Characterization of Minerals, Metals, and Materials 2021

During Al/Cu solid–liquid reactionSolid-liquid reaction, different intermetallic compoundsIntermetallic compounds (IMCs) are expected, which can affect the mechanical and electrical properties of Al/Cu joints. To tackle this challenge, it is then necessary to tune the interface structure, which requires an insight into the formation mechanism of IMCs. In the current study, Al/Cu liquid–solid reaction was used to fabricate different IMCs. With the aid of a focused ion beam (FIB) and high-resolution transmission electron microscopy (HRTEM)High-Resolution Transmission Electron Microscopy (HRTEM), the distribution of IMCs along the Al/Cu interfaceAl/Cu interface was determined. Meanwhile, the orientation relationship among different IMCs and Cu with coherent structure was identified. This study provides a fundamental understanding of the mechanism behind the Al/Cu reaction, which may guide the performance improvement of Al/Cu dissimilar weld.

Single crystalsSingle crystal alloys are a continuous unbroken solid crystal lattice with no grain boundaries. They find a wide range of applications, from semi-conductors, optoelectronics, to applications in aerospace engines. Primary spacingPrimary spacing is a key phenomenon during single crystal solidification as it determines microsegregation, defect formation, and final material performance. In this work, an automatic, standardised, and comprehensive stereological single crystalSingle crystal alloys characterisation methodology is applied to two sections of a CMSX-10® Ni-base superalloy bar. The Shape-Limited Primary SpacingPrimary spacing methodology rapidly and accurately determines dendriticDendritic growth centres, packing pattern, and local primary spacingPrimary spacing distribution within these bulk microstructuresMicrostructure. Using the relationship between the radial variation of local primary spacingPrimary spacing and isotherm curvature, the SLPS methodology has enabled the post-mortem reconstruction of the 3D macroscopic solid/liquid interface shape.

Since the twenty-first century began, environmental concerns related to energetic consumption and pollution have been gaining attention. In part, these could be associated with production and disregard synthetic materials. Using natural materials instead of synthetic aimed to become a trend, which has not happened. Natural lignocellulosic fibers (NLFs) were showed to be capable of replacing synthetic fibers in polymer composites. However, some limitations such as damage from heat can be considered a major constraint for wider application of NLFs/polymer composites. A novel strategy that is suggested to improve this property is the graphene oxide (GO)Graphene oxide treatment functionalization of NLFs. This work investigates the thermal behavior of epoxy/NLF composites, with and without GO functionalization. Two different amounts of reinforcement, low (20 vol%) and high (40 vol%), were dynamic mechanically investigated up to 160 °C. Investigated parameters revealed notable changes attributed to GO-functionalization effect on the NLF regarding viscous stiffness and damping capacity of the composite.

In this work, AlMgB14–TiB2 composite materials were obtained by thermochemical-coupled self-propagating high-temperature synthesis (SHS) and subsequent spark plasma sintering. The phase composition of the raw powder mixture, the obtained SHS product, and the sintered sample was determined. The main phase in the obtained SHS product and the sintered sample is TiB2. The structure of the sample is not uniform. Large TiB2 agglomerates were found. The hardness of the obtained sample is 26.1 GPa.

Ceramic coatingCeramic coating prepared by slurry method has been applied to the metal surface for its excellent properties which can enhance the reliability and durability of industrial equipment. While, for copperCopper as the substrate, a transition coatingTransition coating is needed between ceramic coatingCeramic coating and copperCopper substrate to solve the problem caused by the difference of their thermal expansion coefficients. In this paper, NiCoCrAlY transition coatingTransition coating was prepared by atmospheric plasma spraying (APS) and ceramic top coating was prepared by slurry method. The results show that the transition coatingTransition coating plays a key role in obtaining excellent properties. The thermal shock resistanceThermal shock resistance life at 600 ℃ reached 110 cycles and the bonding strength was 15.04 MPa. The oxidation-resistant effect δ of the ceramic coatingCeramic coating can reach 87.29% at 800 ℃. Thus, the ceramic coatingCeramic coating prepared can be applied to copperCopper equipment for protection against harsh environments.

