Characterization of Minerals, Metals, and Materials 2024

SiliconSilicon (Si) is a versatile alloying element that can enhance the performance of high carbon steelHigh carbon steel by contributing to deoxidation, grain refinement, hardenability, strength, and toughness. The study investigates the influence of Si (0.8–3.6%) on the microstructural and magnetic properties of high carbon steelHigh carbon steel. The arrangement and density of magnetic moments, which are affected by the microstructure determines the saturation magnetisationSaturation magnetisation of the material. Industrial-grade high carbon steel samples with varying silica were microstructurally tailored to obtain multi-phase steel microstructures. The optical and SEMScattering electron microscopy (SEM) analyses revealed a combination of cementite and plate martensiteMartensite, wherein the martensitic structuresStructure became finer with higher Si content. The evolution of martensitic microstructures along with mild oxidation of Si inclusions in the grain boundaries of the surface were observed using Confocal microscopy. An increase in the cementite with an accompanied decrease in the martensitic fraction was determined by the quantitative analysis of the X-ray diffractograms. The saturation magnetisationSaturation magnetisation (MS) of the samples witnessed a gradual decrease with increase in the Si content. SiliconSilicon’s role in high carbon steelHigh carbon steel is quite notable, therefore, the nature of heat treatmentHeat treatment and level of Si addition can be adjusted to limit the formation of cementite and increase the ferritic martensiteMartensite or austenite in the microstructure.

Understanding the transformation mechanism of the viscosityViscosity of the CaO–SiO2–FexO slag is of great significance for improving the quality of liquid steel and ensuring the smooth smelting process. In this study, the viscosityViscosity values of the CaO–SiO2–FexO system at different temperatures were measured, and its meltMelt structureStructure was analyzed by Raman spectroscopy. The microstructure analysis of the viscosityViscosity was then given from the perspective of meltMelt structureStructure. On this basis, a viscosityViscosity prediction modelModel that depends on the concentration of oxygen bonds was established using the molar fractions of oxygen bonds calculated by structural analysis. By comparing the measured and calculated values of viscosityViscosity, it was found that the deviation of all data was within 0.1 Pa s, showing the higher accuracy and stability of the current modelModel.

To enhance the production efficiency of electric arc furnaces, conserve energy, and reduce consumption, a study was conducted to analyze the energy efficiencyEnergy efficiency of electric arc furnace steelmakingElectric arc furnace steelmaking. Through this analysis, an energy efficiencyEnergy efficiency evaluation technology for electric arc furnace steelmakingElectric arc furnace steelmaking was developed. The application of this technology enables the optimization of oxygen supply and power supply systems, leading to improved energy efficiencyEnergy efficiency, reduced power supply time, shortened smelting cyclesSmelting cycle, and achieving cost reduction and efficiency enhancement in smelting processes. An industrial application test was conducted in a steel mill, comparing the results with the original working conditions. The outcomes demonstrated significant improvements. Under normal production conditions, the average values for various parameters are as follows: power supply time reduced by 2.12 min, smelting cycleSmelting cycle shortened by 1.8 min, power consumption decreased by 37.3 kWh/t, power reduced by 0.4 MW, slag composition improved, metal recovery rate enhanced, and improvements in both energy efficiencyEnergy efficiency and chemical energy efficiencyEnergy efficiency were achieved.

A multi-field coupling numerical simulationMulti-field coupling numerical simulation calculates the natural gas flow, combustionCombustion, and gas–solid heat transferHeat transfer processes in a trolley furnaceTrolley furnace using a computational fluid dynamics (CFD) method, coupled with a turbulence modelModel (Realizable k-ε modelModel), a combustionCombustion modelModel (EDC), and a radiation modelModel (DO). This work has investigated the characteristics of components, temperature, and velocity along the axial course of a high-speed burner burning natural gas. The flow field and temperature distributionTemperature distribution of the combustionCombustion flue gasFlue gas in a trolley-type heating furnace are analyzed. The surface temperature distributionTemperature distribution and its internal temperature deviation of a three-slab stack in a trolley furnaceTrolley furnace are studied and the heating uniformity of the slabs is evaluated.

Characterizing viscoelastic polymersViscoelastic polymers is challenging due to their unique combination of elastic and viscous properties. Accurate identification of their mechanical propertiesMechanical properties is crucial for understanding their dynamic behaviour. Traditional methods like creep and stress relaxation tests are time-consuming and require specialized equipment. To address this, a novel inverse technique is proposed in this study for estimating the storage and loss moduli of viscoelastic materials using experimental modal test data. The technique considers a three-layered sandwich structureStructure with isotropic face layers and a viscoelastic core layer. By integrating experimental measurements with mathematical modelling, an iterative process updates material parameters to minimize the difference between modelModel and experimental results. Experimental case studies using dynamic mechanical analysis tests validate the technique, showing accurate estimation of frequency-dependent moduli with < 3% maximum error. This non-destructive and cost-effective approach enables improved material selection, design optimization, and enhanced performance in various engineering applications.

The reduction of chromite oreChromite ore is an important step in the production of ferrochromium alloy and stainless steel. The comparison between conventional and microwave reductionMicrowave reduction of chromite oreChromite ore was investigated in this study with a focus on the effect of reduction time. Compared to conventional reductionConventional reduction, microwave reductionMicrowave reduction of chromite oreChromite ore was more efficient by breaking the stable chromium-containing spinelSpinel structureStructure, improving reduction performance of the ore with generation of large Fe–Cr particlesParticle. By fixing reduction temperature of 1100 °C and C/O molar ratio of 1.2, the metallization degrees of chromium and iron of the briquettes constituted by chromite oreChromite ore and coke after microwave reductionMicrowave reduction increased from 91.57 and 83.03% to 93.53 and 85.78%, respectively, with increasing time from 0 to 120 min, which were higher than those obtained by conventional reductionConventional reduction for 4 h (7.00% for chromium and 67.26% for iron).

In this study, a novel method for simultaneously improving desulfurizationDesulfurization of iron oreIron ore and lowering SO2SO2 emission in flue gasFlue gas at low temperature by microwave roasting of the ore with the addition of urea was proposed. The results showed that the desulfurizationDesulfurization percentage of iron oreIron ore increased significantly with lower SO2SO2 emission in flue gasFlue gas when urea was added. By adding 1.5 wt% ureaUrea into iron oreIron ore and roastingRoasting the mixtureMixture at 250 ℃ for 60 min, the desulfurizationDesulfurization percentage of roasted iron oreIron ore reached 67.37% and the SO2SO2 emission in flue gasFlue gas decreased by 74.68%. After leaching of the roasted ore with water at room temperature for 30 min, the residual sulfur content of the leachingLeaching product decreased to 0.21 wt%. This study provided a good example for efficient, low-cost, and environmentally friendly desulfurizationDesulfurization of iron oreIron ore.

A columbiteColumbite ore of pegmatitePegmatite origin was characterised by subjecting it to energy dispersive X-ray fluorescence (XRF) and diffraction (XRD) analyses as well as scanning electron microscope-energy dispersive spectrometer (SEM–EDS) and Fourier Transform Infra-RedFourier transform infra-red (FTIR) (FTIR) analysis. The sample was pre-concentrated with shaking tableShaking table to upgrade its niobium content. The XRF analysis shows that the ore contains niobium and zirconium at 2.29 and 2.52 wt%, concentrations, respectively. The XRD chart gave prominent peaks at 2θ angles of 27.31, 30.38, 35.79, 38.07, 53.60, 55.92, and 63.70°, which indicate orthorhombic crystal structureStructure of the columbite-iron (FeNbO4) mineral phase. The SEM–EDS spot analyses showed points with Nb, Pt, Si, and Ta having 59.55, 34.03, 33.83, and 16.37 wt% concentrations, respectively. FTIRFourier transform infra-red (FTIR) analysis reveals strong absorption band for Ta and Nb oxides in the regions 1100–1000 cm−1 and 900–800 cm−1, respectively. Shaking tabling pre-concentration increased the Nb assay from 2.29 in the ore to 3.65 wt% in the concentrate.

