary raw material streams. The AMAG CrossAlloy® family aims to overcome these obstacles through a unique alloy designAlloy design strategy that is not constrained by the usual limitations. The first member of this new alloyAlloys family—AMAG CrossAlloy®.57—has been successfully produced, characterized at AMAG’s facilities, and tested by selected customers in several potential fields of applications. This study provides a first insight into the results of these practical trials.

RecyclingRecycling Al-Si cast alloysAlloys with an increasing amount of contaminating elements are sensitive to the formationFormation of certain secondary phases, especially in the case of slow solidificationSolidification. This demands a profound understanding of typical recyclingRecycling impurity elements’ influence (e.g. Fe, Cu) on the resulting alloyAlloys’s microstructureMicrostructure and mechanical propertiesMechanical properties. In this work, the following questions were investigated and discussed for the alloyAlloys AlSi8ZnMn: Does CALPHAD calculation predict the presence of detrimental phases in the model recyclingRecycling cast alloyAlloys studied here? Do the mechanical propertiesMechanical properties deviate from primary-based alloysAlloys? Can the findings of the practical experiments be correlated with the CALPHAD results? It was found that Cu, very often mentioned as detrimental in cast alloyAlloys, can be used in a higher concentration range than expected while the influence of Fe turned out to be more crucial.

We characterize the microstructureMicrostructure and mechanical propertiesMechanical properties of cast Al-Ce-Ni-Mn-Sc-Zr alloysAlloys designed for structural use above 300 °C. We first report on the effect of Ni on the as-cast phase formationPhase formation, where all alloysAlloys consist of fine Al11Ce3 and Ni-rich eutectic phases, but the identity of the Ni-rich phase varies with Ni content. Furthermore, these alloysAlloys contain four coarsening-resistant strengthening phases as determined from SEM and APT investigations: (i) Al11Ce3 and (ii) Ni-rich micron-scale platelets formed during eutectic solidificationSolidification, (iii) L12-Al3(Sc,Zr) nanoprecipitates formed during secondary agingAging, and (iv) Mn solute in the α-Al matrix. The Al-Ce-Ni-Mn-Sc-Zr alloyAlloys possesses higher microhardnessMicrohardness and creep resistance than compositionally simpler alloysAlloys containing fewer of the strengthening phases, indicating that these strengthening mechanisms synergize to provide increased ambient- and elevated-temperature strength.

TitaniumTitanium is frequently used as a grain refinerGrain refiner in twin roll aluminum castingAluminum casting with its nucleation mechanism in aluminumAluminum. Grain refinementGrain refinement performance, castingCasting temperature, line speedSpeed, composition ratios of the grain refinerGrain refiner, additive amounts, kinetic factors, etc. vary depending on the parameters. In this study, the nucleation behavior between standard AlTi5B1 rods and in-situIn-Situ nucleantsNucleants was investigated. In this study, 1050 and 3003 alloyAlloys compositions were used because of seeing the behaviour of surfaceSurface, physical, and electrical properties. In the experimental studies, Reduced Pressure Test (RPT) analysis, microstructureMicrostructure measurements, and changes in mechanical propertiesMechanical properties were investigated. Experimental studies were examined according to changing time, titaniumTitanium amount, and castingCasting temperature. The surfaceSurface structure of the products after mechanicalMechanical deformation was compared with the visuals. After the relevant trials, comparisonsComparison of the standard modifiers and the in-situIn-Situ modifiers were done.

Solidifying aluminum alloysAluminum alloys, particularly metal matrix compositesMetal matrix composites (MMCs), present an ongoing challenge due to the inherent difficulty in achieving a uniform distribution of ceramic particles within the aluminumAluminum matrix. In this study, we investigate the anomalous phenomenon of particle banding that occurs during directional solidificationDirectional solidification (DS) of an Al-TiC-15wt%Zn composite fabricated through self-propagating high-temperatureHigh-temperature synthesis (SHS). This report presents results from scanning electron microscopy (SEM), allowing us to visualize stitched images along the growth direction of the sample and gain insights into the formationFormation of the banding morphology. Additionally, we initiate a qualitative discussion on the behavior of particles during directional solidificationDirectional solidification. Our findings suggest that an interplay between particle pushing and engulfment, contributes to this uncommon phenomenon. These results and discussions provide valuable insights into the manipulation of particle banding to achieve a targeted distribution of ceramic particles within the aluminumAluminum matrix. This advancement brings us closer to realizing a promising alternative for lightweight composite materials in the automotiveAutomotive and aerospace industries.

AluminumAluminum flat products are currently produced by twin-roll castingTwin Roll Casting and direct cooled castingCasting methodsMethod. Unlike the direct cooled castingCasting methodMethod, the solidification rateSolidification rate is quite high in theTwin-roll casting twin-roll castingCasting methodMethod. SurfaceSurface defectsDefects may occur due to production at high solidification ratesSolidification rate and metal feeding at high flow rates. In this study, the formationFormation mechanism of ripple trace, which is one of the surfaceSurface defectsDefects in theTwin-roll casting twin-roll castingCasting process, was investigated. The differences of the related defectDefects depending on the process parameters (alloyAlloys, castingCasting speedSpeed, metal level, temperature, etc.) in 15° inclined and horizontal twin-roll castingTwin Roll Casting lines were compared and reduced.

Shot peeningShot peening was employed to enhance the fatigueFatigue performance of aluminumAluminum A20X components manufactured by laser powder bed fusionLaser powder bed fusion (LPBF). The effect of shot peeningShot peening Almen intensity on surfaceSurface quality and fatigueFatigue properties of LPBF A20X were examined through surfaceSurface characterizationCharacterization and mechanicalMechanical testing techniques. Shot peeningShot peening improved surface roughnessSurface roughness and introduced compressive residual stresses, enhancing the fatigueFatigue performance by delaying crack initiation. The best fatigueFatigue performance was obtained at the highest Almen intensity (0.2 mmA), resulting in a 50% lower maximum valley depth (Rv) and a 156% improvement in fatigue lifeFatigue life compared to as-printed A20X.

Additive ManufacturingAdditive manufacturing (AM) is crucial for Industry 4.0Industry 4.0 where automation and real-time decision-making are to be performed with minimal human intervention. Most AM techniques involve meltingMelting metal powders layer-by-layer to build components which allows for complex geometries to be achieved; however, some challenges that inhibit it from becoming mainstream are hot cracking, porosity produced in the specimens, anisotropy and heterogeneity in the components with respect to the microstructureMicrostructure, mechanical propertiesMechanical properties, and crystallographic textureTexture. Such problems could be overcome if AM is performed without meltingMelting. In this regard, additive friction stir deposition (AFSD) exhibits the highest potential for industrialization. AFSD involves depositing a solid metal feedstock bar layer-by-layer while being heated by a rotating tool. In this work, the process, microstructureMicrostructure, crystallographic textureTexture, and hardnessHardness of Al 60826082 alloyAlloys after AFSD have been investigated. A fine-grained microstructureMicrostructure was obtained. However, there was a reduction in the hardnessHardness by 54%. This could be due to the precipitatePrecipitates coarsening and dissolutionDissolution during the processingProcessing.

AluminumAluminum thin-walled structuresThree-point bending are of great importance in the automotiveAutomotive industry, especially in electric vehicles. Thin-walled extruded components have been used by automotiveAutomotive designers, taking into account lightness considerations. Thin-walled components are generally used as structural components and are of great importance. Therefore, their mechanicalMechanical behavior should be well studied. In this study, an aluminumAluminum extruded thin-walled component was subjected to the three-point bendingThree-point bending testBending test. The obtained results were compared with the results of the finite element study. A hardening model was applied to simulate the mechanicalMechanical behavior of the test material. The findings suggest that the FE methodMethod provides an accurate prediction of the mechanicalMechanical behavior of the thin-walled structure and the FEA model can be a reliable tool to predict the behavior of similar structures in engineering applications.

Friction riveting (Fric-riveting) is an innovative, fast, and energy-efficient process for spot-joining metal–metal structures. Although fric-riveting has been studied experimentally in recent years, its process modeling is rarely found in the literature primarily because of the associated large material deformation, extreme thermomechanical conditions, and complex contact conditions. In this work, a meshfree smoothed particle hydrodynamics (SPH) framework that can handle the abovementioned numerical challenges is used to simulate the fric-riveting of AA5052 to AA6061. Predicted material morphology, multi-point temperatures, and plunge force are thoroughly validated by experimental observations. The material severe plastic deformation zone in the vicinity of the riveting zone is further predicted by the SPH model, which indicates the material mixing and potential grain refinement zone. Based on the validated model, process parameters can be optimized which yield better performance over the baseline case.

Emerging process limits in sheet metal forming of tailored blanks are determined by the mechanical propertiesMechanical properties of semi-finished sheet materials to be joined and the type of weld seam. The weld seam properties in turn depend on the welding tool material and the utilized process parameters. In this study, tailored blanks were produced made of aluminumAluminum AA6016 (2 mm) and the steel grade DX54 (1 mm) as well as from AA6016 (2 mm) and HX380 (1 mm) using different welding tool materials such as steel and ceramics. The joint between both blanks was performed as a butt joint or combined lap-/butt-joint. The formabilityFormability of the tailored blanks produced in this way was investigated using a three-point bendingThree-point bending device. The tests carried out were evaluated with regard to the maximum bending force. Best results were obtained for tailored blanks produced with ceramic welding tools producing a combined lap-/butt-joint.

The present study was performed on an Al-6% Cu-0.7%Si alloyAlloys, and 319 and 356 alloysAlloys following different heat treatmentsHeat treatment. The main task was to evaluate the drillingDrilling and tappingTapping characteristics of the Al-Cu alloyAlloys with respect to the Al-Si based 319 and 356 alloysAlloys. The drillingDrilling work was carried out on a Huron K2X8five CNC machine at 15,000 rpm with continuous cooling to absorb the heat and clean the holes from the chips formed during the drillingDrilling operationOperation. The results show that addition of Si coupled with T6 agingAging treatment produces the highest cutting forcesCutting forces (about 360N) among the alloysAlloys studied (approximately 270N) after 2500 holes. Considering the Al-Cu based alloysAlloys, varying the agingAging treatment has practically no significant bearing on the cutting forcesCutting forces. Apparently, a high Cu content acts as a self-lubricant, facilitating the drillingDrilling process up to 2700 holes, with no sign of tool wearTool wear. However, due to the low level of Si in the Al-Cu based alloyAlloys, built-up edge (BUEBUE) is more frequent, with conical chips, which would affect the precision of the size of the drilled hole. The chips are normally dull and characterized by their rough surfacesSurface compared to those obtained from A356A356.0 alloyAlloys.

CorrosionCorrosion is one of the most damaging and costly naturally occurring events seen today. There are several methodsMethod for predicting the corrosion rateCorrosion rate. In the present study, AA 5005AA 5005 cold-rolled sheet was used for welding application with AA5356AA5356 as filler materials using the MIGMIG welding process. Two different welding rates were applied for the weld joint of the cold-rolled AA 5005AA 5005 sheet. The TafelTafel extrapolationExtrapolation methodMethod and Nitric Acid Mass Lost Test (NAMLT) were used for the investigations of the corrosion ratesCorrosion rate. Analyses are done in Echem Analyst, and corrosionCorrosion products have been investigated via scanning electron microscope (SEM). At a higher welding rate, the result shows that corrosionCorrosion resistance is better than at a slower welding rate.

EN-AW-8006 isTwin-Roll Casting a common aluminum alloyAluminum alloys which is used in finstock and container foil applications. Therefore, corrosionCorrosion performance is an important criterion to fulfill the expectations of the service area. Alloying with numerous elements can be carried out to delay the onset of corrosionCorrosion and decrease the corrosion rateCorrosion rate in order to increase the product life and boost sustainabilitySustainability by securing the food stored in the container. In this study, EN-AW-8006 alloyAlloys strips with Mn and Cu additions were produced via Twin-Roll CastingTwin-Roll Casting (TRC) and rolled down to final thickness after homogenizationHomogenization in order to investigate the corrosionCorrosion behavior of the materials. It was concluded that alloying altered the size and distribution of intermetallicsIntermetallics which affected the response of the material against corrosionCorrosion, in return. Increase in the manganese was found to decrease the corrosion rateCorrosion rate, whereas copperCopper increased pitting formationFormation and promoted corrosionCorrosion.

The annealing behavior of cold rolling (CR) sheets of continuous castingContinuous Casting (CC) Al-1.5Cu alloyAlloys by using a tensile machine, optical and scanning electronic microscopes, and X-ray diffraction methodMethod was evaluated and studied overall. Compared with AA2024, Si and Fe amounts of the alloyAlloys were controlled at a low level; Mn and Mg amounts were controlled at a low limit of AA2024 alloyAlloys; Cu is selected at a low level (1.1–2.2%) due to the requirement of twin belt continuous cast processingContinuous cast processing. Compared to AA5xxx and AA3xxx alloysAlloys, material characteristic after annealing at different temperatures of cold rolling sheets of the Al-1.5Cu alloyAlloys are very different with some interesting special findings, such as the precipitation and solid solution of AlCu phase as well as P orientation ({011}<566>) textureTexture appearing, and so on. Annealing curves show a V shape with the annealing temperature increase. The findings would affect potentially and importantly subsequent processingProcessing (such as solid solution heat treatmentHeat treatment, quenching, forming, and agingAging) for application (replace AA5xxx-O sheet) to low-cost auto forming parts or sheets.

The microstructureMicrostructure of cold-rolled sheets is one of the important factors affecting the performance of battery aluminumAluminum foil products. The effects of wide-range annealing temperatures on the microstructureMicrostructure, textureTexture, and precipitatesPrecipitates of 1235D cold-rolled sheets were studied by theoretical calculation combined with experimental research. The results show that under the same annealing time conditions, as the annealing temperature increases from 360 to 560 °C, there is an optimal annealing temperature to obtain the minimum recrystallizationRecrystallization grain size, about 480 °C. The textureTexture strength shows a trend of first decreasing and then increasing with the increase of annealing temperature. Its essence is the disappearance of rolling textureTexture and the formationFormation of recrystallized textureTexture. The annealing temperature also significantly influences the conversion and size of the precipitatesPrecipitates in the cold-rolled sheets.