This work proposes an elasto-plasticElasto-plasticity study of SAE 1045 steel through a stress versus cyclic deformation curve, which was the basis for calculating the material’s hardening parameters, defining the isotropic hardening value as null and kinematic hardening value as 415.05 MPa. Therefore, due to the wide use of SAE 1045 steel in structures and elements that undergo cyclical stresses, the parameters defined in the present work are highly relevant for the analysis of structures based on this material, making it easier to meet the needs during research, diagnostics, or sizing using this steel. The mathematical model used proved to be efficient in generating results compatible with those expected based on the bibliography.

High-carbon steelHigh-carbon steel is one of the typical high-end steels, and its solidification morphology has great influence on the quality of steels. In this work, fractal dimensionFractal dimension was introduced to describe solidification structureSolidification structure morphology in 82B cord steel billet with 0.82 wt% carbon content. Fractal dimensionFractal dimension was calculated using box-counting method (DBox), sandbox method (DSand), and branching method (DBran). It was demonstrated that the fractal dimensionFractal dimension is effective to characterize quantitatively the complexity of solidification structureSolidification structure morphology. The value of fractal dimensionFractal dimension calculated by the above three methods is not the same as different calculation methods describe solidification structureSolidification structure characteristics from different angles. In addition, the relationship between fractal dimensionFractal dimension and secondary dendrite arm spacing (SDAS) and segregation area ratio (Rseg) was discussed. Fractal dimensionFractal dimension calculated by box-counting method was well correlated with SDAS and Rseg. This result demonstrated box-counting method can better reflect solidification characteristics of the billet than sandbox method and branching method.

Zinc oxideZinc oxide (ZnO) thin films are produced by the spray pyrolysis method on glass substrates at 450 °C. The films are characterized using X-ray diffraction (XRD)X-Ray Diffraction (XRD) and UV-VIS transmittance spectroscopy. XRD pattern showed that the films are polycrystalline with hexagonal (wurtzite) structure. Transmittance was measured at room temperature in the wavelength range 350–1100 nm, and used to deduce the absorbance. The fourth derivative of the absorbance is used to detect the peaks in the near-band edge region. Several peaks are found in the region of interest, from which are the free exciton peaks A, B, and C; bound exciton peaks related to defects and impurities; and very weak peaks assigned to longitudinal optical phonon replicas. These results are important for solar cellsSolar cells, room temperature UV laser, and other photonic and optoelectronic applications.

The petrographicPetrographic and SEM-EDSSEM-EDS analysis of Riruwai cassiteriteCassiterite ore located in Doguwa Local Government, Kano State, Nigeria was carried out using appropriate Scanning Electron Microscope (SEM) Microscope and optical microscopeMicroscope. Five representative samples of the ore were taken at intervals 50 m apart, pulverized and thoroughly mixed to give appropriate representation of the entire ore. The results obtained from SEM analysis showed that the cassiteriteCassiterite-bearing minerals are separated from other minerals in the ore by smooth grain boundaries that make it easily to be free from other associated minerals simply by comminution. The petrographicPetrographic study using optical microscopeMicroscope revealed that the cassiteriteCassiterite-bearing minerals contains annite, microcline, cassiteriteCassiterite, and quartz. The petrological analysis results also reveal that the cassiteriteCassiterite structures are in the form of plates and river lines, which are the characteristics of cassiteriteCassiterite. The dark areas are mixture of cassiteriteCassiterite and silicate minerals. Based on the quality of the ore in comparison with cassiterite ores from other parts of Nigeria and based on the results obtained in this research work, it has been suggested that Riruwai CassiteriteCassiterite ore can be a potential source of tin ore as raw material for tin production.