Efficient and comprehensive utilization of the ludwigite oreLudwigite ore in China has an important strategic significance. However, the significant challenge is the development of highly efficient boron and iron separation process. Soda-ash roastingSoda-ash roasting proves to be a facile approach for boron activation and extraction, wherein magnetite frequently was converted to hematite, which affects the subsequent recovery of iron. This work investigated the phase transformations, microstructure evolutionMicrostructure evolution and magnetism changes of soda-ash roasted ludwigite oreLudwigite ore under different O2 concentrations at 1123 K. Results indicate that Fe3O4 was not obviously oxidized to Fe2O3 but reacted with MgO to form MgxFe3−xO4 and MgyFe1−yO, when the O2 concentration is not more than 5.0 vol%. As the O2 concentration further increased, Fe3O4 was converted to Fe2O3 and MgFe2O4.

CopperCopper–cobaltCobalt calcine leach tailingsTailings material from ChambishiChambishi township of Copperbelt province of ZambiaZambia is refractory in nature due to the presence of copperCopper/cobaltCobalt silicate and residual sulphide minerals. With the aim of solubilizing copperCopper and cobaltCobalt, the material was pre-treated by roastingRoasting in air alone and combination of air and elemental sulphur. As-received material was characterized by XRD and SEMScattering electron microscopy (SEM) techniques. LeachingLeaching without pre-treatment gave poor recoveries (< 45%) for copperCopper and cobaltCobalt. RoastingRoasting of the feed material in air alone had no and little effect on improving leach efficiencies of copperCopper and cobaltCobalt, respectively. On the other hand, copperCopper and cobaltCobalt recoveries of 70 and 80% were obtained after roastingRoasting the feed material with elemental sulphur. The effects of roastingRoasting temperature and dosing of elemental sulphur were studied.

Sintering-blast furnace process is one of the most common methods for treating limonitic lateriteLimonitic laterite. To reduce the negative impact of high aluminum content on the viscosityViscosity of blast furnace slagBlast furnace slag, adjusting the MgO/Al2O3MgO/Al2O3 ratio of sinter is simple and effective. However, the effect of MgO/Al2O3MgO/Al2O3 on the sinteringSintering process of limonitic lateriteLimonitic laterite is still not clear. In this study, the effect of MgO/Al2O3MgO/Al2O3 ratio on the output and quality indexes, phase compositionsPhase composition, and liquid phase content of sinter was investigated detailly. The results indicated that within the range of MgO/Al2O3MgO/Al2O3 of 0.1–0.4, the output and quality indexes of the limonitic lateriteLimonitic laterite sinter showed minimal fluctuations. While the value exceeded 0.4, the liquid phase content in the sinter significantly decreased, leading to a reduction of sinter strength. The MgO contentMgO content in the liquid phase approached saturation after 0.4 MgO/Al2O3MgO/Al2O3, further increasing the ratio would cause MgO to accumulate in spinelSpinel.

To efficiently utilize high-phosphorus oolitic hematiteOolitic hematite, phosphorus should be separated from iron, thus a process of direct reductionDirect reduction and magnetic separationMagnetic separation was proposed. The physicochemical properties of oolitic hematiteOolitic hematite before and after treatment were characterized through analysis of the chemical composition, X-ray diffraction (XRD), scanning electron microscope (SEMScattering electron microscopy (SEM)), and energy-dispersive X-ray spectroscopy (EDS). The influence of various experimental parameters on the upgrading iron and phosphorus removalPhosphorus removal was investigated, including reduction temperature, reduction dose, and reduction time. Additionally, mass conservation was employed to determine the distribution and migration path of phosphorus from apatite to the slag, gas phase, and metallic iron. Results indicated that the optimal experimental conditions for achieving high recovery ratios of metallic iron and high removal ratios of phosphorus were the temperature of 1200 °C, reduction time of 120 min, and C/O molar ratio of 1.2. Under these conditions, 95.28% of iron was collected as metallic iron, while 70.02% of phosphorus remained in the slag residueResidue. Therefore, the proposed method effectively restrained the reduction of apatite, which led to a good separation of iron from phosphorus.

In the 300 t dephosphorization converterConverter, the bottom-blowing O2–CO2–CaOBottom-blowing O2–CO2–CaO technology has been developed and a range of tests executed to optimize the top-blowing parametersTop-blowing parameters. A comprehensive analysis has been carried out on the effects of “tapping temperature T”, “slag basicityBasicity R” and “slag T.Fe content” on the end-point P content, based on data gathered from nearly 2000 smelting operations, using single-factor analysis. Optimal thermodynamic conditions for dephosphorization were obtained, with a tapping temperature of T: 1290–1310 °C, slag basicityBasicity of R > 1.3, slag T, Fe content of 5–10%. The results indicate that dephosphorization ratesDephosphorization rate have increased by nearly 12% under such conditions compared to the original process.

High-purity zinc oxide (> 99 weight %) was obtained from complex zinc silicate ore of Kabwe town of the Central province of ZambiaZambia. The material was leached with sulphuric acid at varying pH to form zinc sulphate. There was partial dissolution of silica during leachingLeaching. The following parameters were studied; leachingLeaching temperature, pH, and solid to liquid ratio. Leach efficiency of 97% was obtained. Zinc was recovered from solution via precipitationPrecipitation with sodium hydroxide, magnesium oxide, and oxalic acid. Low-grade zinc oxide was obtained during precipitationPrecipitation with sodium hydroxide and magnesium oxide owing to co-precipitationPrecipitation of SiO2. On the other hand, there was no co-precipitationPrecipitation of SiO2 during precipitationPrecipitation with oxalic acid such that high-purity zinc oxalate was obtained. The precipitated zinc oxalate was heated up at 500 °C to obtain zinc oxide with purity of more than 99%.

Mold fluxMold flux plays a critical role in absorbing the inclusions floating from the liquid steel. However, this dissolution process is hard to observe in situ because the moldMolds is a “black box”. This paper used the in-situ single hot thermocouple technique (SHTT) combined with high definition microscope to investigate the dissolution behavior of Ti(C,N) inclusionTi(C,N) inclusion in molten CaO–SiO2–B2O3-based mold fluxMold flux, as well as the dissolution mechanism was explored by scanning electron microscope (SEMScattering electron microscopy (SEM)) equipped with X-ray energy spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results suggest that Ti(C,N) inclusionTi(C,N) inclusion was oxidized and then dissolved in molten slag as [TiO4] tetrahedra and [TiO6] octahedra, which is accompanied by the generation of N2 and CO2 gas. In addition, CaTiO3 crystals tend to precipitate and stabilize in the molten slag, leading to the final solid–liquid mixed state of the meltMelt. In addition, the precipitated CaTiO3 crystals are greater in number but smaller in size because the dissolution of Ti(C,N) releases more gases that can provide more nucleationNucleation sites, thereby increasing the nucleationNucleation of the crystal.

As bottom-blowing O2–CaOBottom-blowing O2–CaO converter steelmakingConverter steelmaking process enables rapid slag formation, efficient phosphorus removalPhosphorus removal, and improved steel quality. It has significant strategic significance for the greening and high-quality development of the iron and steel industry. In this study, we collected field actual smelting data, established a mass and energy modelModel, and developed a bottom-blowing O2–CaOBottom-blowing O2–CaO control modelControl model with Visual Studio.NET 2019 (VS2019) as the development tool. The application results indicated that bottom-blowing lime powder flow accuracy is ± 50 kg/min, time accuracy is ± 30 s, and the degree of automation reaches more than 90%. Real-time monitoring allows for dynamic adjustment of the converterConverter's O2–CaO bottom-blowing and accurate control, improving steelmaking production efficiency.

Baking cup experimentsBaking cup experiment were carried out and emission characteristics of SO2SO2 during roastingRoasting of iron ore pelletsIron ore pellets were investigated. Concentration of SO2SO2 starts to increase when the temperature is about 800 °C, then reaches a peak when the temperature is just above 900 °C. Furthermore, emission characteristics of SO2SO2 during roastingRoasting of iron ore pelletsIron ore pellets in travelling grate machinetravelling grate machine were investigated. There are two peaks of concentration of SO2SO2, and the lower peak is in downdraft drying section, while the higher peak is in roastingRoasting section. Concentration of SO2SO2 is at a low level in preheat section, then begins to increase in roastingRoasting section, and reaches peak value in Number 11 wind boxes. Sulfur content in acid pellets is about only one fifth of that in alkaline ones, which might relate to calcium in iron ore pelletsIron ore pellets. Except for chemical compositions, temperature is another important factor for sulfur content in iron ore pelletsIron ore pellets. Sulfur in iron ore pelletsIron ore pellets made from roastingRoasting test was analyzed by XPS, and results show that there is mainly sulfate.