One of the areas where the AA6082 alloyAlloys is widely used is the production of forgingsForgings for automotiveAutomotive suspension parts. Round profiles produced by extrusionExtrusion from AA6082 alloyAlloys are semi-finished products for forged part manufacturers. EN AW 60826082 aluminumAluminum extrusionExtrusion production profiles with a diameter of 45 mm and a length of 100 mm were used for the hot forgingForgings process. According to the result, the measuring system reached a maximum temperature of 637 °C. The 2 °C difference between the oven temperature and the measuring system is acceptable. It was observed that there was a maximum difference of 5 °C between the core and surfaceSurface temperatures of this sample, which was heated in a resistance laboratory furnaceFurnace. However, in the induction system there is a difference of about 50 °C. The difference affected the structure and the hardnessHardness between the core and surfaceSurface of the forgingForgings parts.

In this study, the effects of homogenization heat treatmentHomogenization heat treatment and amount of cold rolling prior to intermediate soft annealing on the microstructural evolutionMicrostructural evolution and mechanical propertiesMechanical properties of cold rolled twin-roll cast EN AW-8026 aluminum alloy8026 aluminum alloy after soft annealing were investigated. For this purpose, homogenization heat treatmentHomogenization heat treatment was carried out on as-cast strips and after cold rolling with an equivalent strain of 1.15. Homogenized samples were cold rolled to the same strip thickness with two different equivalent strains and exposed to intermediate annealing. Annealed samples were cold rolled with an equivalent strain of 2.40 and soft annealed. Results show that homogenization heat treatmentHomogenization heat treatment leads to the formationFormation of equiaxed grain during intermediate annealing and final soft annealing. However, cold rolling prior to homogenization heat treatmentHomogenization heat treatment results in higher homogenizationHomogenization temperatures for the formationFormation of equiaxed grain during intermediate annealing and final soft annealing.

The effects of T6 and T7 heat treatmentsHeat treatment on the mechanical propertiesMechanical properties of a rheocast secondary AlSi7Cu3Mg alloyAlloys are investigated. A lower arm automotiveAutomotive suspension was cast as a demonstrator. While the solution treatment was optimized in previous research, the quenching rate and the ageing treatment were here studied. The influence of the quenching process on the component’s distortionDistortion was analysed by a coordinate-measuring technique. The results indicated a significant effect of the quenching rate on the tensile properties as well as the distortionDistortion of the component. Water quenching led to a greater distortionDistortion of the component compared to still-air cooling. The elongation to fractureFracture seemed to be less affected by the quenching process. Higher ductility was obtained after the over-ageing T7 treatment, while the yieldYield and tensile strengths were similar to those obtained after a peak ageing T6 treatment.

The A20X alloyAlloys, a metal matrix compositeMetal matrix composites (MMC) designed for laser powder bed fusionLaser powder bed fusion (LPBF), requires precipitation hardening treatment to achieve optimal mechanical propertiesMechanical properties. This study investigates the effect of temperature and duration of heat treatmentHeat treatment on the microstructureMicrostructure and mechanical propertiesMechanical properties of LPBF A20X. The effects of heat treatmentHeat treatment temperature and duration on the as-printed material were evaluated using mechanicalMechanical testing and microscopic characterizationCharacterization. In total, three different regimes reflecting the alloyAlloys’s response to heat treatmentHeat treatment were observed. For low-temperature (180–370 °C) heat treatmentsHeat treatment, material softening (up to 26%) proportional to temperature and duration of treatment was evident. Samples treated at medium temperatures (430–480 °C) showed hardening (from 90 up to 115 HV) with increasing temperature and remained unchanged with dwell time. This is attributed to the dissolutionDissolution of precipitatePrecipitates-formers (Cu/Mg/Ag) promoting solid solution strengthening. At high temperaturesHigh-temperature (≥500 °C), the alloyAlloys entered the super-saturation regime causing relatively constant hardnessHardness (~117 HV).

Aluminum alloysAluminum alloys produced by the twin-roll continuous castingContinuous Casting methodMethod are frequently used in construction, packaging, transportation, etc. areas of use. In this study, the effect of the products produced with different process types on the thermomechanicalThermomechanical and metallographic behaviors of the 1235, 3003, 8006, and 8011 alloyAlloys series, which are used in the packaging industry as foil products (crumpled container, household foil, flexible packaging, etc.), was investigated. Homogeneous annealing, intermediate annealing, and final annealing processes and their combinations were applied to the related alloysAlloys. Process differences are mentioned with microstructureMicrostructure (grain size distribution, centerline segregation) and mechanical propertiesMechanical properties (tensile test) analysis.

5182 is the most common 5xxx series aluminum alloyAluminum alloys for automotiveAutomotive applications. AutomotiveAutomotive manufacturers have set strict intergranular corrosionCorrosion resistance specifications for the specific alloyAlloys. The current paper presents corrosionCorrosion testing data (ASTM G67 Nitric Acid Mass Loss Test results) of 5182 alloy5182 alloy in fully soft O temper conditions produced by different cold rolling thickness reductions. CorrosionCorrosion testing is performed after low-temperatureLow temperature heat treatmentHeat treatment of O temper material (130 °C and 170 °C for soak time 17 h) to accelerate Mg precipitation along the grain boundaries. Increase of cold rolling thickness reduction before final O temper annealAnneal significantly reduces the corrosionCorrosion resistance of the alloyAlloys (increases the corrosionCorrosion test weight losses value). Fine grain size seems to reduce 5182 alloy5182 alloy O temper corrosionCorrosion resistance by increasing the corrosionCorrosion path length.

In the present work, aluminumAluminum–silicon (Al-Si) hypoeutectic alloysAlloys were studied in order to investigate the effect of solidificationSolidification parameters due to the addition of Si in the range of 6 wt. % to 9 wt. % on the structure characteristics and the microhardnessMicrohardness. The study was made by directional solidificationDirectional solidification methodMethod in a Brigdman-type furnaceFurnace. Different types of grains (columnar, equiaxed, and with columnar to equiaxed transition, CET) were visually observed. Such CET depended on the critical thermal gradient Gtc. The analyses carried out indicate that the secondary dendritic spacing (λ2) and the grain size increase significantly with the decrease in the cooling rateCooling rate (Ve). Furthermore, it was observed that the resulting microhardnessMicrohardness increases as the solidificationSolidification parameters (specifically Ve) increase, this is due to a refinement of the macro and microstructural parameters. Also, it was observed that the microhardnessMicrohardness increased with the increase of the Si content.

A qualitative mass balance for carbon dust and aluminium carbideAluminium carbide in aluminium electrolysis cellsAluminium electrolysis cells is suggested. The structure model by Ødegård et al. for dissolved aluminium carbideAluminium carbide in the bath was verified using formal activity data as well as an ideal Temkin activity model. The conditions for transport across the metal-bath interface (cathodeCathode) of carbon stemming from cathodeCathode wear were modelled. The main part of the current work consists of the derivation of a conceptual model for loss in current efficiencyCurrent efficiency (CE) caused by aluminium carbideAluminium carbide formationFormation by a reaction between carbon dust and dissolved metal close to the cathodeCathode. The reaction entails a steeper concentration gradient of dissolved metal and thereby increased loss in CE. The concentrations of dissolved metal, carbon particlesCarbon particles, and aluminium carbideAluminium carbide close to the cathodeCathode were calculated. The loss in CE was computed for different values of the reaction rate constant and the amount of carbon dust. It appeared that the loss in CE is probably limited by the kinetics of the chemical reaction since diffusionDiffusion control at small carbon particlesCarbon particles would produce an unrealistically high loss in CE.

Smelters worldwide face increasing challenges regarding power cost, flexibilityFlexibility requirements from power grids, and emission reductionEmission reduction from fossil-fuelled generation. Smelters can become responsible energyEnergy users by employing EnPot technology to proactively act as ‘batteries’ in power grids, to shed load and avoid coal/gas generation when renewables are insufficient, or take on extra load when excess power is available to increase production. The uncontrolled nature of cellCell heat loss has previously prohibited variable energyEnergy usage, however, EnPot can enable this with a complete heat balanceHeat balance of the cellCell. An analysis of typical heat loss distributions for 160 to 390 kA cellsCell justifies how significantly reduced/increased power operationOperation is achievable through control of cellCell heat losses. Further benefits of controlled heat loss are also described including benefits to cellCell control and life, as well as the uses of the waste heat collected.

Computational assessmentAssessment of magnetohydrodynamic stability in aluminum electrolysisAluminum electrolysis cellsCell is predicated on the availability of electromagnetic data of sufficient fidelity. While the currents within the fluid layers may be resolved considering only conductors local to the cellCell of interest, the other Lorentz interaction driver, the magnetic fieldMagnetic field, may be realizably influenced by conductors and magnetizable materials near and far. Quantification of acceptable domain extent is subject to the specifics of the operationOperation. Furthermore, simulationsSimulation must remain tractable in economically viable timeframes to be of engineering use, placing additional constraints on the extent of the modeled domain. This study seeks to elucidate the subjects of extent and fidelity concerning the cellCell technology at Alcoa’s Mosjøen smelter. Toward that goal, this effort explores the formulation and execution of electromagnetic simulationSimulation using the commercially available COMSOL Multiphysics. Domain truncation, as well as conductor and ferromagnetic component fidelity of neighboring cellsCell, are investigated.

The aluminumAluminum industry is moving toward intelligent and low-carbon development. Accurately predicting the anode effectAnode effect has always been a significant challenge in monitoring the aluminum electrolysisAluminum electrolysis process. However, due to the high-temperatureHigh-temperature and high-magnetic detection environment of aluminum electrolysisAluminum electrolysis cellCell, some critical parameters cannot be measured online. This inconsistency in data flow makes it challenging to apply traditional data-driven methodsMethod directly. In response to the characteristics of large data samples collected in actual production, we have proposed a multi-scale time series modelingModeling approach based on hybrid deep learningDeep learning. This methodMethod combines three advanced neural networkNeural networks models: BiLSTM, LSTM, and DNN. It enables the extraction of parameters that influence the anode effectsAnode effect from both short-term and long-term cyclic variables. Compared to traditional shallow machine learningMachine Learning (ML) methodsMethod, deep learningDeep learning methodsMethod, and hybrid learning methodsMethod, our proposed algorithm achieves the highest accuracy and F1 score, reaching 0.95 and 0.93, respectively. These results hold significant promise for reducing energyEnergy consumption and carbon emissions in actual production processes, paving the way for future applications.

Effective monitoring and precise control of electrolyte and liquidus temperatures (which together give superheatSuperheat levels) are imperative for optimising the performance, extending the lifespan, and improving the current efficiencyCurrent efficiency of aluminiumAluminium smelter cellsCell. During periods of intensive and frequent power modulationPower modulation, where the power input to the cellCell is altered, maintaining a perfect mass and thermal equilibrium becomes increasingly challenging. As a result, both bath temperature and superheatSuperheat will invariably fluctuate. This paper presents a study of a power modulationPower modulation event, as well as encouraging results on the use of a comprehensive dynamic model, which integrates mass and thermal balancesThermal balance, for the continuous prediction of the bulk electrolyte and liquidus temperatures, ledgeLedge thickness, and bath compositions. This paper is working towards addressing the absence of continuous thermal measurements suitable for real-time thermal monitoring and control, especially under complex conditions introduced by power modulationPower modulation.

The fourth industrial revolution, commonly referred to as Industry 4.0Industry 4.0, with smart manufacturing at its forefront has arrived. This work focuses on the deep integration of advanced digital twinDigital twins technology and traditional aluminium electrolysisAluminium electrolysis technology, involving the overall architecture design, core technological development, and demonstrative application study. A fiveFives-dimensional modelingModeling methodMethod and a standard application framework for aluminum electrolysisAluminum electrolysis are proposed for the first time. The constructed digital twinDigital twins of aluminium electrolysisAluminium electrolysis comprises three levels: electrolysisElectrolysis plant, workshop, and equipment, and is equipped with advanced functions such as real-time monitoringReal-time monitoring, data management, virtual-real mapping, and intelligent decision-making. The engineering applications of digital twinDigital twins technology in aluminium electrolysisAluminium electrolysis have demonstrated its efficacy, producing favourable results in terms of labour downsizing, energyEnergy conservation, and pollution reduction. This research is expected to establish a solid groundwork for the digitalization and intelligent advancement of aluminium electrolysisAluminium electrolysis.

The distribution of aluminaAlumina concentration is important for optimal cellCell operationsOperation in the aluminium smeltingAluminium smelting process. However, continuous real-time measurement of aluminaAlumina concentration is generally infeasible due to the hostile environment in the cellCell. As such a soft sensor is often needed to estimate the aluminaAlumina concentration from readily available measurements (e.g., cellCell voltage and line current). However, these approaches often suffer from poor estimation accuracy when the model error increases (e.g., during the anode effectAnode effect). To address these problems, this work develops a robust Kalman filter to estimate the spatial aluminaAlumina concentration using voltage measurements and individual anodeAnode current data. The proposed methodMethod utilises a Huber function to deal with model errors, resulting in more robust estimations. The effectiveness of this approach is validated through experimental data, demonstrating its potential for improving spatial aluminaAlumina concentration estimation in the aluminium smeltingAluminium smelting process.

A chemical model for the current efficiencyCurrent efficiency (CE) in aluminiumAluminium cellsCell was used for estimating the maximum attainable CE in industrial cellsCell. The model assumes that the loss in CE is governed by the mass transfer of dissolved metal from the metal surfaceSurface (cathodeCathode) to the bulk of the bath. The mass transfer-dependent effect of the NAF/AlF3 ratio at the cathodeCathode was included. The model implies that when the CE is plotted as a function of the mass transfer coefficient at the cathodeCathode, there will be a maximum in CE. For a high-productivityProductivity cellCell with a contemporary bath composition, the maximum appears to be about 96.5%. Some other factors that lower the current efficiencyCurrent efficiency are briefly discussed (too low anodeAnode-cathodeCathode distance, formationFormation of a layer of solid matter at the cathodeCathode (metal-bath interface), polyvalent impurity elements, cathodeCathode wear, carbon particlesCarbon particles, metal droplets, and small gas bubbles in the bath). A solid layer of cryolite and/or aluminaAlumina is not necessarily detrimental to the CE, at least if the surfaceSurface fraction is moderate.