Polymetallic ferruginous manganese oresFerruginous manganese ores contain a variety of valuable metals, it is significant to realize the efficient utilization. Spinel-type composite ferritesFerrites with strong magnetism can be prepared from the polymetallic ferruginous manganese oresFerruginous manganese ores, while the impurities in the ores have certain impact on the properties of the ferritesFerrites. This study was mainly concentrated on the behavior of Al during the formation process of ferritesFerrites. It has been found that during the oxidation roastingRoasting process, Al element has occupied the octahedral gap (sit B) in spinel structure of ferritesFerrites, which reduced the magnetism propertyMagnetism property of ferriteFerrites. However, SiO2 can improve the magnetism propertiesMagnetism property of Al-bearing manganese ferritesFerrites owing to that SiO2 was able to transfer Al out of B sit of spinel via the chemical driving force generated by the formation of corresponding silicates from the SiO2 and Al oxides. This work demonstrated that Al impurity can be regulated by adding SiO2.

Low-grade phosphate ores are the main phosphorus resources in China, and it’s difficult to upgrade owing to most ores belonging to collophanite with fine-grained dissemination. These inferior ores with high silicon and magnesium contents are favorable raw materials to produce fused magnesium phosphate fertilizerFused magnesium phosphate fertilizer (FMP) for the crop growth. However, high temperature of Ca3(PO4)2–SiO2–MgO systemCa3(PO4)2–SiO2–MgO system for the smelting of phosphorite resulted in the energy-extensive consumption. In current study, the effect of K2O additionK2O addition on the smelting of phosphorite was investigated via thermodynamic calculations and experiment validation to reduce the smelting temperatureSmelting temperature. It has been found that 3–5% K2O can reduce the melting temperature of the Ca3(PO4)2–SiO2–MgO ternary system by about 80 °C. Moreover, K2O additionK2O addition can enhance the activities of various nutrients such as potassium and magnesium in the FMP products after smelting and water quenching, and the effective conversionEffective conversion of the nutrients is increased by 5% compared with that without K2O additionK2O addition.

Because zincZinc consumption rises and the high-grade zincZinc ore reserves decrease year by year, the secondary zincZinc resources have been paid close attention. The effect of sulfuric acidSulfuric acid solution on the zincZinc recovery from industrial waste residueIndustrial waste residue was studied in this paper. The results showed that under the conditions of sulfuric acidSulfuric acid concentration of 0.61 M, liquid–solid ratio of 4:1, stirring speed of 400r/min, temperature of 25 °C, and leachingLeaching time of 30 min, the system had a relatively high zincZinc leachingLeaching rate, which reached 86.34%.

Metallurgical solid waste residueMetallurgical solid waste residue contains a certain amount of Zn, which is an important secondary resource for the production of Zn. In this article, a hydrometallurgical method in a NH3–(NH4)2SO4–H2O systemNH3–(NH4)2SO4–H2O system is proposed to recover Zn selectively from metallurgical solid waste residueMetallurgical solid waste residue. The results showed the highest zincZinc extraction of 77.55% was obtained by using a total ammonia concentration of 5 mol/L of the leaching agent, stirring speed of 400 rpm, ammonia/ammonium ratio ([NH3]/[NH4]+) of 1:1, solid/liquid ratio of 1:4, leaching time of 30 min, and leaching temperature of 25 °C.

Coarse sludge (sample A) and fine sludge (sample B) from a Brazilian Linz–Donawitz—LDLinz Donawitz (LD) steelworks integrated plant was characterized. Chemical analysis determined high-level content of iron (51.54–77.53%) and lower grades of zinc (0.49–1.69%). XRD analysis permitted to observe various mineralogical phases, such as metallic iron, wustite, franklinite, magnetite, portlandite, periclase, calcite, calcium oxide, silicon, moissanite-2H, and srebrodolskite. Microscopic Optical and Scanning Electron Microscopic studies shown morphologies of these residues were made up of globular and skeletal aggregates of metallic iron intergrown with crystals of iron oxides, especially wustite and a significant presence of calcite and calcium oxide in spherical nodes having particle sizes between 0.12 and 0.15 mm. Scanning Electron Microscopy–Energy-Dispersive X-ray spectroscopy studies denoted significant content of Fe, O, and Ca in both samples. In addition, a thermogravimetric analysis by DTG–DSC–TG at 1000 °C exhibited a mass loss of 97.43% for sample A and 92.57% for sample B.