BiocharBiochar is a carbon-neutral fuel that can be used in the iron and steel industry. The reduction behavior of Zn-bearing dustZn-bearing dust using various reductants was compared. Thermodynamic analysis confirmed that the reduction of Fe and Zn followed the carbothermal reductionCarbothermal reduction mechanism. The results indicated that regardless of the reductant used, the Fe metallization and Zn removal achieved a high level of approximately 95% and over 99%, respectively. However, the removal of K showed variability among the reductants, with removal ranging from 55.36 to 92.98%. The Na removal proved to be more challenging, with removal ratios of less than 20% achieved using all the reductants. CSC and BC exhibited higher volatile contents compared to other reductants, and biocharBiochar had a higher reactivity compared to CDQ and TC. The FCad contents of CDQ and TC were higher than other reductants, and FCad was proved beneficial for the removal of K and Na.

Metallurgical grade siliconSilicon (MG-Si) derived from an agricultural wasteWastes rice husk (RH) via metallothermicMetallothermic reduction of pulverized Mg and SiO2 mixtureMixture at ratio 1:1 g was treated and purified by hydrometallurgical purificationPurification process. A low-cost siliconSilicon with high purity was produced by solvent refiningSolvent refining process. In this work, silica of 98.03% has been prepared from rice hulls annealed at 700 °C for 6 h. Furthermore, the silica value was boosted by improved purificationPurification processes to yield 99.51% of silica. The X-ray fluorescence (XRF) showed that several metallic trace impurities were significantly reduced beyond its detection limit. The final process underwent centrifuge of solvent refined siliconSilicon with tin as a selected gettering metal. The X-ray mappingMapping and energy-dispersive X-ray spectroscopy (EDS) quantitative analysis showed that B was eliminated. The XRF of final siliconSilicon powder showed purity > 98.5%.

In this study, purification of rutile ore by leaching using 2–12 mol/L HCl and 2–12 wt% HF was investigated based on the thermodynamic analysis of the main involved reactions and experimental characterizations mainly using chemical titration, X-ray diffraction (XRD), and scanning electron microscopy (SEMScattering electron microscopy (SEM)). It was shown that compared with traditional HCl leachingLeaching, HF leachingLeaching could extract more impurities because of easier reactions between HF and impurity oxides, in spite of minor loss of TiO2TiO2 caused by its reaction with the acid. The purificationPurification performance of both acids increased initially and then decreased with increasing acid concentration. When the ore was leached using HCl with concentration of 6 mol/L at 60 °C for 4 h, the TiO2TiO2 content was enhanced from 95.39 to 97.31 wt% with the highest impurity removal percentage of 41.65%. For HF leachingLeaching, the proper acid concentration was 6 wt%. Under the same conditions as those in HCl leachingLeaching, the TiO2TiO2 content in the ore could be elevated to 98.77 wt% with the impurity removal percentage of 73.32%.

Recycling of graphite anodeGraphite anode from lithium-ion batteries (LIBs) has grown in recent years necessitating the development of advanced characterizationCharacterization methods. It is essential to establish a robust procedure to determine the changes in the crystalline structureStructure, degree of graphitization, and the ratio of the 2H graphite phase to the 3R graphite phase. The distinction between graphite phases has crucial implications for the performance of LIBs. Using X-ray diffraction (XRD), quantitative and semi-quantitative phase analysis methods were employed to determine the structural parameters of graphite, the degree of graphitization, and the ratio of 2H to 3R phase based on the detection of diffraction lines within the 40 and 48° 2θ region. Quantitative XRD analysis of a natural graphite sample using the internal standard method revealed that the relative amount of the 3R phase is 27.18 wt.%. This insight can prove invaluable for industries aiming to optimize the recycling process and maintain high battery performance standards.

Medium-Mn steelMedium-Mn steel has important applications in the lightweight automotive industry due to its excellent comprehensive mechanical propertiesMechanical properties. However, the existence of cumbersome production steps, high energy consumption, and severe macro-segregation seriously limits its industrial development. Hence, this study proposed a green-short method for producing medium-Mn steelMedium-Mn steel with micro-segregation bands using sub-rapid solidificationSub-rapid solidification technology. Exclusive components were designed, and OM, SEMScattering electron microscopy (SEM), EPMA, and EBSD techniques were used to characterize the microstructure distribution, grain orientation, and elemental micro-segregation of the as-cast strips. The phase transformation behavior and formation mechanism of Mn micro-segregationMn micro-segregation during the sub-rapid solidificationSub-rapid solidification process were deeply discussed. This work innovatively utilized the sub-rapid solidificationSub-rapid solidification characteristics to effectively avoid the macro-segregation problem of Mn, and cleverly transformed it into micro-segregation bands that were beneficial for mechanical propertiesMechanical properties. Furthermore, the design of short process provides valuable idea for the industrial production and application of medium-Mn steelsMedium-Mn steel.

Three methods, namely, traditional one-step ball millingBall milling method, two-step ball millingBall milling method, and ball milling-resonant acoustic mixingResonant acoustic mixing method were used for mixing the powders of Ti6Al4VTi6Al4V, hydroxyapatiteHydroxyapatite (HA), and TiB2 before sinteringSintering at 1050 °C for 30 min to prepare boronized Ti6Al4VTi6Al4V/HA composites as dental implants. Their effects on the composition, microstructure, and mechanical propertiesMechanical properties of the composite were investigated. It was found that compared with traditional one-step ball millingBall milling and two-step ball millingBall milling method, the ball milling-resonant acoustic mixingResonant acoustic mixing method led to lower HA decomposition and better TiB2 reactivity during subsequent sinteringSintering process, which contributed to better mechanical propertiesMechanical properties. When the powders were mixed by ball millingBall milling for 12 h, followed by resonant acoustic mixingResonant acoustic mixing for 20 min, the composite obtained after microwave sinteringSintering at 1050 °C for 30 min had good comprehensive properties, namely, compressive strengthCompressive strength of 331.6 MPa, compressive modulus of 8.69 GPa, and Vickers microhardnessMicrohardness of 286.0 HV.

In this study, polypropylene (PP), polyethylene (PE), PP/PE blends containing graphite (1–3 wt.%) and FeO (10–30 wt.%) fillers were prepared using a meltMelt mixing method. The effects of graphite and iron oxide amount on the mechanical propertiesMechanical properties and electromagnetic interference (EMI) shielding efficiencyShielding efficiency in the frequency range of 8–12 GHz (X-band) were investigated. The tensile strength value of the PP/graphite/FeO (1:10) sample increased from 26.09 to 32.47 MPa with the increase of the graphite/FeO amount to 3:30 in wt.%. Maximum total shielding efficienciesShielding efficiency of SET ~ 39.35 dB and 38.31 dB could be observed respectively with a corresponding frequency value of 12.2 GHz for PE and PP polymer mixtureMixture filled with 3 wt.% graphite and 30 wt.% FeO with a thickness of 4 mm. The results obtained from the EMI shielding measurements showed that the total EMI SE increased synergistically with increasing FeO/graphite hybrid filler amount for each polymer composition.

Efficient extraction of nickel and cobaltCobalt from laterite oresLaterite ore is essential for the rapid development of new energy vehicles (EVs). In this work, Ni–Co–Fe powderNi-Co-Fe powder with nickel, cobaltCobalt, and iron grades of 11.98%, 1.18%, and 70.13%, respectively, was obtained from a limonitic lateriteLimonitic laterite ore via rotary kiln reductive roastingRoasting followed by magnetic separationMagnetic separation. The powdery alloy was readily dissolvable in the phosphoric acid solution at atmospheric pressure. From the leachingLeaching solution, amorphous FePO4 · xH2O was precipitated by adjusting pH, and the purified Ni–Co-rich solution could be used for Ni–Co sulfate.