Anode changesAnode change cause strong recurring disturbances of the Hall-Héroult process during smelter operationsOperation. Depending on its position, each anode changeAnode change triggers a specific redistribution of anodeAnode currents. This pushes the cellCell into a different magnetohydrodynamic regime with a changed metal/melt flow behavior and metal pad deformation. We have combined a magnetohydrodynamic modelMagnetohydrodynamic Model (MHD) based on computational fluid dynamicsComputational Fluid Dynamics (CFD) (MHD-CFD) with an equivalent electric circuit cellCell model (EECCM) to account for the dynamic coupling between magnetic fieldMagnetic field, metal/melt flow, metal pad shape, and anodeAnode current distributionCurrent distribution. The model integrates all dominant resistance contributions and allows cellCell voltage drop or anode–cathode distance (ACD) to be calibrated through simulated anodeAnode beam movements. Based on numerical results, cellCell responses from individual anodeAnode current changes and their effect on cell stabilityCell stability are evaluated. Predicted individual anodeAnode currents shortly before and after anodeAnode replacements are compared with measurement data and found to be in good agreement.

A new cathodeCathode liningCathode lining was developed and tested at Aditya aluminiumAluminium smelter to reduce the specific energyEnergy consumptionSpecific energy consumption. The copperCopper insertCopper insert in the collector bar was modified for uniform cathodeCathode current distributionCurrent distribution and lesser resistance. The uniform current distribution and lower resistance helped to reduce the overall cellCell voltage. The modified shape and size of the sidewall resulted in greater ledgeLedge thickness. Additionally, insulation bricks of lesser conductivity were used around the cathodeCathode. The thicker ledgeLedge and increased insulation maintain the desired cathodeCathode temperature at a lesser voltage. The process control parameters were modified to account for the increased bath mass. The standard operating procedure (SOPs) for pot relining, cathodeCathode preheatPreheat time, and start-upStart-Up parameters were modified to account for the increased pot cavity and lesser cathodeCathode resistance. Extra cooling arrangements were made to facilitate the quick build-up of the ledge at the sidewall during early cellCell life. The pilot pots have achieved reduced specific energyEnergy by ~150 DC-kWh/T.

Electrolysis cellsElectrolysis cell can be preheated electrically or by means of gas-fired systems, but the aluminiumAluminium industry prefers electrical preheatingPreheating with lying-bed due to economic aspects. PreheatingPreheating has a significant impact on early cellCell operationOperation and cellCell life since it goes through significant thermal, electrical, and mechanicalMechanical changes during this phase. Hence, successful preheatingPreheating is crucial for the smelter’s productivityProductivity. Thus, it is essential to determine the parameters for a good cellCell preheatingPreheating. In this work, the preheatingPreheating of an electrolysis cellElectrolysis cell for various lying-bed patternsLying-Bed Pattern is simulated using a strongly coupled, thermo-electrical ¼-cellCell model developed with ANSYS™ software. The thermal and electrical properties of the cokeCoke/graphite lying-bed are estimated by calibrating the model with in situ measurements and comparing the results in order to determine the better possible lying-bed patternLying-Bed Pattern in terms of key performance indicators, which define the quality of preheatingPreheating.

A reduced tapping cycleTapping cycle was proposed as an essential element to improve ALBRASALBRAS current efficiencyCurrent efficiency. Previously, metal tappingTapping was done every 48 h. A 32-h metal tapping cycleTapping cycle was evaluated, aiming to reduce liquid variation in the cellsCell and improve current efficiencyCurrent efficiency. The trial, together with improvements in operationOperation, proved a 2.03% CE increase, supported by better heat balanceHeat balance figures, reduced ledgeLedge variation, lower noise, fewer anode effectsAnode effect, a lower voltage per cellCell and ironIron content. Less ironIron also makes it possible to increase the production volume of PFA and P0610 alloysAlloys. This paper discusses the test development with respect to process and operational structure and the achieved results, which have guided ALBRASALBRAS discussions for its optimum operating mode for the coming years.

The financial crises affected many businesses in 2011, including those in the primary aluminumAluminum sector. Since then, industries have had to reinvent themselves to reduce costs and innovate waste reduction practices. This study analyzes the current state of gross consumption of anodesAnode at ALBRASALBRAS—Alumínio Brasileiro S.A. to systematize flows that help to reduce the consumption of anodeAnode pieces through the reuse of big buttsBig Butt of anodesAnode with a few days of consumption and the ability to replace a new one without contaminating the liquid metal with ironIron. Big buttsBig Butt’ use drives the reduction of the company's consumption of gross carbonGross carbon and commitment to be more sustainable and brings reductions in variable costs. The project started in November 2022 in a pilot line and was expanded to all lines in January 2023. Until June 2023, 669 pieces of big buttsBig Butt were reused, reducing around 2,85 kgC/tAl in gross carbonGross carbon consumption.

AluminiumAluminium smelters worldwide have been enticed by the idea of increasing amperage to boost overall production. Emirates Global AluminiumAluminium (EGA) has acquired extensive experience in ramping up amperage in various potlines. This article details EGA's experience and the challenges encountered during the amperage increaseAmperage increase in Al Taweelah (AT) Phase 1 potlines, which comprise two DX technologyDX Technology potlines: Potline 1 and Potline 2. The commissioning of the corresponding 756 pots was finalized in January 2011. Over time, the potlines underwent a gradual amperage increaseAmperage increase program, progressing from 350 to 437 kA. The article focuses on the latest phase of the amperage increaseAmperage increase program, specifically the transition from 420 to 437 kA, successfully completed in May 2023. It highlights the enablers that made the amperage increaseAmperage increase possible: rectifiers and busbar system capacity, the thermal balanceThermal balance of the pots, copper insertCopper insert collector bars, and extension of anodeAnode length.

In August 2021, AlbrasALBRAS needed to cut out a cellCell during an electric preheatingPreheating because of extreme variations in anodeAnode current and temperatures. This was the beginning of an analysis of the whole cellCell start-upStart-up process, from cellCell preparation until early operationEarly operation. Another motivation was the drop in pot life; more cellsCell were shut down before 1,000 days. As indicated in the literature, there are three main causes for premature failures: relining, startupStart-up, and early operationEarly operation. Our new understanding came from observing the behavior of cellsCell and having discussions with the Hydro Support team. After the shutdown of Potline 2 in 2022, this process was accelerated by the dedicated team that was responsible for restarting the potline. This paper describes how an operational procedure was developed that allows AlbrasALBRAS to reduce the average preheatingPreheating time from 80 to 60 h while achieving a high and uniform cathodeCathode temperature, increasing repeatability, and thus avoiding stresses at the beginning of cellCell life. The standardization has increased the performance of new and restarted cellsCell.

Emirates Global AluminiumAluminium (EGA) implemented a project to enhance metal tapping yokesMetal tapping yokes and trolleys’ design for safe handling and transportation. The modificationModification involved the removal of hydraulically equipped retractable platforms from trolleys’ decks and the introduction of a steel frame that is welded with tappingTapping yokes’ bail to support hook pin movement with a single steel handle mechanically attached to the frame. This mechanicalMechanical solution facilitates easy engagement and disengagement of the pot tending machine’s hook with the tappingTapping yoke from the working floor level. This improvement is a permanent and reliable solution with a simple design, eliminating the need to access elevated levels. The initiative eliminated safety risksSafety risks to operators when accessing elevated platforms, decreased maintenance costsMaintenance costs, and provided an efficient and cost-effective solution. This paper details the initial challenges, the ineffective hydraulic system, and the successful implementation of the mechanicalMechanical solution, which eliminated safety concerns and operational issues.

In 2022, Reduction Line 3 at Boyne Smelters Limited (BSL) underwent a process excursion that resulted in multiple cellsCell having to be cut out. As part of the recoveryRecovery process, a cellCell restartRestart methodology for the AP30 technology cellsCell was developed based on a survey of the different practices both within Rio Tinto AluminumAluminum and at other smelters. Subsequent trials of restarting several cellsCell in RL3 allowed for the development and refinement of the optimal methodMethod for cathodeCathode preparation, inspection, preheatPreheat, and stable early-life operationOperation. Out of the 24 cellsCell selected for possible restartRestart, 19 cellsCell were started successfully, 4 cellsCell were scrapped during inspection, and only one cellCell had to be cut out prematurely. The oldest cellCell started was 1489 days. The RL3 restartRestart project has been a great example of effective collaboration, resulting in a successful outcome for the BSL reduction, reconstruction, and technical teams.

This publication addresses a significant high carbon dust amountCarbon dust amount in aluminum electrolysisAluminum electrolysis with a high lithium potassium electrolyte. The wettabilityWettability of electricity on carbon materials and the influence of molecular ratiosMolecular ratio on carbon content in electrolyte melts were studied. Industrial tests were carried out, and the carbon dust amountsCarbon dust amount dropped significantly due to targeted measures. The results show that the wettabilityWettability of high lithium potassium electrolyte with carbon materials is better than that of pure electrolyte with low or no LiF and KF content. Generally, the carbon content and carbon dust in high lithium potassium electrolytes caused by domestic aluminaAlumina use are higher than those of pure electrolyte systems, but a reasonable range of molecular ratiosMolecular ratio could keep the carbon content below 0.2%. The key measures for reducing carbon dust in high lithium and high potassium systems follow the same rules for the wettabilityWettability of the electrolyte to the carbon materials.

China’s strategic goal of “Dual-Carbon” has put forward the requirements of “dual control of both energyEnergy consumption and intensity” for the aluminum smeltingAluminum smelting industry. Under these circumstances, Shenyang AluminumAluminum and MagnesiumMagnesium Engineering and Research Institute Co., Ltd. (SAMI) has carried out a series of technical research and upgrading projects since 2015. In 2022, Laibin Guangtou Yinhai AluminumAluminum Co., Ltd. implemented an upgrade project on their 330 kA potline using SAMI’s proprietary technology. This project involved adopting various technical strategies from SAMI, such as Networked Self-Equalizing Busbar Technology (NSBT), New Conceptual CathodeCathode Technology (NCCT), “Long Healthy Life”\“Long Healthy Life\” pot lining designPot lining design, etc. The current of this potline was increased to 350 kA, and the energyEnergy consumption of liquid primary aluminumAluminum was reduced to 12,520 kWh/t-Al from 13,182 kWh/t-Al. These technologies offer strong technical support for the existing aluminum smeltersAluminum smelter to upgrade their current low-amperage reduction cellsCell, leading to lower carbon emissions.

EGA is working to improve the accuracy of process control and process prediction through the adoption of 4.0 technologies. There are 2843 pots across the two EGA sites. Accurate prediction of pot failures is needed to optimize resources and workforce allocation. The model also helps in achieving the target pot life considering various factors of different EGA technologies with kA values ranging from 230 to 465 kA, construction materials, operating parameters, and current failure control measures. In this paper, we will further discuss how the cost of operating with aged pots can be linked to that of replacing them with new pots. This is an interactive dashboard where the shop floor can provide the system with details of the actions taken to improve the forecast day by day.

Pot tending machines (PTM) play a vital role in supporting the aluminium reductionAluminium reduction process. The intelligent monitoring system SMARTCrane allows real-time monitoringReal-time monitoring of key equipment parameters and compliance with predefined operationOperation sequences, thus ensuring optimal and repeatable production. This intelligent monitoring system, thanks to its ability to operate precisely and instantaneously, contributes to a significant decrease in performance variations and improves the stability of operationsOperation. With SMARTCrane, operationsOperation can maintain high repeatability in their jobs, reducing performance fluctuations and minimizing production losses, and maintenance can improve efficiency by anticipating their activities. Real-time collected data and predictive models enable proactive monitoring and continuous optimization of pot parameters. SMARTCrane is a result of close cooperation between aluminiumAluminium producers and FivesFives engineers. Utilizing the equipment knowledge among FivesFives engineers, on specific crane features such as lifting devices, compressors, or insulation monitoring devices, the system can process the data and issue automatic alerts. In this paper we focus on SMARTCrane used on PTM, however, FivesFives deployed it also on FurnaceFurnace Tending Assemblies (FTA). In conclusion, SMARTCrane offers an innovative approach to improve the efficiency and stability of aluminiumAluminium production operationsOperation.

In aluminium electrolysis cellAluminium electrolysis cells, thermal balanceThermal balance represents a very sensitive aspect of process control and its optimization. This balance is strongly influenced by the side ledgeLedge behaviour, making it crucial for cellCell performance. Despite the existence of numerous studies on ledgeLedge, its precise behaviour remains difficult to assess in a timely manner due to the aggressive environment and the limited access to the ledgeLedge. The literature reports only limited methodologies to quantify the formationFormation of ledgeLedge in the electrolysis cellElectrolysis cell, and these are generally only representative of a short period. In this article, the challenges associated to ledgeLedge measurement and controls are discussed along with the relevant parameters and thermal events. Solutions proposed to manage these limitations are discussed including numerical and physical methodsMethod.

The electrolytic cellCell control systems, designed on the basis of cellCell voltage and line current, are becoming increasingly unsuitable for large aluminumAluminum electrolytic cellsCell. Instead, the design of the next generation electrolytic cellCell should be based on the anodeAnode. The accurate measurement of anodeAnode current is available by use of the fiber optic current sensor (FOCS). The employment of FOCS in aluminum reductionAluminum reduction cellsCell could be considered as a disruptive technological application. The measurement principle of FOCS is first introduced, and then the methodsMethod for online measurement of anodeAnode current in the aluminum reductionAluminum reduction cellCell are presented. The results showed that, FOCS could be used to provide a series of effective methodsMethod for achieving the digital, intelligent, and refined control of the aluminum reductionAluminum reduction cellCell based on the measurement results.

Using metallic anodesAnode enables oxygen evolution during the aluminum reductionAluminum reduction in electrolysis cellsElectrolysis cell with vertical electrodes. Although they are considered non-consumable compared to carbon ones, they tend to corrode in molten fluorideMolten fluoride media, and the corrosionCorrosion products end up in aluminumAluminum as impurities. The big challenge for the industry is finding the best conditions (anodeAnode and bath composition, temperature, and current density) that provide the lowest corrosion rateCorrosion rate. The most reliable way to characterize the corrosion rateCorrosion rate is to perform an electrolysisElectrolysis test and determine the mass of anodeAnode components in the produced aluminumAluminum. This methodMethod is highly time- and resource-demanding. This paper investigates the connection between the electrochemical parameters of the anodeAnode process, which can be measured in minutes, and the results of long-term electrolysisElectrolysis tests. Several parameters, such as exchange currentExchange current density on clean and oxidized surfacesSurface, were studied in the low-temperature KF-NaF-AlF3-Al2O3 melt at 800 °C. A linear dependency between exchange currentsExchange current and corrosion rateCorrosion rate was found.