In this paper, study on sinter iron oresSinter iron ores and titanium oresTitanium ores used in pelletizing was carried out. Bond work indexes of different sinter iron oresSinter iron ores and titanium oresTitanium ores were measured. Ballability would be improved, and falling strength and compression strength of green pelletsPellet would be increased after fine-grinded sinter iron oresSinter iron ores have been added. High-titanium pelletsPellet with good metallurgical propertiesMetallurgical properties and high compression strength could be produced by using fine-grinded titanium oresTitanium ores. The application of sinter iron oresSinter iron ores and titanium oresTitanium ores used in pelletizing could not only reduce the cost of ironmaking but also expand the iron ore resources for pelletizing.

The environmental pollution caused by steel slagSteel slag accumulation seriously restricts the goal of green and sustainable development in China, and resource utilizationResource utilization is the inevitable trend of metallurgical solid waste. This paper summarizes the advantages and application status of steel slagSteel slag as soil acid–base regulator, agricultural fertilizer, and soil heavy metal curing agent, and puts forward some suggestions on the utilization of steel slagSteel slag in agriculture.

Based on two considerations of making full use of the residual heatResidual heat of V-slagV-slag and exploring a novel green V extraction process, this paper employs MgOMgO as the roasting additive, blows oxygen into the molten V-slagV-slag, and uses the residual heatResidual heat of the V-slagV-slag for pre-roasting at high temperatureHigh temperature. The influence of MgOMgO on the phase structure of V-slags during oxidationOxidation has been investigated by XRD and SEM/EDS. The result shows that MgOMgO as the roasting additive can convert V-slagV-slag at a high temperatureHigh temperature of 1723 K. With the increase of blowing time of oxygen, the trivalent V in the spinel phase gradually disperses in the silicate matrix and then concentrates in the form of magnesium vanadate solid solution (Mg, Mn, Ca)2V2O7. Furthermore, with the increase of MgOMgO content, the peak intensity of the Mg2V2O7 diffraction peak increases significantly. When the MgOMgO content in V-slagV-slag increases from 4.01 to 12.74 wt%, the extraction efficiency increases from 18.99 to 64.07%.

Characteristics and behaviors of primary slagPrimary slag are of central importance for the cohesive zone. This work focuses on phase transformation and viscositiesViscosity of CaO–SiO2–Al2O3–MgO–FeO–TiO2 slag (TiO2 = 4~16 wt%, CaO/SiO2 = 1.1 ~ 1.5, FeO = 5~25 wt%). The melting process of TiO2 bearing primary slagPrimary slag can be divided into three stages. With the increase of binary basicity (from 1.2 to 1.5), the viscositiesViscosity of primary slagPrimary slag are at the same level (above 1674 K), but the Tbr increases 40 K with it. FeO can decrease both viscosityViscosity and Tbr. Tbr decreases to 87 K with FeO content varying from 5 to 25 wt%. When the temperature is lower than Tbr, TiO2-bearing phases (titania spinel and perovskite)Perovskite start to precipitate, leading to the dramatic increase of viscosityViscosity. Tbr increases from 1578 K to 1671 K when TiO2 content varies from 4 to 16 wt%. The effects of TiO2 on FT and Tbr are the same as binary basicity.