MgO-rich residueMgO-rich residue, consisting of periclase, olivine, and forsteriteForsterite, was generated from ludwigite oreLudwigite ore. This study used MgO-rich residueMgO-rich residue as feed for preparing forsterite-spinel refractory. The phase transformation and physical properties as functions of sinteringSintering temperature and time were primarily investigated. Under optimized conditions of pre-roastingRoasting at 800 °C for 0.5 h and sinteringSintering at 1300 °C for 3 h, a high-quality refractory materialRefractory material with refractoriness of 1700 °C was obtained. This work provides ideas for the comprehensive utilization of ludwigite oreLudwigite ore.

This research explores the chemically bonded ceramicsCeramics and composites, their main advantages, limitations, applications, and structure-material property relations. Particularly, several case studies using calcium silicate and phosphoric acid are presented, mainly applied as a construction or building material, fire protectionFire protections solution, radiation shielding, hazardous wasteWastes stabilization, and even electronics. Scanning electron microscopy (SEMScattering electron microscopy (SEM)) and X-ray diffraction (XRD) results are also shown to understand the microstructure of the cementCements. Results show an increasing trend to use these materials particularly for green construction of small houses, a wave that is expanding in many countries for clients interested in mitigating the pollution and decreasing their carbon footprint. Still, there are limitations in the materials developed, mainly in the durability and stability of the compositions under environmental conditions.

The performance of triply periodic minimum surface (TPMS) lattice structuresStructure was evaluated for use as energy absorbers in automobile crash structuresStructure. Schoen’s Gyroid TPMS lattice structuresStructure were manufactured from colorFabb carbon fibre reinforced nylon (PA-CF) filament using fusion deposition modelling (FDM) 3D printing3D printing. Compressive and energy absorption performance was quantified experimentally using quasi-static compression testing. Test samples were replicated at different gyroid cell size and continuous surface thickness combinations. Results were compared to published data from other lattice structuresStructure to assess relative performance, and analysed to develop a recommended gyroid TPMS geometry. It was determined that varying either the continuous surface thickness, or unit cell size influenced the performance of the structureStructure. A gyroid TPMS structureStructure with a cell size of 10 mm, and a continuous surface thickness of 2 mm was found to perform the best, achieving an impressively high specific energy absorption capacity of 13.06 J/g (± 0.15), significantly outperforming both 3D truss and traditional 2D lattice structuresStructure for use in the automotive industry.

The production of spent lithium-ion batteries (LIBs) is expected to increase rapidly with the rapid development of new energy vehicles. Without proper disposal, the spent LIBs will cause a wasteWastes of resources and a threat to the environmentEnvironment. The route of carbothermal reductionCarbothermal reduction followed by magnetic separationMagnetic separation has been proven to be an efficient process to recover valuable metals from spent LIBs. This paper investigated the reductive roastingRoasting behaviors of the spent cathode materialSpent cathode material under microwave-assisted reductionMicrowave-assisted reduction using biocharBiochar as the reductant. Experimental results show that the chemical phases of spent cathode materialSpent cathode material were converted into Ni-Co alloy, MnO and Li2CO3, wherein Li2CO3 can be extracted by water leachingWater leaching, and the Ni-Co alloy can be recovered by magnetic separationMagnetic separation.

The present study evaluates the suitability of 3D-printed PETGPolyethylene terephthalate glycol (PETG) Double Arrowhead (DAH) auxetic structuresAuxetic structures for increased impact resistance of soft-shell headgear and decreased probability of Mild Traumatic Brain Injury (MTBI), during head-to-ground impacts in sport. A suitable structureStructure should at minimum withstand 30 impacts at 100% likelihood of concussionConcussion and reliably absorb 15 J of energy from a 32 J impact to decrease the probability of MTBI from 100% to ~ 25% with less than 2% total plastic deformation. The peak force, peak acceleration, absorbed energy and cumulative damage of three distinct DAH auxetic structuresAuxetic structures were analysed by quasi-static compression and low velocity blunt force impact tests. The results of this experiment will aid the development of a new headgear technology which reduces the frequency of head trauma as a result of blunt force impact. This decreases the incidence of long-term effects induced by MBTIs.

ZeolitesZeolite are aluminosilicates with porous structureStructure. Due to their cation exchange properties, they are widely used for the treatment of water contaminated with metals. In this research a Mexican expanded perliteExpanded perlite was used to obtain synthetic zeoliteZeolite by the hydrothermal method, the material was characterized by XRF, XRD, FTIRFourier transform infra-red (FTIR), SEMScattering electron microscopy (SEM) techniques. A hydrothermal reactor with a 20 ml PTFE vessel, 1 g of material and 17 ml of NaOH solution were added, then placed in oven. The variables evaluated were NaOH concentration, maintained temperature and time of heating. The type of zeolitesZeolite obtained were zeoliteZeolite Na-P1, cancrinite, sodalite, zeoliteZeolite type A and zeoliteZeolite type Y.

The present study is centered on the biosynthesis of bacterial celluloseBacterial cellulose produced from kombuchaKombucha inoculum, hereafter referred to as kombucha-derived bacterial celluloseBacterial cellulose (KBC). For KBC production, Green tea culture media was utilized. Acetobacter xylinum cultures were obtained from organic apple vinegar and unpasteurized commercial kombuchaKombucha. The resulting KBC was characterized by scanning electron microscopy (SEMScattering electron microscopy (SEM)), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FT-IR) in order to verify its morphological characteristics, thermal resistance, and purity. CharacterizationCharacterization aimed to evaluate the influence of isolation conditions in this region of the world on the physicochemical properties of KBC and determine its potential as a resource for producing biodegradable films.

This paper deals with the evaluation of the potential of the ceramicCeramics soil mass of Itaperuna/RJ, Brazil, to produce pressed ceramicCeramics blocks. The physical analysis indicated that the ceramicCeramics mass presents 37.8% of clay and a density of 2.57 g/cm3. The chemical analysis was done using dispersive energy equipment, presenting high levels of siliconSilicon dioxide (SiO2) and aluminum oxide (Al2O3), these results indicate that the soil has refractory properties. The mineral analysis, performed by means of an X-ray diffractometer, showed the presence of Caulinite, Quartz, Mica Muscovite, and Gibsta, and the first showed higher levels of indication of concentration, plastic characteristic of the sample tested. The ATD and TG curves in the temperature at the firing temperature of most ceramicsCeramics of the Campos dos Goytacazes/RJ CeramicsCeramics Pole, RJ, Brazil, 889 °C, do not identify the presence of thermal transformation peaks. It was concluded that the analyzed ceramicCeramics mass presents viability of use in the production of ceramicCeramics blocks.

Seeking to contribute to reduce the impact of improper disposal of tires on the environmentEnvironment, this article proposes the use of tire rubber as fine aggregate in the production of concreteConcrete. The specimens of dimensions 160 mm × 40 mm × 40 mm were made in the 3:2:1 trace and rubber was used to replace sand as fine aggregate, in the proportions of 5%, 10% and 15% by weight. Compression and flexion tests were performed at 7, 14 and 28 days of cure using a Kratos press, with a maximum cell of 10 tf (98.07 kN), and with a displacement speed of 5.0 mm/min. The results suggest that crushed rubber has restricted use as a substitute for fine aggregate concreteConcrete. At 7 days of curing the best result of mechanical compressive strengthCompressive strength was 19 N/mm2 and for flexural strengthFlexural strength was 5.9 N/mm2 both for 5% rubber replacing fine aggregate.