This study reportsAluminum the directAlloys production of aluminum–manganese alloysAluminum–manganese alloys during the electrodeposition of aluminumAluminum in cryolitic melts. For the purpose of measuring current efficiencyCurrent efficiency, experiments were conducted in a laboratory cellCell. The temperature was changed between 960 and 980 °C at a cryolite ratio (CR) of 2.2 and a cathodic current density (CCD) of 0.9 A/cm2. Up to 3.0 weight percent of manganese was present. Mn2O3 was used as a methodMethod of manganese addition. To track the dissolutionDissolution of manganese during electrolysisElectrolysis, bath samples were routinely taken, and ICP-MS was examined. Al-Mn alloyAlloys electrodeposition current efficiencyCurrent efficiency was estimated to be in the region of above 90%. Estimates of aluminumAluminum's current efficiencyCurrent efficiency were made. The metal deposits’Deposits' hardened surfacesSurface were essentially flat, but some were deformed.

AluminumAluminum–scandiumScandium master alloysMaster alloy are highly demanded products used to create multi-functional aluminum alloysAluminum alloys and composites. A high cost of Al-Sc master alloysMaster alloy stops the automotiveAutomotive industry from using them widely. This research investigates the possibility to produce Al-ScAl-Sc master alloysMaster alloy via electrolysisElectrolysis of the LiF-AlF3-Sc2O3 melt. The kinetic parameters of the aluminumAluminum and scandiumScandium electrowinningElectrowinning were studied by means of voltammetryVoltammetry, stationary polarization, and electrolysisElectrolysis tests. The apparent limiting current density for co-deposition of AluminumAluminum and ScandiumScandium on tungsten cathodeCathode was in the range from 1.28 to 1.97 A.cm–2 in the temperature range from 860 to 940 °C. Based on the electrochemical measurements, the parameters for galvanostatic electrolysisElectrolysis were selected and electrolysisElectrolysis tests were carried out to obtain Al-Sc master alloysMaster alloy. The microstructureMicrostructure of the obtained Al-Sc master alloysMaster alloy was studied. It was possible to obtain Al-Sc alloysAl-Sc alloys with the concentration of Sc 0.68 wt.%.

There is a strong push towards developing an alternative low-carbon process for the primary production of aluminiumAluminium. ElectrolysisElectrolysis with inert, oxygen-evolving anodesAnode is an attractive alternative, and alloysAlloys of Ni–Fe–Cu are promising. This paper describes results from electrochemical studies to examine the performance of such anodesAnode for different sodium–potassium cryolite electrolyte compositions from CR = (NaF + KF)/AlF3 = 1.3 to 1.4, and KR = KF/(KF + NaF) = 0.3–0.4. VoltammetryVoltammetry curves reveal how surfaceSurface treatment in the form of anodeAnode pre-oxidation reduces passivation current and improves anodeAnode stability. Also, the effect of the polarization history of the anodeAnode on the voltammetryVoltammetry characteristics and the overall long-term stability of the anodeAnode is addressed, but leaving the anodesAnode unpolarized in the electrolyte damages the dense, protective oxide layer on the anodeAnode surfaceSurface, although pre-oxidation offersOxygen-evolving electrodes some protection.

With increasing concerns about environmental performance and workplace security, the production of primary aluminumAluminum encounters many challenges. Among them is the introduction, dissolutionDissolution, and distribution of large quantities of aluminaAlumina into a small volume of electrolyte with a large horizontal surfaceSurface using only a limited number of discrete injection points. Typically, one kilogram of aluminaAlumina is injected at each location every minute or so, which agglomerates and creates rafts limiting the dissolutionDissolution rate. More importantly, to prevent instability, the rafts must disappear from the rafts injection point before the next addition, either as a result of dissolutionDissolution, transport, or disintegration. The work presented uses a dimensional analysis to quantify the dissolutionDissolution and disintegration rate of aluminaAlumina raft. A theoretical approach is proposed to understand the key behaviors observed from extensive experimental work on the dissolutionDissolution of different macroscopic forms of aluminaAlumina. Finally, the potential application of the model proposed is also presented.

Primary aluminiumPrimary aluminium producers are inclined to maximize the cellsCell’ current efficiencyCurrent efficiency in order to enhance metal production and reduce production cost. For timely decisions, sodium contentSodium content of the cathodic aluminiumAluminium has been used as a performance indicator related to individual cellCell performances. This paper pinpoints the straightforward quantitative theoretical relation which exists between sodium contentSodium content and current efficiencyCurrent efficiency. This relation is based on the fundamental thermodynamics of the changing bath composition in the boundary layers and on mass transfers at the anodic and cathodic interfaces. Few simplifying hypotheses are used to predict the cellCell’s optimal current efficiencyCurrent efficiency under a specific set of operating conditions. The proposed calculation methodology is described and a critical discussion is performed to highlight the impact of different factors on the current efficiencyCurrent efficiency along with future considerations necessary to improve the current efficiencyCurrent efficiency estimations.

The global aluminiumAluminium industry is trying to reduce its carbon footprintCarbon footprint, in line with climateClimate change policy, and great strides are being made in the use of hydropower, solar, and geothermal electricity, as opposed to fossil-fuel powered electricity. Two major smelting challenges remain however: finding inert anodesInert anodes and wettable cathodesWettable cathodes. VSCA, a EuropeanEuropean materials company, has invented and developed two promising solutions: (1) A nickel-based anodeAnode alloyAlloys that has been successfully tested for over a week at 960 °C in a Hall-Héroult cellCell with limited corrosionCorrosion or passivation; (2) A wettable TiB2 cathodeCathode that has survived over 3 months of continuous exposure to liquid aluminiumAluminium, again at 960 °C, without any signs of degradationDegradation or dissolutionDissolution. Combining an inert anodeInert anodes with a wettable cathodeWettable cathodes is considered to be the ‘holy grail’ of aluminium electrolysisAluminium electrolysis. This paper shows that green aluminiumAluminium with near-zero CO2 is within grasp and could be realized with further testing and industrial scale-up.

Reliable monitoring of oxide concentrations in electrowinningElectrowinning of metals in fluoride-based electrolytes is very important for avoiding unwanted reactions, notably perfluorocarbonsPerfluorocarbons emissions which are very potent greenhouse gasesGreenhouse gases. A probe, consisting of a working electrode and a counter electrode, has been developed for online monitoringOnline monitoring of metal oxide concentrations in molten fluoride electrolytesMolten fluoride electrolyte. During measurements, the immersed probe in the electrolyte is subject to fast anodic polarisation sweeps while the electric current response is recorded. During anodic polarisation, oxide species in the electrolyte are rapidly depleted at the probe, resulting in a response called anode effectAnode effect on the probe tipTips, triggering a rapid voltage increase and current drop. The rate of oxide depletion and the consequent anode effectAnode effect is proportional to the dissolved oxide concentration. This allows to correlate voltage-current–time curves to the oxide concentration. Measurements in cryolite melts with different oxide concentrations showed different voltages at which anode effectAnode effect occurs.

Hall-Héroult (in smelting plant) has been the key process for aluminumAluminum production since 1886, and it has gone through several improvements in the past. However, challenges like low efficiency, premature cellCell failure, and sustainabilitySustainability-related issues persist even today and the industry is working to overcome them. Industries have significantly benefited by adopting the fourth industrial revolution (I4.0) concepts such as digital twinDigital twins, remote monitoring, predictive maintenance, data & analytics, etc. They have helped industries to achieve their objectives. The same concepts will also help aluminumAluminum industry to address their challenges. This paper describes specific challenges related to aluminumAluminum production and defines a roadmap for adopting I4.0 concepts to help solve problems. This paper introduces a structured approach for the digital transformationDigital transformation of complex smelting plants and recommends a roadmap for this industry.

On the lining of the aluminum reductionAluminum reduction cellsCell, layers of refractories are used to ensure proper thermal equilibrium as well as the protection of the insulating bricks underneath from high temperaturesHigh-temperature and chemical attacks. These materials, which largely affect the cellCell's life, are subject to corrosionCorrosion by the electrolyte bath. In this paper, the breakdowns and/or the degradationDegradation of the ordinary refractory bricksOrdinary refractory bricks (ORBs) located on the sidewalls and below the cathodeCathode blocks are investigated during industrial autopsiesAutopsies performed after cellCell failure or scheduled shutdowns. Subsequent chemical characterizationCharacterization on the ORBs was carried out using Scanning electron microscopy with energyEnergy dispersive X-ray spectroscopy (SEM–EDX), X-ray fluorescence (XRF)XRF, X-ray powder diffraction (XRD)XRD, and Differential scanning calorimetry (DSC) analysis. The XRD results indicate that nepheline, cryolite, and silicon are present in both sidewall and bottom ORBs with higher presence of sodium fluoride phase in bottom ORBs. Comprehensive literature review is also conducted based on the degradationDegradation of ORBs and compared to the results obtained during industrial autopsiesAutopsies. Subsequently, ORBs samples will be exposed to electrolytic bath contamination at different temperatures and durations at the laboratory scale. The aim is to examine the contamination history endured by ORBs in an aluminum reductionAluminum reduction cellCell.

AluminiumAluminium is an essential metal to a number of technologies critical to the energyEnergy transition. Therefore, its production capacity has been continuously growing for decades. And so is the interest in its production carbon footprintCarbon footprint, for both primary and secondary (recycled) materials. CathodeCathode blocks used for primary aluminiumPrimary aluminium smeltingAluminium smelting are carbon-rich fossil-based products that require energyEnergy-intensive processes for their manufacturing, especially for graphitized cathodesGraphitized cathode that are now becoming the new mainstream technology. It is therefore essential to evaluate the graphitized cathodeGraphitized cathode production impact on climateClimate change. In this paper, for the first time, a complete “cradle-to-gate” carbon footprintCarbon footprint assessmentAssessment, using the ISO 14 067 as guidelines, dedicated to the graphitized cathodeGraphitized cathode (G-CA) product is performed, based on Tokai COBEX French manufacturing operationsOperation. The results evidence that the production of calcined petroleum cokePetroleum coke (main raw material), the block baking and graphitization treatments account together for the majority of the 4.1 kgCO2eq./kgG–CA emitted during the graphitized cathodeGraphitized cathode production. Major contributor types during the baking and the graphitization processes are the energyEnergy consumption (natural gas especially, used during baking) and the volatiles released during the heat treatmentsHeat treatment. Finally, a sensitivity analysis is performed by parametrization of the calcined petroleum cokePetroleum coke and the electricity carbon footprintCarbon footprint, showing variations of −20% (low-carbon cokeCoke) to + 101% (hard-coal fired electricity).

In aluminumAluminum production, the use of carbon anodesCarbon anode leads to the sulfur dioxideSulfur dioxide emissions which have adverse effects on health and environment. In this work, hydrated limeLime Ca(OH)2 was used to remove the low concentration of SO2 gas through a semi-dry desulfurizationDesulfurization process. The reaction was carried out under dry and humid conditions, and the reaction at low temperatureLow temperature was studied. The results indicated that the humidity plays a key role in the reaction between hydrated limeLime and SO2. The morphological analysis and surfaceSurface area results showed that the limeLime samples have significant changes in their topological and surfaceSurface properties, which influences the amount of SO2 capture. The X-ray photoelectron spectroscopy results complement those of the chemical changes due to the influence of low reaction temperature on the surfaceSurface of hydrated limeLime. In this article, the results are presented which demonstrate the impact of various factors at low temperatureLow temperature.

AsPot Integrated Abart (PIA) most electrolysisElectrolysis pots in an aluminiumAluminium potline will have different rates of fluoride lossesFluoride loss, while the secondary aluminaAlumina from the GTCGas Treatment Centre (GTC) will contain an average fluorine content an imbalance will occur over time leading to instability and require corrections by additions of fluoride or removal of excess bath. The development of the Pot Integrated Abart (PIA) technology from REEL will address this issue by having dedicated dry scrubbers for each pot. A research PIAPot Integrated Abart (PIA) unit has currently been built and testing was started at Alcoa Mosjøen in Q4 2022. The results and findings from the early stages of operationsOperation will be discussed, as well as direct impacts on measurable cellCell parameters. Further, the results will be used as input for predictions on how cell stabilityCell stability and operationsOperation in the potroom is affected by the introduction of the PIAPot Integrated Abart (PIA).

The centre for an energyEnergy efficient and competitive industry for the future (HighEFF) at SINTEF has over 7 years considered different aluminiumAluminium production technologies with focus on energyEnergy consumption and environmental footprint. Primary aluminiumPrimary aluminium production technologies including the Hall-Héroult processHall-Héroult process, inert anodeInert anodes, and the chloride processChloride process were considered. The investigations suggest that inert anodeInert anodes technology and the chloride processChloride process will curtail emission of greenhouse gasesGreenhouse gases, provided the electrical energyEnergy source is renewable. Inert anodesInert anodes will eliminate CO2 and perfluorocarbonPerfluorocarbons emissions but will require more energyEnergy due to the absence of carbon anodesCarbon anode. The chloride processChloride process has the lowest electrical energyEnergy consumption and may be more environmentally sustainable, provided that the carbon is recycled or based on biomass. The Hall-Héroult processHall-Héroult process has the potential to be climateClimate neutral by incorporating carbon capture and storage. It is noteworthy that more than 60% of CO2 emissions is related to the power production.

Recent cellCell designs tend to use innovative sensors coupled with control systems for timely process decisions that provide a common usage of digital twinsDigital twins and improved competitiveness. As the cellsCell are pushed closer to their operational limits, the preservation of the energyEnergy balance is a dominant limitation in the aluminumAluminum industry. Consequently, the proper use of novel measurement procedures and sensors is a realistic path toward optimal conditions. In order to understand the key drivers, and to pinpoint possible solutions, this article investigates the heat and energyEnergy balance of the cellCell with its main focus on the sustainabilitySustainability of proper alumina dissolutionAlumina dissolution conditions. The paper highlights the difficulties associated with different process operationsOperation resulting in heat and thermal imbalance. Finally, solutions that can provide smelters with efficient ways to mitigate these disruptions are presented and discussed that improve energyEnergy efficiency and reduce greenhouse gasGreenhouse gases emissions.