Porous pure copper frits were produced by sinteringSintering via both pressure-less and space holderSpace holders methods. Frits function both as a gas pressure release path and radioisotopic fine filter for radioisotopic thermoelectric generators (RTG’s) and radioisotopic heater units (RHU’s). Highly precise and reproducible flow rates are a fundamental requirement in frit vent design, hence accurate characterisation of their morphological structure is crucial. A novel bulk sample characterisation algorithm “GAKTpore” is applied to scanning electron microscope (SEM) maps to study and quantify the effects of processing parameters on sample heterogeneity, pore dispersion, and pore morphology. The purpose of the investigation is to refine the process–property relationships and achieve manufacturable repeatable homogeneous morphological structures. In this study, copper was used as a surrogate for platinum alloys. All frits were tested via a purpose-built/in-house helium precision-flow rig in order to establish a link between permeabilityPermeability and surface morphology. Frits manufactured via the space holderSpace holders route displayed great potential for the future development of the manufacture of frit vents for European RTG and RHU development programs.

Ferronickel slagFerronickel slag, featured by high contents of SiO2 and MgO, is a kind of solid waste produced in the ferronickel alloy process. Proper utilizationUtilization of ferronickel slagFerronickel slag can not only effectively reduce the environmental risk but also realize the high value-added utilizationUtilization. Based on analysis of the composition and phase characteristics of various kinds of ferronickel slagFerronickel slag obtained by different processing methods, the applications of the slag in producing concreteConcrete were discussed for providing insight into efficient use of the waste.

The adsorption materialsAdsorption materials can be prepared from the heavy metal ions flotation sludge in the metal-containing wastewater. When the flotation sludge was pyrolyzed in the air at 800 °C for 4.0 h as a self-template, cubic copper ferrite (CuFe2O4) particle was prepared and tested as an adsorption materialAdsorption materials for the adsorption performance of the material. Structural analysis of the CuFe2O4 particle was performed using scanning electron microscope (SEM), Brunauere–Emmette–Teller (BET), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques. According to the measurement results, the specific surface area of copper ferrite was 10.58 m2/g. The adsorption process of this material for the organic dye methylene blue (MB)Methylene Blue (MB) conformed to the Freundlich isotherm adsorption model and Dubinin–Radushkevitch (D–R) isotherm adsorption models, and it was a multilayer physical adsorption process, which was proven to be an adsorbent with good adsorption performance. The sludge including heavy metal ions was effectively enriched by precipitation flotationPrecipitation flotation, and the recovered sludge is pyrolyzed to form an adsorbent material, thereby achieving the effective utilization of heavy metal resources.

KamafugiteKamafugite is a group of ultrapotassic igneous minerals, alkaline ultrabasic rocks, composed of leucitite, olivine, leucite, kalsilite, and melilite. In Brazil, Kamafugite can be found at Minas Gerais and Goiás state. Based on its composition and the lack of national fertilizerFertilizer production, it would be an alternative source of potassium, phosphorus, and other important nutrients in agriculture. This research analyzed the morphology feature, the physical and chemistry properties of the material, and its potentialPotential as an alternative fertilizerFertilizer. Samples of the KamafugiteKamafugite in natura, supplied by Terra Brazil Minerals, were enriched by the addition of MAP, Elementary S, and Ulexite, being the resulting powder granulated. The materials were analyzed by SEM, EDS, TGA, XRD, Raman spectroscopy, and IPC-AES. The results showed that KamafugiteKamafugite rock is a potentialPotential source of nutrients for plants, once it is composed of K, P, Ca, Mg, Fe, besides Ti. However, is extremely important to analyze the material solubility in water and perform agronomic tests to assure its efficiency.

Steel residuesResidue in general have a high cementing power, which makes them potential substitutes for Portland cement. One of these residuesResidue is that of desulfurization, which currently has no technological application. In this sense, the objective of this work was to evaluate the application of this residueResidue in mortarsMortar 1:1:6:1.5 (cement:lime:sand:water), as a substitute for cement in percentages of 0, 10, 20, and 30%. The tests carried out were consistency, mass density, compressive strength, water absorption, and porosity, in addition to incorporated air content. The results demonstrate that the application of the residueResidue as a cementitious material is possible, due to the good mechanical parameters obtained.