In the present work, a study of the effect of precipitationPrecipitation on the fracture toughness at cryogenic temperatures was carried out in two austenitic stainless steelsAustenitic stainless steels, nitrogen-containing steel and 316-type steel, after isothermal agingAging. Both steels were solution treated, cold-water quenched, and then aged at temperatures of 600, 700, 800 and 900 °C for times between 10 and 1000 min. The precipitationPrecipitation of these steels was characterized with a scanning electron microscope, and precipitates were analyzed by X-ray diffraction analysis of extracted precipitates, after electrolytic dissolution of austenitic matrix. The fracture toughness of steels was evaluated by the Charpy V-notch impact testing at − 196 °C, and fracture surfaces were observed in a scanning electron microscope. The results showed an intergranular precipitationPrecipitation of carbides M23C6 for both aged steels. However, the kinetics and percentage of intergranular precipitates were higher in the N-containing steel than that in the 316-type steel. The decrease in Charpy impact energy with agingAging time was higher in the N-containing steel and associated with its higher percentage of intergranular precipitationPrecipitation. That is, the N-containing steel is more susceptible to embrittlement due to isothermal agingAging than the 316-type steel. The fracture mode of the aged 316-type steel was transgranular ductile. In contrast, that of the N-containing steel changed from transgranular ductile to intergranular brittle as the agingAging process promoted more abundant intergranular precipitationPrecipitation.

The presence of pyritePyrite in the mineral concentrates of the base metals obtained during flotationFlotation is a common problem; the depressionDepression of these impurities continues under investigation. This paper analyzes the surface state by FTIRFourier transform infra-red (FTIR) of pyritePyrite obtained during collectorlessCollectorless flotationFlotation using several concentrations of ferrous sulfate (FS) as a depressantDepressant. The results found show that the presence of 300 mg/L Fe2+ at pH 6 depresses the pyritePyrite, obtaining a 25% (w/w) cumulative flotationFlotation, at pulp potentials of + 300 mV, while in the absence of FS it is 89.9% (w/w). for all the concentrations analyzed (100, 160, 240 and 300 mg/L) the pyritePyrite flotationFlotation is less than 50%, the pyritePyrite surfaces characterized by FTIRFourier transform infra-red (FTIR) indicate the presence of different species of iron oxides such as akaganeite, lepidocrocite, schwertmanite as well as the presence free sulfate ion responsible for the pyritePyrite depressionDepression.

Effect of hematite concentrateHematite concentrate on pelletizing qualityPelletizing quality was studied. High pressure grinding rollerHigh pressure grinding roller was applied to intensify pelletizing qualityPelletizing quality. The results show that compressive strengthCompressive strength of preheated pellet and roasted pellet decreased significantly when the hematite proportion was 20%. High pressure grinding rollerHigh pressure grinding roller can obviously improve the pelletizing strength, specially preheated pellet. For 40% hematite, the specific surface area of the raw material was increased to 1883.8 cm2/g after high pressure grinding rollerHigh pressure grinding roller. And the drop strength, compressive strengthCompressive strength and busting temperature of the green pellet were 7.0 times/0.5 m, 16.87 N/P and greater than 550 °C, respectively. The compressive strengthsCompressive strength of preheated pellet and roasted pellet were 507 N/P and 3170 N/P, respectively.

In order to improve the output and quality of sinter, the influence of the particleParticle size of the mixtureMixture on the quality of the sinter was studied. The results show that the change trend of the mixtureMixture size modelModel is consistent with the actual mixtureMixture size change trend, and the original size distribution of iron oreIron ore directly affects the final mixtureMixture size. When the average particleParticle size of the mixtureMixture is more than 4 mm, the drum strength and the yield both decrease. When the average particleParticle size of the mixtureMixture is 3.86 mm, the sinter drum strength is the highest, and when the average particleParticle size of the mixtureMixture is 4.08 mm, the sinter yield is the highest. Relying on the comprehensive technical improvement, by reducing the proportion of large-particleParticle iron oreIron ore, the normal and high temperature performance of sinter are comprehensively improved after industrial application. And the sinteringSintering utilization Coefficient is stabilized at about 1.48 t/m2 days, the daily output of the supplied blast furnace can reach 10,000 tons.

The purpose of this study was to evaluate the effects of incorporation of the rice husk ashesRice husk ash (RHA) and titanium dioxide on properties of acrylonitrile butadiene styrene (ABSAcrylonitrile butadiene styrene (ABS)). The incorporation of rice husk ashesRice husk ash (RHA) (RHARice husk ash (RHA)) (2.5 wt.%) and titanium dioxide (2.5; 5.0 wt.%) into ABSAcrylonitrile butadiene styrene (ABS) matrix was carried out by melting extrusion process using a twin-screw extruder. Neat ABSAcrylonitrile butadiene styrene (ABS) and its composites filaments for FDM 3D printing3D printing were produced using the melting extrusion process to obtain specimens for tests. The properties of ABSAcrylonitrile butadiene styrene (ABS)/RHARice husk ash (RHA)/TiO2TiO2 composite samples were investigated by the properties of the ABSAcrylonitrile butadiene styrene (ABS)/RHARice husk ash (RHA)/TiO2TiO2 composite samples were evaluated using tensile testsTensile tests, SEMScattering electron microscopy (SEM), XRD analysis, Charpy impact test, and water contact angle measurements. This study contributes to our understanding of the behavior of ABSAcrylonitrile butadiene styrene (ABS) composites containing RHARice husk ash (RHA) and TiO2TiO2 for various industrial applications.

Portland cementCements is widely used in civil construction, although its production involves the emission of high amounts of carbon dioxide. GeopolymersGeopolymer have been studied as an alternative to replace Portland CementCements. These materials can be produced using wastesWastes and they are less aggressive to the environmentEnvironment. The aim of this work was the physical and mechanical evaluation of geopolymersGeopolymer composites based on red mudRed mud and metakaolinMetakaolin as precursors and sodium hydroxide (NaOH) as activator. Compressive strengthCompressive strength tests were performed in ten mixturesMixture with different percentages of the precursors and sand. The water absorption index and microstructural analysis were also determined. Furthermore, durability tests were performed on the composites, in order to allow complete characterizationCharacterization and suggestions of applicability in civil construction. The results showed that the composites have physical and mechanical characteristics that comply with the standards and good durability performance. Therefore, they can be used to produce construction bricks.

Geopolymeric materials have been extensively studied in science due to their properties similar to Portland cementCements. These materials offer ecological and energy advantages due to their production processes. However, there are costly components that are involved, such as those in the activating solution. Another challenge regarding studies involving geopolymersGeopolymer is the absence of standards, in many cases, an adaptation of those used in Portland cementCements is made. In this context, the objective of this work is to produce geopolymeric metakaolinMetakaolin mortarsMortars and investigate the influence of the volumetric reduction of standardized prismatic and cylindrical specimens compared to cementCements. The goal is to determine whether there is a statistical difference in the properties of mechanical resistance to flexion and compression when using smaller and more economical moldsMolds. The moldsMolds have proven to be efficient and have resulted in significant material savings.

Red mudRed mud is a residueResidue generated in the processing of bauxite for aluminum production and its improper disposal causes significant environmental damage. This study assesses the potential use of red mudRed mud as a pigment in sustainable paintPaints production. The residueResidue underwent deagglomeration, mechanical dispersion, and particleParticle sieving, and was characterized physically, chemically, and morphologically. An experimental mixtureMixture design was employed to evaluate paintPaints performance by varying the proportions of red mudRed mud, water, and resin. Statistical analysis determined the optimal composition as 33% residueResidue, 55% water, and 12% resin. This paintPaints demonstrated an abrasion resistance of 126 cycles and a hiding power of 4 m2/L, meeting the requirements for economic paintsPaints. These findings present a sustainable alternative for utilizing red mudRed mud, contributing to the reduction of environmental harm caused by this residueResidue.

The use of agro-industrial residuesResidue in the production of geopolymeric mortarsMortars has been a point of growing scientific interest not only for gains in mechanical propertiesMechanical properties, but also for sustainabilitySustainability. In this context, natural fibersNatural Fiber stand out for being biodegradable and having lower energy consumption, availability, low density and low cost when compared to synthetic fibers. The natural fiberNatural Fiber from açaíAçaí is an example of agro-industrial wasteWastes generated in large quantities whose disposal is a major environmental problem. Thus, the objective of this work was to produce a metakaolinMetakaolin geopolymeric mortarMortars with the addition of açaí fibersAçaí fibers at 1 and 2% in relation to the mass of the precursor, with fibers not treated and treated with 5 and 10% of NaOH. Then, the samples were tested in the hardened state with resistance to flexion and compression tests and in the fresh state by the Vicat and dropping-ball tests.