In the context of the dual carbon strategy, efficient recyclingRecycling and utilization of waste heat from aluminum electrolysisAluminum electrolysis cellsCell is one of the implementation paths for the aluminum electrolysisAluminum electrolysis industry to achieve deep energyEnergy conservation and carbon reduction. In response to the technical bottleneck problem of difficult recoveryRecovery of waste heat on the side of aluminumAluminum electrolytic cellsCell, a dedicated heat exchanger for waste heat recoveryWaste heat recovery on the side of the electrolytic cellCell has been developed. The flow rate of the heat transferring medium in the heat exchanger has been optimized and controlled, and the heat extraction rate has been adjusted to ensure stable operationOperation of the electrolytic cellCell without affecting it. The radiant heat on the side of the electrolytic cellCell shell has been efficiently recovered. The technology was tested in an industrial scale on a 200 kA test cellCell. The results showed that the overall operationOperation of the aluminum electrolysisAluminum electrolysis cellCell waste heat recoveryWaste heat recovery system was stable and efficient, with an average heat recoveryRecovery of 77 734 kJ/h, equivalent to 21.59 kWh, 317 kWh per ton of aluminumAluminum, and a heat recovery efficiencyHeat recovery efficiency of 99.71%. The system has achieved stable, efficient, and precise regulation of heat recoveryRecovery within the range of 18.44–21.59 kWh, and can optimize and regulate the furnaceFurnace, which is conducive to the long-term, efficient, and stable production operationOperation of aluminum electrolysisAluminum electrolysis cellsCell.

Commercial aluminum fluorideAluminum fluoride production is currently dependent on fluorspar, listed by the USGS and EU as a critical mineral, as a feedstock. Surplus pure bathPure bath, continuously generated during aluminum electrolysisAluminum electrolysis from a reaction between the sodium oxide present in aluminaAlumina and the molten cryolitic bath, presents an option as an alternative fluoride source for the production of aluminum fluorideAluminum fluoride. Solidified cryolitic bath is composed of numerous different fluoride phases including cryolite, chiolite, calcium cryolite, and neighborite. An elevated temperature, solid-state reaction between aluminumAluminum sulfate and solidified cryolitic bath is capable of converting the fluoride components of the bath to aluminum fluorideAluminum fluoride and sodium, calcium, and magnesiumMagnesium sulfates. The sulfates can then be separated from the aluminum fluorideAluminum fluoride fraction through a sequence of aqueous washes. Due to the low aqueous solubilitySolubility of aluminum fluorideAluminum fluoride, this results in a solid fraction with purity comparable to commercially available smelter grade aluminum fluorideAluminum fluoride.

After successful implementation of NCCT+ CellCell Technology, SAMI and China SPIC Inner Mongolia Branch cooperated to select 5 pots in 350 kA potline of Huomeihongjun Aluminum smelterAluminum smelter for low carbon emissionLow carbon emission experiment. Based on the evaluation of original performance, busbar configuration (Magnetic fieldMagnetic field upgrade & NSBT), CathodeCathode block group & lining (NCCT+), superstructure and pot shell of the test pots are upgraded. After upgrade, the stability of MHDMHD including magnetic fieldMagnetic field distribution and uniformity have been significantly improved by more than 50%, and ultimate ACD, metal horizontal current, CVD, and the busbar voltage drop are also reduced obviously. Accompanied by the application of 15cm low metal height management technologyLow metal height management technology, the half year excellent performance at 366 up to 377 kA with 94.6% current efficiencyCurrent efficiency and net specific energy consumptionSpecific energy consumption of <12 180 kWh/t–Al has confirmed that the technology upgrading has achieved prominent carbon reduction and economic benefits.

An estimate of MHD stabilityMHD stability is an important criterion when attempting to increase the aluminium reduction cellAluminium reduction cell efficiency. The MHD stabilityMHD stability is achieved by optimizing the magnetic fieldMagnetic field and the electric current distributionCurrent distribution in the liquid metal. The magnetic fieldMagnetic field distribution is mostly determined by the external busbar network and the magnetized steel parts, while the electric current in the liquid metal is affected by the design elements of anodeAnode and cathodeCathode block collector bar construction details. Theoretical studies of MHD stabilityMHD stability often rely on a simplified uniform current distributionCurrent distribution over the cathodeCathode bottom. ModellingModelling of commercial cellsCell requires a detailed 3D representation of the cellCell cathodeCathode, coupled to the liquid metal. The software MHD-VALDIS permits to account for current distributionCurrent distribution in the liquid metal and the cathodeCathode including variable material properties, contact resistancesContact resistance, temperature dependent collector conductivity, carbon block length and ledgeLedge profile along cellCell perimeter. The software permits to compute full electric current and magnetic fieldMagnetic field 3D distribution change in time associated with the velocities and metal/electrolyte interface wave development leading to damping or growth in an unstable cellCell. To quantify the instability the damping rate is determined using a new technique based on the consecutive wave peak heights comparisonComparison. Examples of application to a commercial Trimet cellCell are presented.

In the push to improve key performance indicators (KPIs) of existing smelters, Hall-Héroult cellCell retrofits projects are getting very popular especially in China. The cathode assemblyCathode assembly is a prime candidate for redesign as it is possible to reduce the cathode voltage dropCathode voltage drop (CVD) and the metal pad horizontal current at the same time leading to a reduction of the cellCell energyEnergy consumption. A new cathode assemblyCathode assembly design concept developed by Elkem is being investigated in the current work using three types of complimentary models. The results are presented and compared in this paper.

In February 2022, a power outagePower outage in Potline 2 in ALBRASALBRAS shut down 223 cellsCell. As part of the restarting process, a methodology for the evaluation and classification of cathodesCathode was developed to support the decision on which ones to restartRestart or not. As inspections proceeded, some cellsCell presented damage to the rammed slope that required repairs. A methodology for patching was standardized, aiming to avoid potential future ironIron contamination. 211 cellsCell were inspected, 186 were restarted, and 108 were repaired according to the new methodology. This group performed better in the subsequent year: only 10% had to be relined, against 32% in the not-repaired group; 9% of the cellsCell were restarted due to failure, against 14% in the other group. The same group also performs better in terms of ironIron contamination of operating cellsCell. ALBRASALBRAS extended the new methodMethod to all four potlines after the end of the restartRestart.

The pot relining methodMethod at INALUM is divided into two methodsMethod, namely, a full repair and a partial repair. The partial repair methodMethod has a weakness; when a cracked cathodeCathode block is found, this methodMethod cannot be implemented and has to continue with the full repair methodMethod. Improvements were made in 2021 to replace several damaged cathodeCathode blocks with new ones, combine the new cathodeCathode blocks with the old ones, and continue the partial repair work instead of having to switch to full repair work. The application test of the new partial repair methodMethod was carried out on pot R-117. The average operational parameters from the test pot show similar performance to a reference pot. The partially repaired pot managed to get an additional 2 years of age and a cost savingsCost Saving of 109,725 USD. Moreover, the application of a new partial repair reduces the potential generation of spent pot lining (SPL) by approximately 50 tons per pot.

Aluminium smeltingAluminium smelting is a very energyEnergy-intensive process; therefore, reducing power consumption has been a continuous focus of the aluminium smeltingAluminium smelting industry for many decades. A unique concept of electrical collector plate (ECP) has been developed and tested in industrial reduction cellsCell to validate the thermal electrical performances and financial benefits of the ECPECP design. The development process including thermo-electrical and thermo- mechanicalMechanical modellingModelling of various ECP designs will be discussed. The ECPECP cathode assembliesCathode assembly were installed and tested in industrial reduction cellsCell. Significant energyEnergy savings were realised and validated through stable operationOperation of trial cellsCell. It is also found that ECP cathode assembliesCathode assembly can provide versatile applications such as leveling out the cathodeCathode surfaceSurface current density and reducing horizontal current flow in the metal pad.

The electrical resistance of the cathode assemblyCathode assembly contributes to 8% of the 4.2 V operating voltage of a 400 kA reduction cellCell, and electrical contact resistanceContact resistance (ECR) at the cast ironIron-carbon cathodeCathode interface causes most of this resistance. Since ECR depends on temperature and contact pressure at the interface, it indirectly depends on initial air-gap distribution and its evolution during the operationOperation. Accurate determination of this important parameter remains a challenge even today. In this paper, a 3D scanning3D Scanning approach is proposed to measure the initial air-gap distribution at the cast ironIron-carbon cathodeCathode interface of an industrial cathode assemblyCathode assembly. Coupled with advanced software for accurate geometrical data processingProcessing, this well-established approach offers promise for interface analysis in various applications. The results obtained reveal a highly asymmetric air-gap distribution on both the top and side contact surfacesSurface of the cast ironIron-carbon cathodeCathode interface.

Coal tar pitchCoal tar pitch (CTP) is traditionally used as binder material for the manufacturing of carbon anodeCarbon anode. Worldwide, researchers are exploring alternate materials of CTP due to its limited availability as well as high polycyclic aromatic hydrocarbons (PAHs) content. Key requirements from a binder material for making a good quality anodeAnode are coking value (CV), quinoline insoluble (QI) content, viscosity, and wettabilityWettability. In this study, petroleum pitchPetroleum pitch (PP) is blended with CTP in different proportions for making lab-scaleLab scale anodesAnode. Results showed adequate anodeAnode properties till 20% blending of petroleum pitchPetroleum pitch. Further increase in blending ratio deteriorates the anodeAnode properties such as baked anodeAnode density and compressive strength due to low CV and QI content of petroleum pitchPetroleum pitch. To improve the QI content in samples with higher proportions of petroleum pitchPetroleum pitch, appropriate additives were added. The result of this analysis is also discussed in this paper.

BiopitchBiopitch (BP) is being developed as a potential replacement for coal-tar pitch (CTP) in carbon anodesCarbon anode for primary aluminiumPrimary aluminium production. Since the softening point (SP) of BP is lower than that of CTP, the mixing temperature can possibly be lowered, not only to save thermal energyEnergy but also to optimize the mixing parameters. The goal of the current study was to investigate the effect of mixing and pressing variables on BP-based carbon anodeCarbon anode properties. AnodeAnode pastes were made while varying four different production parameters according to a two-level full factorial design of experiment: BP/CokeCoke mass ratio 16–20%, mixing temperature 160–180 °C, mixing time 8–12 min, and pressing temperature 130–150 °C. The green apparent density (GAD), the baked apparent density (BAD), and the specific electrical resistivity (SER) of the baked samples were measured using standard test methodsMethod. Improved production parameters are suggested to achieve high GAD, BAD, and low SER.

Rio Tinto operates three cokeCoke calcinationCalcination plants in Canada. The kilnsKiln differ not only in size and production capacity but also in the design of the nozzles for third air injection. At one site (calciner A) especially, carbonaceous depositsDeposits form on the surfaceSurface of kilnKiln refractoriesComputational fluid dynamics. Computational Fluid Dynamics (CFD)Computational Fluid Dynamics (CFD) was used to simulate the impact of different nozzle designs on depositDeposits formationFormation. It was shown for calciner A that the design of the nozzles contributes to higher gas velocities and strong vortex. These conditions favour the entrainment of fine cokeCoke particles, thought to be the origin of depositDeposits formationFormation. The simulationSimulation showed that entrainment could be reduced by a nozzle redesign similar to the other two sites. However, any redesign would be accompanied by a lower cokeCoke temperature in the calcinationCalcination zone and thus a poorer process performance. The simulationSimulation was used to identify the best compromise between depositDeposits formationFormation and kilnKiln performance.

At Rio Tinto operated calciners, the masses of the green petroleum cokePetroleum coke (GPC) feed and of the produced calcined petroleum cokePetroleum coke (CPC) are continuously measured by belt scales. In spite of frequent calibration, CPC yieldsYield based on the measured mass flows are not always accurate. Thus, CPC yieldsYield are calculated from GPC deliveries, CPC shipments, and inventory changes. This approach only allows calculating CPC yieldsYield over long periods. An alternative methodMethod was therefore developed. During calcinationCalcination, GPC loses humidity and volatiles. CokeCoke fines are entrained by the gas flow and swept out of the kilnKiln or oxidised. The quantity of lost fines can be determined by GPC and CPC granulometryGranulometry analysis. The CPC yieldYield is calculated from the combined mass losses. Calculated yieldsYield agree well with values determined by the long-term mass balances. Furthermore, short-term yieldYield changes can be detected.

The blending of shaft and rotary calcined cokesCoke has become relatively common in the aluminum smeltingAluminum smelting industry. One of the widespread concerns with shaft cokeShaft coke is the view it is more “dusty” than rotary cokesRotary coke. This can be an issue when handling shaft cokeShaft coke at storage facilities and when importing/exporting over dock facilities. To understand the relative risk of fugitive dustFugitive dust generation during handling shaft cokeShaft coke, a study was made comparing the degradationDegradation tendencies of shaft cokeShaft coke compared to rotary cokeRotary coke when tested under the same conditions. Tests simulating cokeCoke migration such as from a conveyor or being discharged from a silo (“cokeCoke on cokeCoke”) and cokeCoke dropping such as filling a silo (“cokeCoke impact”) were developed. The results of this study are presented.

The bulk densityBulk density of petroleum cokePetroleum coke used for anodeAnode manufacture is important to aluminum smeltersAluminum smelter as it generally relates to anodeAnode baked density, a key anodeAnode quality parameter. CokeCoke bulk densityBulk density has been extensively studied, including previous work by BP that showed how particle shapeParticle shape is modified by different crushers, and that changes in shape influenced cokeCoke bulk densityBulk density. These laboratory studies indicated that the influence of shape on the variation in Vibrated Bulk DensityBulk density (VBD) of a range of anodeAnode filler materials was of similar magnitude as porosity. Further work showed that the VBDVBD of blends of shaft and non-shaft (Rotary hearth) calcined cokesCoke could be improved by jaw crushing the shaft cokeShaft coke in the blend. This work has been continued in further laboratory studies. The impact on VBDVBD of separately crushing the shaft and non-shaft calcined blend components using different crusher types at several particle sizeParticle size ranges has been studied. The results of this work are presented and the ability to improve cokeCoke blend quality by modifying shape through selective crushing is discussed.

Petroleum cokePetroleum coke is one of the principal constituents of carbon anodeCarbon anode, used in the Hall–Héroult processHall-Héroult process which is overconsumed by air and CO2 reactions. The inhibition of the air reaction by adding boron on cokeCoke particles could be an effective technique to reduce carbon consumption. This work aims at revealing whether boron impregnationBoron impregnation affects the cokeCoke porosity and, in this eventuality, how it influences its air reactivity. The porosity of impregnated and unimpregnated samples was characterized in several pore size ranges, measured by mercury porosimetry. The pore volume variation of each pore size range as a function of carbon conversion was assessed and used to determine the range of the most active pores for air oxidation. It has been confirmed that boron blocks small pores, within the size range of 0.0004–0.025 µm. The active pores, being in the range of 0.1–10 µm, were however not affected by boron addition.

AnodeAnode baking furnacesFurnace can have significant emissions of sulphuric gases, SO3SO3 is of particular concern due to its acidity. It can condense to sulphuric acid and result in severe corrosionCorrosion, as well as giving the “blue plume” of sulphuric acid mist around the chimneys. In addition, SO3SO3 mist is a significant problem for many CO2 capture technologies. The NaCl trap methodology was used for sampling, selectively reacting SO3SO3 with NaCl at 200 °C to form Na2SO4. SO2 and other sulphuric compounds will not react under these conditions. All samples were collected with two traps in series. It was found that sulphur was only present in the first salt trap, and no breakthrough was observed. Analytical sensitivity for the samples was estimated, the main factors determining the level of detection (LOD) are background sulphur from the salt and analytical accuracy in the ICP-MS methodology.

In the face of the need for process optimization to achieve efficient resource consumption and quality gains, the present study addresses practices that have led to performance improvement in the anodeAnode baking process in horizontal furnacesFurnace. Key actions included optimizing the logic of heavy fuel injection, developing process controls, equipment parameterization, and developing new routines. These actions contributed to the following gains when comparing the years 2020 and 2022: a 5.7% reduction in the standard deviation of equivalent temperature, an increase of 41 °E in the equivalent temperature, an 8.7% increase in adherence to the baking temperature, and decreased 75% in underbaked occurrences. These increments also contributed to the reduction of dust generation in the electrolytic cellsCell.

In order to improve the protective performance of the surfaceSurface of anode stubAnode stub for aluminum electrolysisAluminum electrolysis, an Fe-Al alloyAl alloys layer was prepared on the surfaceSurface of Q235BQ235B by pack aluminizingAluminizing. The microstructureMicrostructure, high-temperatureHigh-temperature oxidation resistance, microhardnessMicrohardness, wear resistance, and mechanical propertiesMechanical properties of aluminized layer were analyzed by scanning electron microscope, oxidation test, and abrasive wear test. The results showed that when Q235BQ235B was aluminized at 850 ℃ × 4 h, the maximum depth of aluminized layer reached 500 μm, the maximum hardnessHardness of aluminized layer reached 750 HV, and the wear resistance was 17 times than that of Q235BQ235B material. Under high temperatureHigh-temperature, a dense and uniform aluminaAlumina film layer on the surfaceSurface was generated in-situIn-Situ, which improved the oxidation resistance of Q235BQ235B material by more than 95 times, while the tensile strength and yieldYield strength remained unchanged after aluminizingAluminizing.

Gas-fired furnacesFurnace are the primary source of scope 1 carbon emissions in secondary aluminumAluminum production. Possible retrofitting solutions include oxyfuel burners, air-hydrogenHydrogen combustionCombustion, and electric plasma torchesPlasma torch. In this context, many questions remain regarding the performance of these technologies and their impact on emissions and metal quality. This paper presents the results of an experimental campaign on a furnaceFurnace equipped with a 47 kW oxyfuel burner operated with natural gas, hydrogenHydrogen, and mixtures of both. The objectives of this study are to validate previous simulationSimulation models for melt rate and energyEnergy consumption, that indicate oxy-hydrogenHydrogen as a viable retrofit solution, to investigate the impact on drossDross rate and magnesiumMagnesium loss for a 5000 series alloyAlloys, and to demonstrate the feasibility of the oxy-hydrogenHydrogen concept.

For decarbonizationDecarbonization of aluminumAluminum cast houses, measures for fuel switching and to reduce energyEnergy consumption for heating, with its associated emissions, are being evaluated. In that context, the case of electric plasma torchesPlasma torch is experimentally investigated as a solution to retrofit fossil fuel fired furnacesFurnace. This paper presents results of a test campaign on a furnaceFurnace equipped with a direct-current plasma torchPlasma torch able to operate with nitrogen, air, or argon as plasma working gases. The performance of the furnaceFurnace under varying plasma torchPlasma torch operating conditions (working gas, gas flow rate, power) is investigated and compared with the reference case of a 47 kW oxy-fuel burner running with natural gas. The results show that when operating with a plasma torchPlasma torch system the thermal profile and energyEnergy efficiency of the furnaceFurnace are equivalent or better than those obtained with an oxy-fuel system without significant differences in drossDross formationFormation and metal quality, hence proving the feasibility of the concept for both retrofit of existing furnacesFurnace and for new designs.

To achieve the goal of climateClimate neutrality in aluminumAluminum casthouses, all furnacesFurnace currently heated with fossil fuels should be able to be switched to hydrogenHydrogen burner technologies in the future. This primarily entails a change in the furnaceFurnace atmosphereAtmosphere. In addition to the elimination of CO2 emissions, increased water vaporWater vapor contents must inevitably be expected when combusting H2. While the oxidation-inhibiting effect of carbon dioxideCarbon dioxide on aluminum-magnesiumMagnesium melts is well known and extensively studied, the effects of water vaporWater vapor on oxidation behavior are still largely unexplored. Depending on the burner setup, H2O contents can range from 17 vol.% (CH4 + Air) to theoretically over 95 vol.% (H2 + O2). In this work, an isolated examination of the influence of H2O on the oxidation behavior of molten AlMg alloysAlloys takes place. In addition to gravimetric analyses, an optical investigation of the resulting oxide layers is also carried out. It can be shown that high H2O contents in the furnaceFurnace atmosphereAtmosphere have a similar oxidation-inhibiting effect compared to CO2.

Alloying is usually a necessary operationOperation before castingCasting, and alloying elements with higher meltingMelting point than the melt temperature that typically gives slow dissolutionDissolution rates. Higher aluminiumAluminium content in Al-Mn master alloysMaster alloy corresponds to higher dissolutionDissolution rates. Oxide layers towards the Mn alloyAlloys reduce the dissolutionDissolution rate. Penetration of liquid Al into the Mn alloyAlloys structure increases the dissolutionDissolution rate unless a solid alloyAlloys is formed. In this study, approximately 0.5 kg pure aluminiumAluminium was melted in a 16 kW induction ladle. Laser-Induced Breakdown SpectroscopyLaser-induced breakdown spectroscopy (LIBSLIBS) was used to determine the chemistry continuously in the melt as various alloying compositions from 20 to 100% Mn were introduced. The melt temperature was maintained isothermal at temperatures 720, 770, and 800 °C. From the results the dissolutionDissolution rate for the various Mn alloyingMn alloying elements, in this set-up, is calculated. The results are useful for upscaling precise alloying practises in cast houses.

Henan Zhongfu Industrial Co Ltd is a major aluminium producer making more than 600,000 tonnes of canbody and foil stock annually. After conducting successful trials in 2021 Optifine 3:1 high efficiency grain refiner was fully adopted in production usage which has resulted in reduced grain refiner consumption and improvements in finished product quality. Details of the trials conducted on 5182 can lid stock leading up to the changeover and the results achieved in production with Optifine are presented.

Efficient thermal management requires a combination of effective insulation and low-cost solution that yieldYield straightforward and predictable outcomes. Pourable backup insulations are one of many products used to reduce thermal loss, particularly during metal transfer in the cast house. They are typically two-part product and prepared by on-site mixing of a mineral binder suspension and a liquid acid activator. However, their usage presents several challenges for customers including unstable thermal insulationThermal insulation, handling hazardous substances, difficulties associated with the mixing preparation and pouring process, lengthy drying process, controlling the volume expansion, and high shipping costs of two-part products. To overcome these challenges, a new one-part solid powder mixture product is proposed. This non-expanding pourable product only requires in-place mixing with plant water. The efficiency of this product is already proven in operationOperation. An example showcasing its application in transfer launder, holding furnaceFurnace, crucible, and ladle will be presented.

Chvorinov’s rule is a well-known relationship which relates the solidificationSolidification time of a simple shape to the ratio of the volume to surfaceSurface area. In this study, we propose a similar relationship for the meltingMelting rate of scrap charged into a molten pool (as in a sidewell furnaceFurnace). Experimental meltingMelting trials are used to establish heat transferHeat transfer conditions at the scrap surfaceSurface. These parameters are then used to build a numerical model of the meltingMelting process and analyze the impact of size and shape on meltingMelting times. From the combined experimental and numerical results, an expression is proposed which relates the shape of input material to its meltingMelting time. The new melt rate expression is used to predict the furnaceFurnace performance of different scrap form factors.

In a world striving for the conservation of natural resources, metal recyclingRecycling is an essential component of sustainable resource management. Continuous scientific research into the parameters controlling the recoveryRecovery rates of the applied metallurgical treatments both promotes technological advancements in the design of high-efficiency resilient processes and enables their optimization at the implementation phase. In this work, a series of lab-scale testing data was generated to study the relationship between the delacquering degree and recoveryRecovery rate in the pyrometallurgical recyclingRecycling of Used Beverage CansUsed Beverage Cans (UBCs). The effect of the atmosphereAtmosphere on thermal delacquering kinetics was studied. The obtained Temperature-Delacquering Degree correlation was utilized to prepare UBC samples of varying delacquering degrees, which were subsequently melted by two procedures: direct meltingMelting and addition into AA3104 hot heel. AssessmentAssessment of metal recoveryRecovery employing different methodologies, including cast metal weight and separation of entrapped aluminiumAluminium in the drossDross, both mechanically and after re-meltingMelting, demonstrated key affecting parameters.

Removing transition metal impuritiesTransition Metal Impurities is vital in producing high-conductivity aluminumAluminum for wire and cable applications. These impurities, primarily titaniumTitanium (Ti) and vanadium (V), can significantly reduce electrical conductivity. To address this challenge, laboratory-scale experiments were performed, focusing on the performance of aluminumAluminum-boron master alloysMaster alloy, specifically Al-3% B (AlB2 phase) and Al-8% B (AlB12 phase), in eliminating Ti and V from electrolysisElectrolysis metal ingots. In the present study, three critical parameters were addressed, i.e., holding time, stirring, and fluxing. All three parameters yielded positive outcomes, enhancing the electrical conductivity of the cast material. Cast house trials were conducted using Al-5% B (AlB2 phase) and Al-8% B (AlB12 phase). Furthermore, the melt qualityMelt quality was assessed through the Porous Disc Filtration Apparatus (PoDFAPoDFA) methodMethod. These trials were conducted in the aluminumAluminum wire rod cast house, where the 1370 alloyAlloys wire rod production occurs. The results obtained from the cast house trials provided valuable insights. Specifically, using the Al-5% boron master alloyMaster alloy with the AlB2 phase demonstrated its capability to yieldYield a cleaner melt, as evidenced by a reduced total inclusionInclusions count.

This article aims to present the importance of standardizing the profile and sizes of launder systemsLaunder system used in non-ferrous metal foundriesFoundry. A global standardization of these aspects would bring significant benefits, such as reducing the lead time for replacement of refractory materials by suppliers and substantial financial gains by minimizing the need for manufacturing custom molds for each project or client. Moreover, standardization would enable foundriesFoundry to conduct comparative studies among the different materials available in the market since the shape of the launder systemsLaunder system would no longer be an influential factor, focusing instead on the compositions of the refractories used in their construction. Another crucial point is that by standardizing the profile of refractory launder systemsLaunder system, this standardization would extend to the entire channel system, including space for thermal insulationThermal insulation, the profile of metal plates, and lid systems.

Filtration is a widely used methodMethod for removing non-metallic inclusionsInclusions/bifilms from molten aluminiumAluminium, where Ceramic Foam Filters (CFFs)Ceramic Foam Filters (CFFs) dominate due to their cost-effectiveness and easy use. While many CFFs are phosphate-bonded and have been considered inert when in contact with molten aluminiumAluminium, recent studies have shown that this is not the case, making it necessary to study even non-phosphate-bonded CFFs. Through aluminiumAluminium melt pilot-scale filtration trials using a 60826082 alloyAlloys and commercial CFFs based on sintered aluminaAlumina (Al2O3) and silica (SiO2), the present study reveals that even these filters can react with the molten aluminiumAluminium. Microscopic characterizationCharacterization of unused/used CFFs confirmed two notable observations: (i) indications of silicon depletion in the used filters and (ii) minimal reactivity. Based on the microscopic evaluation and LiMCALiMCA data, the silicon depletion and the conditions leading to silicon depletion are discussed in view of its effect on filtration efficiencyFiltration efficiency.

The PoDFAPoDFA inclusionInclusions measurement is achieved by identifying the inclusionsInclusions and their concentration in the melt for each type with a trained operator. The standard technique is realized by using a square grid with an optical microscope to count the total area with each detected square. This manual and non-efficient methodMethod requires a lot of time and effort and can generate important variations in PoDFAPoDFA results for reproducibility and repeatability. In the past, there were many unsuccessful attempts to automatically detect, count, and classify all inclusionInclusions types due to the complexity of the application. Disc sampling, image artifacts, polishing defectsDefects, and metallurgical constituents are some examples that can interfere with the inclusionInclusions detection and the measurement methodology. Commercial image analysis systems with threshold options and Boolean logical operationsOperation are not sufficient to automate the solution. The implementation of artificial intelligenceArtificial intelligence technologies such as supervised machine learningMachine Learning (ML) algorithms are necessary to automate this complex methodMethod. The benchmarking study was achieved between the standard PoDFAPoDFA methodology compared to the artificial intelligent way. Results show that the new technique exhibits a good correlation and a high potential for industrial use.