The cutting and processing of rocks in the ornamental rock industry have a significant environmental impactEnvironmental impact, resulting in the generation of non-reusable solid wasteWastes that is either directly discarded in nature or sent to landfills. This study aims to assess the utilization of these residuesResidue in ceramicCeramics formulations for brick production. Two types of wasteWastes from different rocks with distinct chemical and physical characteristics were utilized. Physical and chemical characterizationCharacterization tests were conducted on clays and residuesResidue employed in ceramicCeramics manufacturing. CeramicCeramics specimens were produced with varying levels of wasteWastes incorporation, and tests including water absorption, linear variation and flexural strengthFlexural strength were performed. The results demonstrated that the incorporation of both residuesResidue, either individually or combined, enhanced the mechanical propertiesMechanical properties of ceramicsCeramics, with the most notable improvements observed when the residuesResidue were incorporated together.

The role of a firefighter is crucial in safeguarding lives, property, and the environmentEnvironment, as firefighters bravely confront the formidable challenges posed by fires and emergencies. The protective clothing worn serves as a vital barrier, allowing firefighters to operate in extreme conditions while minimizing the risks to their own well-being. This paper characterises a multi-layer material used by NSW Fire and Rescue through cone calorimetryCalorimetry, a powerful fire testing equipment under ISO5660. The multi-layer material was compared with single layer materials used in the 2013 and 2022 Rural Fire Service (RFS) jackets to determine its feasibility to be used by the RFS. Results demonstrated that the time to ignition (TTI) of the multi-layer material, under all heat flux levels, was significantly longer than the two single layer materials. Additionally, it exhibited a lower peak heat release rate (HRR), however, releases greater total thermal energy due to its larger thickness and mass. Both these properties of the material indicate the greater fire resistance of the multi-layer material, but more importantly highlights that this material will allow for an extended time to recognise endangerment and prevent second degree burns.

The difference in metallurgical qualityMetallurgical quality of C-HRA-3 alloyC-HRA-3 alloy smelting using two kinds of slag system was investigated by 10 kg electroslag remeltingElectroslag remelting furnace. The results show that the alloy electroslag ingot smelting by a new-type 50% CaF2-26% Al2O3-20% CaO-3% MgO basic slag system has better surface quality compared to 60% CaF2-20% Al2O3-10% CaO-10% MgO basic slag system. The columnar crystal growth direction of the electroslag ingot, smelting by new-type slag system, has a smaller angle with the centerline, and the depth of the molten pool is greater. The content of Al, Ti, Zr, Si, and B at various positions of two electroslag ingots smelting with the same proportion of TiO2TiO2 and ZrO2 components can be controlled within the target content range of C-HRA-3 alloyC-HRA-3 alloy. There are fewer inclusions in the electroslag ingot smelting by new-type slag system, and the proportion of oxide inclusions at four different ingot heights is lower.

BaTiO3BaTiO3 is generally made by reacting BaCO3 with TiO2TiO2 at a temperature of about 1100 °C. Whatever the technique, the current trend is to produce powders with a strict control of purity, Ba/Ti ratio and particleParticle size, which affects the generation of reproducible microstructures and constant dielectric properties in the sintered product. In this work, the synthesis of solid solutionsSolid solutions of BaTiO3BaTiO3 doped with Eu3+ was carried out and they were synthesized by the solid-state reaction method. The concentration was varied from x = 0.003, 0.05 and 0.10% by weight of Eu3+. The powders were decarbonated at 900 °C and sintered at 1300 °C for 5 h. The experimental results obtained by X-ray diffraction show the consolidation of tetragonal BaTiO3BaTiO3 and the Raman spectroscopy shows the corresponding BaTiO3BaTiO3 spectra that confirm the consolidation in the sinteringSintering process. The scanning electron microscopy results mainly showed particlesParticle with necks characteristic of the sinteringSintering process.

In the present work, rocker arm low AISI 8620 and needle-nose pliers martensitic stainless AISI 420 steelsAISI 420 steel, obtained from melting and gravity casting processes, were analyzed during the homogenizing treatment. The as-cast steelAs-cast steel homogenizing specimens were microstructural and mechanically characterized by optical microscope, scanning electron microscope, and hardness test. In the case of AISI 8620 steelAISI 8620 steel, the observed microstructure was ferrite and carbides with a hardness of 26 HRC. In contrast, the observed microstructure was ferrite and two types of carbides with a hardness of 52 HRC for the AISI 420 steelAISI 420 steel. Both steel specimens were homogenized in the austenite region. The homogenizing temperature was determined using the Thermo-CalcThermo-calc calculated equilibrium pseudobinary phase diagrams. The homogenizing time was obtained by Dictra software. The homogenizing temperature and time were 900 °C and 8 × 104 s (22 h), respectively, for the AISI 8620 steelAISI 8620 steel, and 1040 °C and 7 × 104 s (19 h), respectively, for the AISI 420 steelAISI 420 steel. The results showed that the homogenized microstructure was ferrite, cementite (pearlite), and M23C6 carbides with a hardness of 88 HRB for AISI 8620 steelAISI 8620 steel, and ferrite and M23C6 carbides with a hardness of 43 HRC for AISI 420 steelAISI 420 steel.

Oxide pellets are widely regarded as high-quality raw materials for BF ironmaking and direct reductionDirect reduction iron processes due to their excellent strength, performance and environmental properties. The decrease in the availability of magnetite resources has made the steel industry increasingly relying on hematite pellets. Therefore, understanding the reduction behavior, especially the swelling mechanism, and improving the reduction behavior of hematite pellets in coal-based reduction processes is of paramount importance. In this study, high grade hematiteHigh grade hematite pellets were selected as the raw material, and the basicityBasicity was adjusted for the evaluation of coal-based reduction behavior. The results showed that natural basicityBasicity hematite pellets could achieve a maximum reduction expansion of 55.20%. Increasing the pellet basicityBasicity significantly improved the post-reduction swelling, ultimately leading to normal swelling, with a metallization rate exceeding 94%. Through mineral analysis and microscopic morphology analysis, it was found that an increase in basicityBasicity leads to a denser grain structureStructure, reducing the reaction rate and thus decreasing the strain forces generated during reduction. Additionally, the growth of iron grains results in the formation of a denser iron layer after reduction, further lowering the RSI (Reduced Swelling Index).

Worldwide, galenaGalena PbS is the most abundant mineral sulfide for obtaining metallic lead; however, mineral deposits are frequently associated with impurities that contaminate the concentrate obtained during flotationFlotation, such as pyritePyrite or arsenopyrite. These minerals can be depressed efficiently with the addition of ordinary Portland cementOrdinary portland cement (OCP); however its effect in collectorlessCollectorless flotationFlotation galenaGalena is unknown. In this work, the depressantDepressant action of OPC on galenaGalena flotationFlotation as a function of pH was analyzed. Under highly alkaline conditions pH 12, a % w/w cumulative flotationFlotation of galenaGalena of 71.5 is obtained with a pulp potential of − 44.2 mV, with an electrical conductivity (k) of 1246 μS/cm, the decrease in the alkaline pH of the pulp by adding sulfuric acid depresses the flotationFlotation of galenaGalena, thus, at pH 9 a separation of around 10.81% w/w was obtained, with an oxidizing potential of + 352.2 mV.

Stainless steel has a broad application in various areas of the national economy, while a mass of stainless-steel scraps is generated during the abrasive machining process. These scraps are rich in metallic ingredients such as Fe, Ni, and Cr, which shows an extremely comprehensive recovery value. Due to good plasticity and ductility, the stainless-steel scrapsStainless-steel scraps are hard to grind to fine particlesParticle. The low dissolution efficiency of coarse particlesParticle limits the efficient utilization of stainless-steel scrapsStainless-steel scraps. This work provides a clean and intensifyingIntensifying acid leachingAcid leaching method of Fe, Ni, and Cr from stainless-steel scrapsStainless-steel scraps via ultrasonic treatment. Under the conditions of ultrasound power of 540W, H2SO4 concentration of 3 mol/L, leachingLeaching time of 15 min, temperature of 30 °C, and liquid-to-solid ratio of 20:1, the leachingLeaching efficiencies of Fe, Ni, and Cr are 99.93, 99.91, and 99.92%, which are much higher than those with the conventional leachingLeaching process.