Quality controlQuality control of aluminumAluminum is critical for a wide range of applications across different industries. The main methodMethod for assessing aluminumAluminum cleanlinessCleanliness is PoDFAPoDFA. The manual nature of the methodMethod imposes limitations in speedSpeed and statistical robustness that made aluminumAluminum producers and suppliers call for alternative methodsMethod with higher degrees of standardization and automation in recent years. We previously demonstrated the AutomatedAutomated Metal CleanlinessMetal cleanliness Analyzer (AMCA) methodMethod as a feasible way of assessing metal cleanlinessMetal cleanliness from PoDFAPoDFA micrographs using digital deterministic image segmentationImage segmentation techniques. Here, we continue this work by combining the deterministic approach with unsupervised machine learningMachine Learning (ML) for decreasing false-positive detections and achieving a higher degree of automation. Our results show that this approach generates metal cleanlinessMetal cleanliness data closer to PoDFAPoDFA reference data than previous implementations on the one hand and decreases algorithm setup time for new types of micrographs (e.g., alloysAlloys) by automating parts of the algorithm.

The rapid, online, real-time analysis ofMolten aluminum molten aluminum alloysAluminum alloys without sample preparation is required for saving time and energyEnergy in alloyAlloys production. LIBSLIBS is a fast, easy to use, and sensitive analysis technique compared to other spectroscopic techniques. In this study, Al 6028 and Al7075 series alloysAlloys were analyzed with LIBSLIBS system developed at ST Advanced Research Center. For measurements, a diode pumped Nd:YAG with 100 mJ energyEnergy, 4.4 ns pulse length, 10 Hz repetition frequency, and a Czerny Turner type spectrometer with a 0.1 nm resolution were integrated into the ST LIBSLIBS system. A customized tube was utilized to focus the laser pulses into 700 °C molten aluminumMolten aluminum using a 50 cm focal length lens. Under argon gas pressure, spectral measurements were made through the molten aluminumMolten aluminum in the furnaceFurnace. Principle Component Analysis (PCA) technique was used for the classification of aluminum alloyAluminum alloys types. The different alloyAlloys series are clustered in different regions via PCA technique. This marks STLIBS’s first productive outcome from a high-temperatureHigh-temperature analysis.

The assessmentAssessment of aluminumAluminum melt cleanlinessCleanliness has traditionally relied on labor-intensive and subjective manual processes. The present study builds upon prior digital image analysis to quantify inclusionsInclusions in micrographs of PoDFAPoDFA samples. Through the integration of deterministic methodsMethod, unsupervised Machine LearningMachine Learning (ML) (ML), and neural networksNeural networks, cleanlinessCleanliness data comparable to PoDFAPoDFA grid assessmentsAssessment has been achieved. Overcoming the challenge of generating sufficient and accurate training data for neural networksNeural networks, the suggested approach has been refined. Enhanced isolation strategies for target classes have resulted in higher-quality training data, elevating the prediction accuracy of the neural networkNeural networks. Post-processingProcessing of neural networkNeural networks predictions has also been improved. The integrated approach presented here demonstrates more reliable cleanlinessCleanliness data than previous implementations. Offering a promising alternative to manual PoDFAPoDFA assessmentsAssessment, this integrated approach improves efficiency and reduces human biases.

We report Ti concentration measurements in dilute Al-Ti-B alloysAlloys, acquired from direct chemical analysis of the molten metal by laser-induced breakdown spectroscopy (LIBS)Laser-Induced Breakdown Spectroscopy (LIBS). By LIBSLaser-Induced Breakdown Spectroscopy (LIBS) it is possible to analyze the influence of B addition on the concentration of dissolved Ti in the melt. After the addition of B, the dissolved Ti concentration is slowly reduced, with the kinetics strongly influenced by the Ti/B ratio and the melt temperature. The experimental observations are consistent with the formationFormation of TiB $$_{2}$$ 2 around Al-borides. The experiments confirm that LIBSLaser-Induced Breakdown Spectroscopy (LIBS) measurements of the liquid metal enable the real-time study of the kinetics of boron treatment.

In the aluminumAluminum industry, the testing of semi-finished and finished products is the basis for consistent process management, quality controlQuality control, and certification. The uncertainty of these measurements, in combination with the uncertainty of the production processes, can increase the risk of wrong decisions in closing the quality-assurance loop. This paper describes our experience of using tools such as guard bandsGuard bands and quality decision-support analyzers based on measurement uncertaintyMeasurement uncertainty as well as the uncertainty of some of the most frequently used processingProcessing paths. The tools were applied to improve different stages in the production and quality certification of wroughtWrought aluminumAluminum-alloyAlloys products. Examples of the practical use of these tools when evaluating the results of chemical, mechanicalMechanical, and metallographic testing and the conformity assessmentAssessment of various extruded, rolled, and forged products are described. With the use of these tools, we ensure the compliance of comparative measurements and the effective reduction of costs related to quality.

AluminumAluminum drossDross is a by-product generated during molten aluminumMolten aluminum treatment and castingCasting process. Knowing the composition of the drossDross will provide better environmental solutions through recyclingRecycling and reusing. In this research, Rietveld XRDXRD methodMethod is used to identify the crystalline phases present in drossDross. The XRDXRD analyses were used to develop template files to ease the phase identification process. The Alpha AluminaAlumina phase is carried out by Rietveld XRD and separate XRDXRD application since it is a crucial phase in aluminum smeltingAluminum smelting process. Omnian XRFXRF standardless application was able to obtain the trace elements available in drossDross. Unifying sample preparation for XRDXRD and XRF provided faster data reporting. In addition, Carbon content in drossDross is provided by a modified calibration of Leco Carbon analyzer. This methodology identified the crystalline phase of drossDross, the available trace elements, and the carbon content successfully with high accuracy and the fastest possible reporting time.

Iterations of thermomechanicalThermomechanical modelingModeling on DC castingDC Casting of high-strengthHigh strength crack-proneCrack-prone alloyAlloys billetsBillet have been conducted to understand billetBillet start-upStart-up phase thermal stressThermal stress development and to optimize tooling design. Transient thermal stressThermal stress development during cast start at the billetBillet butt, billetBillet surfaceSurface, and inside the billetBillet are investigated; Connection of cracking with stress development at billetBillet butt is presented; Effects of starting head, wiper placement, and wiper placement location on the thermal stressThermal stress development are also examined. The billetBillet surfaceSurface rebound temperatures and cast-in TC temperatures from the modelingModeling agree well with those measured in the laboratory and in the field; the castingCasting campaigns on the AirSlip®AirSlip® mold package exhibit great billetBillet quality and high pit recoveryRecovery.

The thickening of the base of rolling slab ingots is colloquially known as butt swellButt Swell. Because traditional DC castingDC Casting systems are vertical and not truly continuous, this remains one of the remaining sectors of recoveryRecovery loss in the casthouse and at the scalper. Butt swellButt Swell is currently managed by using dynamic molds which adjust the mold bore as a function of castingCasting recipe to deliver flat ingot profiles. In this paper, we analyze the metallurgical origin of butt swellButt Swell in the DC castingDC Casting process. Based on this analysis, a novel bottom blockBottom Block design is proposed which reduces the extent of the butt swellButt Swell in the start-upStart-Up regime of castingCasting. Experimental results are reported in comparisonComparison to a standard reference case demonstrating a reduction in butt swellButt Swell. Subsequent rolling trials also indicate additional scrap reduction in the flat rolling process.

80798079 alloyAlloys, produced by the twin roll castingTwin-roll casting methodMethod, is widely used in the production of thin foils due to its hardnessHardness and elongation properties. However, some quality problems must be overcome in cold rolled foils that are thinned to a thickness of around 7 microns. At the beginning of the problems that need to be solved, pinholePinhole formationsFormation whose number is above the acceptance criteria come. In this study, pinholesPinhole caused by intermetallicIntermetallics or intermetallicIntermetallics-like structures containing Cr were investigated. However, in order to solve the problem, it should be known which metallurgical or mechanicalMechanical reasons cause pinholePinhole formationFormation. A number of characterizationCharacterization methodsMethod were applied to foil samples. It is aimed to make inferences about which production step or which operationOperation in the castingCasting system is the source of the problem.

Utilizing copper rollsCopper roll in twin-roll casting (TRC)Twin-roll casting due to high process productivitiesProductivity provided by high thermal conductivity of copperCopper when used as a shell material is a well-known application to fulfill the increasing material demand seasonally and EN-AW 3105 is one of those aluminum alloysAluminum alloys, which is produced by using a steel/copper rollCopper roll pair. However, as-cast material microstructureMicrostructure after solidificationSolidification is distinctive on the material surfaceSurface which is in contact with the copper rollCopper roll when compared to the other surfaceSurface in contact with the steel roll. These microstructural discrepancies observed at as-cast thickness are inherited in the final product after rolling and annealing processes to a certain extent. In this study, corrosionCorrosion properties of an EN-AW 3105 aluminumAluminum strip produced via TRC were scrutinized and it was concluded that the material surfaceSurface, which solidified in contact with the copper rollCopper roll performed better corrosionCorrosion properties with respect to other surfaceSurface.

Today’s focus in the aluminiumAluminium industry is promoting a circular economyCircular economy, thus meeting the US and the EU's ambition of reducing greenhouse gasGreenhouse gases emissions. This means replacing primary aluminiumPrimary aluminium with post-consumer scrap, which contains larger quantities of intermetallicIntermetallics forming impurities, particularly Fe and Si, which are detrimental to mechanical propertiesMechanical properties. We need to develop new generations of impurity-tolerant aluminium alloysAluminium alloys enabling reduced carbon footprintCarbon footprint through increased recycled content. To meet this objective, it is necessary to deepen our understanding of AlFeSi secondary phase nucleation and growth during aluminium alloyAluminium alloys solidificationSolidification. In this work, model 6xxx6xxx recyclingRecycling-friendly alloysAlloys were manufactured and unique in situ directional solidificationDirectional solidification experiments were performed. For the first time, nucleation and growth of α-AlFeSi and β-AlFeSi intermetallicsIntermetallics were observed in real time in thin samples of model 6xxx6xxx alloysAlloys. We discuss the effect of chemistry modificationModification and solidificationSolidification parameters on the AlFeSi phase nucleation and growth.

The thermal transfer performance in the primary cooling area during direct chill castingDirect chill casting plays a crucial role in the microstructureMicrostructure formationFormation process and thus exerts a major impact on the mechanical propertiesMechanical properties of cast aluminium alloysAluminium alloys. Understanding the influence of cooling rateCooling rate on phase formationPhase formation is essential for optimizing alloy designAlloy design. This study presents a comprehensive analysis of heat transferHeat transfer based on experimental results and its impact on phase formationPhase formation during the solidificationSolidification process of aluminium alloysAluminium alloys. Measurements were conducted on a laboratory-scale direct chill castingDirect chill casting plant (Indutherm VCC3000), with a focus on the primary cooling area. Therein, cooling gradients were determined using fiveFives thermocouplesThermocouples placed inside the graphite-mould walls and three implemented in the starter block. Tests were conducted as block castingCasting and no evaluation of the castingCasting speedSpeed was possible. Based on the obtained results, the influence of heat transferHeat transfer on the cooling gradient of the investigated system is discussed. In this regard, the research provides valuable insights for future studies into the correlation between heat transferHeat transfer, cooling rateCooling rate, and phase formationFormation during the solidificationSolidification of aluminium alloysAluminium alloys in a laboratory direct chill castingDirect chill casting plant. The findings contribute to the optimization of alloy designAlloy design, facilitating the production of aluminium alloysAluminium alloys with tailored microstructuresMicrostructure and improved mechanical propertiesMechanical properties.

Anodization of 1xxx and 5xxx aluminium alloyAluminium alloys sheets improves the corrosionCorrosion resistance, in addition to providing a bright and shiny appearance. These properties find application in a variety of building exterior and decorative purposes. However, Altenpohl zonesAltenpohl Zone are a typical defectDefects observed in some of the 1xxx and 5xxx series aluminium alloysAluminium alloys depending on their Fe-to-Si ratio. This defectDefects is a consequence of different ironIron bearing particles responding differently to etching during the anodizing process. Considerable research has been conducted to study Altenpohl zoneAltenpohl Zone formationFormation in 1xxx and 5xxx alloysAlloys. This paper aims to improve and extend the knowledge base where the influence of alloyAlloys chemistry, castingCasting speedSpeed, and castingCasting temperature on the formationFormation and extent of Altenpohl zonesAltenpohl Zone in a commercially available 5005 alloyAlloys has been studied. Based on the results, recommendations on chemistry and process parameters are provided to control Altenpohl zoneAltenpohl Zone formationFormation during DC castingDC Casting of rolling slabs.

Blackening and degradationDegradation of twin roll caster (TRC) tipsTips can be observed at the leading edge closest to the caster roll shell and on the hot face of the tipTips in the regions in contact with aluminumAluminum after prolonged contact times. Although commonly observed, the exact mechanisms involved in the blackening reactions have never been researched and documented in depth. This paper details the analysis and investigations performed, provides insight into the reactions, and offers a comprehensive understanding of the mechanisms involved. It is shown that silica, from both the colloidal binder and aluminosilicateAluminosilicate fibers used in the tipTips manufacturing process, gets reduced by molten aluminumMolten aluminum via the formationFormation of corundum and spinel phases, while blackening at the leading edge, is the result of staining from the release agent applied on the roll shell burning in the vicinity of the tipTips.

In the aluminumAluminum industry, slab castingCasting is a critical step to ensure high-quality products. Despite this importance, the industry lacks a reliable and accurate system capable of tracking how the process is evolving. GAP Engineering SA has the ambition to give eyes to the operators, by using cameras and images to monitor the ingot during the castingCasting process and to give them insights about the process by using the power of Computer Vision (CV), Machine Learning (ML)Machine Learning (ML), and Artificial IntelligenceArtificial intelligence (AI). On the business side, this development intends to bring novelty to the industry, by proposing a new product to the customers. In the first stage, our solution tracks the dynamic evolution of the butt curl in real time, eliminating the need for costly and invasive sensors. By harnessing the potential of AI to standard cameras and taking advantage of production data, our innovation predicts the ingot's future development with precision. Process managers gain unparalleled control, foreseeing potential ingot failures and avoiding wasting time, resources, and energyEnergy. With the help of a Digital TwinDigital twins, the system can be used to finely tune the castingCasting parameters to achieve the desired product quality. The HAWKEYE project is currently being developed and tested in collaboration with AluminumAluminum Duffel BV (AD). Thanks to the innovative vision of the partners and the equipment already in place on the G6 castingCasting machine, we can use the data presented by the castingCasting pit to refine our models.

The appearance of vertical foldsVertical folds (VF) is a known surfaceSurface defectDefects in direct chill (DC) aluminum castingAluminum casting of Al–Mg alloysMg alloys, which affects both productivityProductivity and quality in the scalper and downstream rolling process, respectively. In this study, a series of industrial DC castingDC Casting trials have been performed in terms of grain refinerGrain refiner additions and oxidation inhibitors with the objective to study their effect on VF formationFormation. The number, length, and width of the VF on the surfaceSurface of the produced ingots have been macroscopically recorded. In addition, the microstructureMicrostructure of corresponding as-cast samples has been examined by means of light optical microscopy (LOM) and scanning electron microscopy (SEM). Based on the results, a mechanism describing the contribution of oxidation and segregation phenomena on the formationFormation of vertical foldsVertical folds is presented. Finally, the efficiency of employed measures to constrain vertical foldsVertical folds generation has been evaluated.

There are two main present drivers for Al alloyAl alloys designAlloy design from a castingCasting point of view: alloysAlloys for additive manufacturingAdditive manufacturing for which the objective is to maximise solute supersaturation and conventionally cast alloysAlloys in which the recycled content must be increased. For the former, the idea is to promote solute trapping. For the latter, a possibility is to distribute constituent particles as finely and uniformly as possible in the solidificationSolidification microstructureMicrostructure by promoting dendritic grain growth morphology. In both cases, minimising solute diffusivity in the liquid phase is desirable. Now this property is governed by atomic arrangement, that is, short- and medium-range order in the liquid, in contrast with the crystalline order of fcc-Al. The present paper aims at giving an overview of this scientific issue, with a focus on the results obtained by Ab Initio Molecular Dynamics modellingModelling of liquid Al–Mg, Al–Si and Al–Mg-Si alloysAlloys.

The rapid growth of industrialization and transportation has led to increasing concerns over greenhouse gasGreenhouse gases emissions and their impact on climateClimate change. As a result, industries are constantly seeking innovative solutions to reduce their carbon footprintCarbon footprint. One promising avenue is the integration of new aluminiumAluminium-scandiumScandium (Al-Sc) alloysAl-Sc alloys, which offer unique properties and capabilities to address emissions reduction in various sectors. This paper delves into the role of Al-Sc alloysAl-Sc alloys in fiveFives key areas: aerospace, automotiveAutomotive, shipbuilding, additive manufacturingAdditive manufacturing, and high-voltage (HV) conductors. In the automotiveAutomotive sector, Al-Sc alloysAl-Sc alloys present an opportunity to streamline production and minimize emissions by consolidating the number of alloysAlloys used in vehicle construction. For instance, by replacing conventional 6xxx6xxx-series alloysAlloys with 5xxx-series+Sc for both inner and outer panels, the need for agingAging processes is eliminated, further reducing CO2 emissions. In airplane manufacturing, the traditional 2024 sheet alloyAlloys, which requires an additional Al cladding, can be replaced by the 5028 Al-Mg-Zr-Sc alloyAlloys resulting in a 4–5% weight saving. In shipbuilding, the adoption of 5xxx-series +Sc alloysAlloys proves advantageous as it can enhance weld strength and mitigate sensitization issues. Consequently, vessels’ service life could be extended while reducing overall weight, leading to notable emissions reductions. Furthermore, the potential of Al-Sc alloysAl-Sc alloys in additive manufacturingAdditive manufacturing (AM) is explored. Tailored alloyAlloys compositions developed for AM applications, with strategic scandiumScandium and zirconium content, enable in-situIn-Situ precipitation during the AM process. This can eliminate the need for post-agingAging, making large-scale AM more feasible and cost-effective while promoting emission reductionsEmission reduction. Lastly, we discuss the application of Al-Sc alloysAl-Sc alloys in HV conductors. By incorporating scandiumScandium, these conductors can achieve increased strength without significant compromise to electrical conductivity, fostering a greener power transmission infrastructure. In conclusion, the utilization of new aluminiumAluminium-scandiumScandium alloysAlloys presents a promising pathway to curbing emissions in multiple industries, signalling a transformative shift towards more sustainable practices and environmental stewardship.

Our work focuses on improving the manufacturability and performance of Al–Si–MgAl-Si-Mg 6xxx6xxx series alloysAlloys for structural automotiveAutomotive components. ScandiumScandium is the most potent strengthening element in aluminum alloysAluminum alloys but interactions between Sc and Si have limited the use of Sc in high Si-containing alloysAlloys (6xxx6xxx). We demonstrate modified heat treatmentHeat treatment schedules for precipitation of potent Sc-containing dispersoids, which are stable during extrusionExtrusion and processingProcessing. Trace scandiumScandium additions increase strength and tear resistance in lightly alloyed 6xxx6xxx alloysAlloys and reduce extrusionExtrusion and heat-treating costs relative to alloysAlloys with comparable strength and tear resistance. In one example, an Al–0.5Si–0.5Mg alloyAlloys with an 0.09 wt% Sc addition increased T6 yieldYield strength from 276 to 372 MPa with ductility only decreasing from 21 to 18%. The role of castingCasting and homogenizationHomogenization on precipitation of these stable Sc-containing dispersoids will be discussed.

In this paper, the influence of various modes of deformation processingProcessing on the properties of flat rolled products made of 5081 and 5181 Al-Mg-Sc alloyAlloys system was studied. It is shown that the level of strength properties of annealed sheets depends on the degree of deformation during hot and cold rolling. A low sensitivity of the material containing 0.1 wt.% scandiumScandium to the degree of deformation during rolling, in relation to the material containing 0.03 wt.% scandiumScandium, has been found. The dependences of the influence of rolling temperature in the range of 410–500 °C on the mechanical propertiesMechanical properties of hot-rolled sheets of Al-Mg alloyMg alloys containing 0.1% Sc were obtained. The patterns of changes in the yieldYield strength of hot-rolled deformed semi-finished products depending on the rolling temperature and the degree of deformation have been revealed. It has been shown that the final level of strength properties depends primarily not on the amount of zirconium and scandiumScandium, but on the number and size of particles of the strengthening phase of the Al3(Zr, Sc) L12 type.

Al–Mn 3xxx alloysAl-Mn 3xxx alloys are widely used in the fabrication of multi-port extruded (MPE) tubes for aluminumAluminum heat exchangers. The industrial manufacture for those tubes consists of four steps: (1) homogenizationHomogenization, (2) extrusionExtrusion, (3) straightening/sizing, and (4) brazingBrazing. The combination of cold work and brazingBrazing could result in abnormally coarsened grains that have negative impacts on the in-service performance of MPE tubes. A 3xxx alloyAlloys microalloyed with 0.08 wt.% Sc and 0.09 wt.% Zr was assessed with respect to the grain structures after hot deformation and brazingBrazing, and a comparisonComparison was made with the base 3xxx alloyAlloys free of Sc and Zr. The flow stress of the base alloyAlloys during hot compression at 500 °C and 1 s−1 was 48 MPa, while the alloyAlloys with added Sc and Zr showed a higher flow stress of 61.5 MPa. EBSD maps after hot deformation showed that the alloyAlloys with added Sc and Zr exhibited more resistance to dynamic recoveryRecovery and dynamic recrystallizationRecrystallization. After the high-temperatureHigh-temperature simulated brazingSimulated brazing at 605 °C, the base alloyAlloys suffered from abnormal grain growthAbnormal grain growth, whereas the alloyAlloys with added Sc and Zr exhibited an elongated recrystallized microstructureMicrostructure with a finer grain size.

An abnormally coarsened grain structure after brazingBrazing can negatively affect the in-service performance of a brazed heat exchanger. One of the numerous beneficial effects from the Sc addition to aluminumAluminum is its retardation effect on recrystallizationRecrystallization and grain growth. In this work, dilute Al–0.07Sc and Al–0.07Sc–0.09Zr alloysAlloys were assessed with respect to the hot deformation and the post-brazingBrazing grain structure and compared with the base 1xxx alloyAlloys. The flow curves of the hot compression testsCompression tests showed that the Al–Sc–Zr alloysAlloys exhibited higher flow stresses compared to the base alloyAlloys. The microstructureMicrostructure of the deformed samples in all three investigated alloysAlloys exhibited a recovered microstructureMicrostructure, but both Sc-containing alloysAlloys showed an improvement in the resistance to dynamic recoveryRecovery. EBSD maps after a high temperature simulated brazingSimulated brazing showed that the microstructureMicrostructure of the base alloyAlloys suffered from abnormal grain growthAbnormal grain growth. Severe grain coarseningGrain coarsening was still observed in the recrystallized microstructureMicrostructure of Al–0.07Sc alloyAlloys after brazingBrazing. The combined addition of Sc and Zr in Al–0.07Sc–0.09Zr alloyAlloys suppressed the abnormal grain growthAbnormal grain growth, showing an improved control on the brazed microstructureMicrostructure. After post-braze agingAging at 350 °C for 4 h, the hardnessHardness of both Sc-containing alloysAlloys increased by 90–122% relative to the base alloyAlloys hardnessHardness.

Scalmalloy®, aScalmalloy 5xxx series aluminumAluminum alloyAlloys modifiedAluminum alloys with Sc and Zr to suit additive manufacturingAdditive manufacturing needs, displays significant potential for automotiveAutomotive and aerospace applications due to its exceptional strength, low density, and resistance to corrosionCorrosion. This study investigates the impact of ironIron, a prevalent impurity in secondary aluminumAluminum, on the microstructureMicrostructure and mechanicalMechanical propertiesMechanical properties ofScalmalloy Scalmalloy® produced via laser powder bed fusionLaser powder bed fusion (PBF-LB). ThreeScalmalloy Scalmalloy® variations were examined: the original composition and two modified versions with a total Fe content of 1.8 and 3.5 wt.%. Microstructural analysis through electron microscopy and X-ray diffraction unveiled the existence of metastable Fe-rich precipitatesPrecipitates at mid-low Fe concentrations, while stable Al–Fe intermetallicsIntermetallics were observed in the variant with high Fe content. The influence of these distinct microstructuresMicrostructure was assessed using hardnessHardness and compressive tests. These assessmentsAssessment demonstrated augmented material strength at room temperature when increasing the Fe content in the composition for both as-built and peak-aged conditions. However, this enhancement diminished when the alloyAlloys containing 3.5 wt% Fe was subjected to compression at 300 $$^{\circ }$$ ∘ C, resulting in outcomes comparable to the alloyAlloys with a Fe content of 1.8 wt.%. These findings contribute to an enhanced comprehension of the properties of commercial aluminumAluminum alloysAlloys containingAluminum alloys trapped impurities, which hold the potential to expand the utilization of secondary aluminumAluminum alloysAlloys withinAluminum alloys the additive manufacturingAdditive manufacturing industry.

Europe uses around 25% of the world metal production, including critical metals like Mg, Ti, Nb, REEs, and Sc. However, just around 2–3% of the world metal production is actually manufactured in Europe, resulting in a huge imbalance. Critical metals are indispensable in the green transition for producing renewable energyRenewable energy. Metals are not only needed in products like wind turbines, solar panels, electric cars or hydrogenHydrogen technology, they are needed too in the expansion of the electric grid. Basic metals like aluminiumAluminium and copperCopper are needed to double the grid in the next 10 years in order to coop with the enormous growth of renewable electric energyEnergy. The Green transition requires more critical metals like Li, Mo, Nb, V, Sr, Si, Ti, Mg, REE’s, and Sc. Most of these critical metals (Mg, Nb, Sc, Sr, and Ti) are not at all produced in Europe and have to be imported for 100%. The dependence on imports can lead to supply disruptions and lead to unacceptable high prices. New sustainable mines are needed for the long term to solve the metal supply imbalance. Another option for Europe is to focus more on Industrial Symbiosis (IS) projects. In an Industrial Symbiosis project, waste streams from one industry are used as a feedstock for other industries. EU MagnesiumMagnesium, ScaVanger, Scale-up, and Valore are examples of EU-funded Industrial Symbiosis projects. However, developing new mines and starting new IS projects in Europe will not solve the huge imbalance of metals in Europe in the short term. To avoid future supply disruptions, like the 2021 Mg crisis, Europe needs to set up a EuropeanEuropean organised stockpile organisation for critical metals like Sc, Sr, Nb, Mg, and Ti.

BauxitesBauxite in the North of EuropeanEuropean Russia are characterized by a high scandiumScandium content (up to 350 ppm calculated as Sc2O3). Most of scandiumScandium is embedded into the structure of aluminumAluminum-containing minerals, as well as into zircon ZrSiO4 and apatite. These minerals break down during the pressure digestion of the bauxitesBauxite, so scandiumScandium is re-precipitated and sorbed on the surfaceSurface of bauxite residueBauxite residue particles. UC RUSAL has developed and pilot tested the extraction of scandium oxideScandium oxide from bauxite residueBauxite residue using a sodium bicarbonate solution that enables to dissolve up to 50% of scandiumScandium into the solution followed by precipitation of the concentrate and purificationPurification to obtain 99.0% Sc2O3. The extraction uses actual liquors from aluminaAlumina production and flue gases. BauxitesBauxite contain a number of REMREM elements (e.g. zircon, titaniumTitanium, hafnium, copperCopper, yttriumYttrium, thoriumThorium, etc.). Chemical behaviour of said REMsREM during the sodium bicarbonate digestion is similar to the behaviour of scandiumScandium. To obtain pure scandium oxideScandium oxide (2N) (Sc2O3 ≥ 99.0 wt.%) without radioactive impurities, effective purificationPurification technology was developed. Moreover, resulting mutual neutralisationNeutralisation of some streams allows obtaining a high-grade REMREM concentrate. The additional advantage of this process lies in reducing the carbon footprintCarbon footprint of aluminaAlumina production due to the use of flue gases containing up to 8 vol.% CO2, as well as alkali neutralisationNeutralisation in the bauxite residueBauxite residue.