A modelling study was carried out on the melting process of scrap in the Consteel electric arc furnace. By establishing a dynamic melting modelModel based on energy input efficiency and energy balance, combined with the energy input and scrap transport process in the furnace, the melting process and temperature changes of scrap in the furnace were simulated. The accuracy of the modelModel was verified by actual production measurement results. This modelModel shows the effects of scrap transport temperature and speed on the scrap meltingScrap melting rate and furnace temperature during the operation of the steel electric arc furnace, which helps to develop a reasonable operating system for the melting process.

The dredging of harbors is an extremely necessary activity, which is associated with the problem of the disposal of the dredged material, which, even if properly disposed of, affects the environmentEnvironment, not to mention the logistics and disposal costs. Therefore, the present work aims at reducing the extraction of raw materials and reusing the dredging slurry by incorporating the residueResidue into the mortarMortars as a partial substitute for the lime binder. The substitutions were made on a mass base in the mixing ratio of 0, 10, 20, and 30%. The consistency of the mortarMortars was determined using the flow table and checked with the ball test. The squeeze flow test was performed to determine the rheological properties of the mortarMortars. The results were satisfactory, since the binder lime and the dredged slurry have similar granulometry, indicating adequate rheological properties of the material.

In order to investigate the nucleationNucleation process of micro-nano scale droplet in non-equilibrium state, it is necessary to obtain the thermodynamic parameters of rapid phase transition during the solidification process. In addition, the matrix can play a significant role in the solidification nucleationNucleation of the metals. In this paper, the nucleationNucleation process of one single Sn droplet on the surface of Al film was studied by nanocalorimetryNanocalorimetry. The results showed that the surface roughness of Al thin filmAl thin film prepared by magnetron sputtering was about 11.9 nm. With the cooling rateCooling rate increasing from 5 to 10,000 K/s, the undercoolingUndercooling enlarges from 96 to 104 K. However, the undercoolingUndercooling kept nearly unchanged irrespective of the overheatingOverheating extending from 5 to 120 K. In this case, the nucleationNucleation of the Sn droplet is triggered by Sn/Al interface structureStructure, which is nearly independent on the overheatingOverheating.

EAF steelmakingEAF steelmaking process is served as energy intensive fields, which releases massive high-temperature flue gasFlue gas with consumption of extensive raw materials and energies. The effective utilization of wasteWastes heat is essential for energy conservation and emission reduction in the iron and steel industry. Scrap preheatingScrap preheating with flue gasFlue gas is a high-efficiency method for direct wasteWastes heat recovery and utilization. In this paper, the influence of scrap size and arrangement on preheating effectiveness was researched and simulated by ANSYS Fluent 18.2 software. The temperature distributionTemperature distribution characteristics and quantitative values of scrap were further calculated and analyzed. The results indicated that the average temperature of the scrap was higher than 500 °C after continuously being preheated for 15 min by flue gasFlue gas at 1200 °C. This study is beneficial for evaluating scrap temperature before charging to the EAF, and expected to facilitate green, low-carbon, and environmentally friendly development of efficient wasteWastes heat utilization in the EAF steelmakingEAF steelmaking process.

Pure and doped barium titanate powders were prepared by the ball millingBall milling method starting from Barium Carbonate (BaCO3, 99.0%), Titanium Oxide (TiO2TiO2, 99.0%), LanthanumLanthanum Oxide (La2O3, 99.9%), and BismuthBismuth Oxide (Bi2O3, 99.999%). The stoichiometric calculations were made using the Ba1−3xLa2xTi1−3xBi4xO3 mechanism with the concentrations x = 0.000, 0.0025, 0.005, and 0.0075 (wt.%). The powders were mixed in a ball mill with zirconia oxide balls of three different diameter sizes (2.95, 5.05, and 6.48 mm) for 6 h and dried. The powders were sintered at 1200 °C for 5 h; the heating rate was 4 °C/min. The structural evolution of the samples was characterized by X-ray diffraction (XRD) and Rietveld refinement. The analysis of XRD patterns revealed the formation of a well-crystallized tetragonal phase of BaTiO3BaTiO3 (JCPDS 961525438) for the compositions x = 0.0, 0.0025, and 0.005 and the beginning of a tetragonal to cubic phase transition was observed for the composition x = 0.0075.

The Amazon region faces a major obstacle caused by the high production of several natural fibersNatural Fiber, such as açaíAçaí (Euterpe oleracea). There is still no specific and consolidated destination for agro-industrial wasteWastes generated in the different stages of processing Amazonian fibers, causing environmental changes in the region. Furthermore, it is known that the use of these fibers can promote an increase in ductile behavior and tensile strength in cementitious composites. With the objective of contributing to the creation of new strategies that guarantee the improvement of mortarMortars properties and, at the same time, collaborate for an efficient disposal of the wasteWastes in question, this work aimed to evaluate properties of mortarsMortars in the fresh state with the addition of acai fibers. Three types of mortarMortars were developed: (1) reference (without the use of fibers); (2) with the addition of fibers without surface treatment; and (3) with the addition of material with surface treatment based on tannic acid with a concentration of 5% by volume. The fibers were added in the proportions of 0.5, 1.0 and 3.0% in relation to the Portland cementCements mass. From the results, it was verified that there was a reduction in the consistency index and mass density and an increase in the content of air incorporated in the mortarsMortars according to the addition of fibers. Thus, based on these results, the present study seeks to present the alterations of some properties in the fresh state caused by the addition of this natural reinforcementReinforcement.

Barium titanate is an ABO3 type perovskitePerovskite of great interest due to its magnetic, dielectric, piezoelectric, and thermal properties, among others. At room temperature BaTiO3BaTiO3 presents a stable tetragonal crystalline structureStructure. In this work, solid solutionsSolid solutions of the Ba1−3xGd2xTi1−3xEu4xO3 type were sintered by the solid state reactionSolid state reaction method in air at 1300 °C for 6 h with steps of 4 °C per minute with x = 0, 0.001, 0.002 and 0.003. The tetragonal (JCPDS 96-150-7757) and cubic (JCPDS 96-155-9964) phase of BaTiO3BaTiO3 was determined by X-ray diffraction and Rietveld refinement when BaTiO3BaTiO3 was doped. The evolution of the equilibrium of the phases was analyzed according to the increase of the dopantsDopants Eu3+ and Gd3+ and the increase in the stability of the cubic phase of BaTiO3BaTiO3 was determined.

The demand for environmentally friendly products with good performance has grown a lot in recent years. The construction industry generates a large amount of wasteWastes, favoring the production of artificial stonesArtificial stone with properties superior to natural ornamental stones without compromising aesthetics. The objective of this work is to develop and characterize an artificial stoneArtificial stone made with granite wasteGranite waste, from the cutting stages of a quarry, in an epoxyEpoxy resin matrix mixed with cashew oil, ASG-EC. Tests were carried out to evaluate the physical, mechanical, and chemical properties of the stone, in addition to analyzing the microstructure. The ASG-EC presented density (2.21 g/cm3) within the expected range, high values of water absorption (1.02%) and apparent porosity (2.25%), and it is considered of very high resistance with flexural strengthFlexural strength of 23.18 MPa. Furthermore, it proved to be resistant to chemical attacks, showing a change in color only when exposed to C6H8O7, CH3COOH and KOH.

Biobased composites produced from biopolymers reinforced with suitable fillers are an attractive route for producing sustainable materials with improved and diversified properties for a wider range of applications. In this study, biobased composites based on PBAT/PLAPBAT/PLA blend (Ecovio®), kraft ligninKraft lignin, and titanium dioxide (TiO2TiO2) were prepared. First, using gamma-irradiation at 30 kGy, pristine kraft ligninKraft lignin was modified. Then, the pristine lignin, irradiated lignin, and TiO2TiO2 were successfully incorporated into a PBAT/PLAPBAT/PLA blend matrix using a typical melt-mixing process with a twin-screw extruder. Filaments produced by the extrusion process from neat PBAT/PLAPBAT/PLA and its biobased composites were used to obtain parts by FDM 3D printing3D printing. Non-irradiated and irradiated lignin were characterized by ATR-FTIR and XRD analysis. The biobased composite samples were characterized by tensile testsTensile tests, SEMScattering electron microscopy (SEM), and XRD analysis. According to results the incorporation of a small amount of lignin and TiO2TiO2 into PBAT/PLAPBAT/PLA blend and FDM 3D printing3D printing led to obtaining of biobased composites with suitable properties for a wider range of applications.

This study is focused on the detailed investigation of the process mineralogyProcess mineralogy of a typical Vanadium titano-magnetite concentrateVanadium titano-magnetite concentrate (VTM) to efficiently utilize its valuable elements like iron, vanadium, and titanium. The investigation covers mineral phase compositionPhase composition, phase-embedding properties, and the distribution behavior of the main elements of VTM. The phase compositionPhase composition of VTM consists of 84.11% titanomagnetite, 6.52% hematite-limonite, 1.41% ilmenite, 3.87% olivine, and 3.31% alumina. The ore of VTM consists of individual metallic mineral grains and intergrowth grains with diverse structuresStructure and particleParticle sizes. Titanomagnetite is predominantly found in self-formed grain structuresStructure. Hematite-limonite is mainly present in crystalline structuresStructure. It also coexists with titanomagnetite or can be cemented in olivine with a sponge meteorite structureStructure. Ilmenite and magnesium spinelSpinel exist as exogenous crystals within the titanomagnetite. Pyroxene, olivine, silicate, and clay minerals occur in different forms and intergrowths with metallic minerals. Iron and titanium elements in VTM exist mainly in the forms of ilmenite and titanomagnetite, while vanadium elements occur in isomorphism forms within these mineral phases.

In addition to the generation of industrial wasteWastes, especially in the ornamental stones sector, another problem caused by modernization which affects urban lifestyle and the environment is soil sealing. The loss of permeability leads in the surface to an increase in water runoff leading to floods, and through channels, to the transferring of these volumes to nearby water bodies leading to problems like silting up of rivers. The present work has the objective of producing permeable pavementPermeable pavement using gravel wasteWastes in an epoxyEpoxy resin matrix, and analyzing the feasibility of its use with the characterizationCharacterization of its properties. The slabs of permeable artificial stoneArtificial stone were developed with the graniteGranite gravel wasteWastes having a granulometry between 10 and 20 mm. The characterizationCharacterization was made for porosity evaluation through water immersion, determination of the permeability coefficient and mechanical propertyMechanical properties. The results were of an (11 ± 1.7)% void ratio of the artificial stoneArtificial stone, which indicates low porosity, and with a permeability coefficient of 2 mm/s the material can be utilized as a permeable pavementPermeable pavement. The maximum flexural strengthFlexural strength value of 4.26 ± 0.08 MPa, above the 2 MPa determined by the standard minimum, this parameter shows that this permeable pavementPermeable pavement made with artificial stoneArtificial stone has potential to be applied as tiling.

In order to improve technical and economic indexes of ironmaking (BF), metallurgical propertiesMetallurgical property of blast furnace slagBlast furnace slag with low (MgO) were studied systematically based on the laboratorial and industrial tests. The results showed the melting temperature of blast furnace slagBlast furnace slag with 4–7% MgO was lower than 1350 °C under the condition of low Al2O3 content. The viscosityViscosity of the slag met the requirement of blast furnace smelting when the temperature of slag was 1500 °C and the MgO contentMgO content was higher than 3%. The best basicityBasicity of the slag was about 1.245. In the industrial test, the MgO contentMgO content and the viscosityViscosity of the blast furnace slagBlast furnace slag were maintained in the ranges of 4.5–5.0% and 0.16–0.2 Pa s, respectively. The slag with low MgO had good desulfurizationDesulfurization capacity by regulating slag basicityBasicity.

EAF steelmakingEAF steelmaking is characterized by complex charge structureStructure, vigorous chemical reaction, and intensive energy source. The existed disadvantages lead to the big difference of temperature and chemical composition in molten bath, and finally make it difficult for end point controlling. There is still a lack of research on reaction regularity and smelting mechanism in the EAF steelmakingEAF steelmaking process. In this paper, the EAF was divided into “furnace body area” and “molten bath area”. The characteristics of bath fluid flow, elements selective oxidationSelective oxidation, heat transferHeat transfer behavior in EAF steelmakingEAF steelmaking process based on bath stirringBath stirring and multiple input energy were explored and determined through thermodynamic calculation and thermal experiments. The results revealed the reaction mechanismReaction mechanism in the EAF steelmakingEAF steelmaking process based on selective oxidationSelective oxidation, bath stirringBath stirring, and furnace body heat transferFurnace body heat transfer. This research is expected to provide theoretical basis for energy savingEnergy saving and optimization, emission reduction, and green development of the EAF steelmakingEAF steelmaking process.

One of the main complexities of production of a high-quality perovskitePerovskite concentrate at its high recovery (perovskitePerovskite flotationFlotation, as a result of which a perovskitePerovskite concentrate with a content of 49–50% TiO2TiO2 released) is connected with the similar physicochemical and technological (namely, flotationFlotation) properties of perovskitePerovskite, calcite and olivine. Application of high-energy (pulsed-power) technologies in processing of refractory ores enables efficient softening and selective disintegration of finely disseminated mineral complexes, and enhances contrast between the physicochemical and flotationFlotation properties. In this paper, we report the results of experimental studies on nonthermal effect of high-power nanosecond electromagnetic pulses on the surface morphology, structural, physicochemical and flotationFlotation properties of natural perovskitePerovskite from one of the Russia deposit. Using the methods of analytical electron microscopy (SEM–EDX) and microhardnessMicrohardness (Vickers test), we observed the formation of deep parallel microcracks, and the subparallel pyramidal protrusions on the perovskitePerovskite surface. The morphological changes caused a monotonic decrease in the microhardnessMicrohardness of the mineral with an increase of the high-voltage treatment times; the relative change of the microhardnessMicrohardness changed from 20 to 33%. The Fourier-transform infrared spectroscopy (FTIRFourier transform infra-red (FTIR)) data showed that short pulsed treatment times lead to the partial hydration of damaged mineral surface. The electromagnetic pulses perovskitePerovskite pretreatment caused the following changes in the physicochemical properties of the perovskitePerovskite: we made a shift in the electrokinetic potential towards positive values, an increase in the contact angle, as well as the improved adsorption of the collector and the higher flotationFlotation activity of perovskitePerovskite by 10–15%.

Titanium oxide nanoparticles were synthesized by green chemistryGreen chemistry technique, using aloe vera extractAloe vera extract, titanium chloride (2 M, TiCl4) in 1000 mL of ultra-pure water, where aloe vera extractAloe vera extract was added drop by drop and kept with constant agitation of 400 rpm, having a pH ~ 7 with HCl or NaOH. The synthesis product was recovered by centrifugation (10,000 rpm) and washed repeatedly with absolute ethanol. The nanoparticles were washed again with ultra-pure water and dried at 100 °C for 7 h, at the end of drying, a fine white powder was obtained which was characterized by X-ray diffraction, where it was determined that the anatase phase (TiO2TiO2) was obtained, so it has a tetragonal structureStructure, with cell parameters of a = 3.79 Å, c = 9.51 Å. From the synthesis product nanoparticles of sizes ranging from 2 to 30 nm have been obtained, this was confirmed by transmission electron microscopy.

The concern about the amount of solid wasteWastes generated in aluminum production has led to studies on the reuse of this wasteWastes in various types of construction materials. This research investigated the use of red mudRed mud in soil stabilizationSoil stabilization for pavement through alkali activation. Experiments with tropical soil and red mudRed mud activated with NaOH (6, 8, and 10 mol) aimed to optimize the soil propertiesSoil properties. The mixtureMixture was evaluated for mechanical performance, and ideal proportions of mud (10, 20, 30, and 40%) were determined. Compaction curves were performed for different proportions of the residueResidue, obtaining values for optimum moisture content and maximum density. There was an improvement in the strength of the samples with the replacement of up to 20% of red mudRed mud, and it showed a significant improvement, with results exceeding 300%, when compared to compaction without additives.