Based on the investigation and study of the topography and composition of the buildups, combined with production process of low-temperature grain-oriented silicon steelLow-temperature grain-oriented silicon steel, the mechanism and major causes of forming buildups of carbon sleeveCarbon sleeve were discussed from the factors such as the quality of carbon sleeveCarbon sleeve, antioxidants, furnace atmosphere, dew point, running speed of carbon sleeve, and so forth. Meanwhile, some countermeasures to reduce the formation of the buildups were proposed.

ArsenopyriteArsenopyrite is a mineral present in most of the world’s mineral deposits, and it pollutes both the environment and base metal concentrates. In this research work, the characterization of arsenopyriteArsenopyrite depressionDepression was studied during collectorlessCollectorless flotationFlotation, in the presence of Al2(SO4)3 and Na2SiO3 mixtures, in a slightly acidic environment. The arsenopyriteArsenopyrite used in this work consists of a single mineralogical phase. The use of 0.1, 0.2, and 0.4 g/ton of the mixture, depresses the presence of this phase in the concentrate by 28% w/w. The percentage of cumulative collectorlessCollectorless flotationFlotation and without depressant reagents was 77% w/w, while in the presence of depressants Al2(SO4)3 and Na2SiO3 it was 49% w/w. The pulp potential Eh (mV) referred to the standard hydrogen electrode, to achieve arsenopyriteArsenopyrite depressionDepression is around Eh + 50 mV.

To mitigate the low environmental performance of civil construction, researchers began to study the incorporation of waste from other industries in construction materials. The aim of this research was to produce and characterize an eco-clinkerEco-clinker from the reuse of grits residues (produced at cellulose manufacturing process), granite residues (produced during the processing of ornamental rocks). To produce the eco-clinkerEco-clinker, three mixtures were formulated considering the parameters of lime saturation factor (LSF), calculation of the Bogue potential, silica ratio (SR), and alumina ratio (AR). The pellets were burnt at a temperature of 1450 ºC for 20 min and then, the mixtures were characterized. The eco-clinkerEco-clinker produced presents large amounts of C2S-β. The mechanical properties in the early ages were out of date. At older ages the mechanical strength of the eco-clinkersEco-clinker can be compared with the mechanical strength of conventional cements.

Ceramic bricks play an important role in the Brazilian economy and have red clay as the basic raw material for this industry. The aim of this study was to discuss the main environmental impacts related to the manufacturing of red clay bricks, comparing the conventional production versus the production of red clay brick incorporated with ornamental stone processing waste (OSPW)Waste. The environmental performance of the production of red clay bricks in Brazil was evaluated with a Life Cycle AssessmentLife cycle assessment study based on the international standards ISO 14040 and ISO 14044. The main impacts of brick production are associated with atmospheric emissions at the stage of extraction and transformation. In both systems studied, the analysis showed relevance regarding the impacts related to human health. This is due to the respiratory effects caused by the clay extraction and burning process, since this step is largely responsible for CO2 and particulates emissions. The mass reduction of the red clay raw material represents a possibility to reduce environmental impacts and improve the sustainability of ceramic bricks, since the bricks incorporated with 5% of OSPW increases the useful life 2.91-fold when compared to the traditional product. The improvement in the estimated useful life of ceramic bricks can reduce the disposal of these materials in landfills, leading to reduction in the environmental impacts.

Various examples of scientific research are promoted in Brazil and in the world to evaluate alternative materials in the industrial process of red ceramicsRed ceramic. Thus, the objective is to reduce the amount of clay by incorporating another material in the production line of the red ceramicRed ceramic parts and consequently to prolong the extraction time of the clay reserves. The ornamental stone industries generate a lot of waste when cutting blocks. The research analyzes the behavior of the flexural strengthFlexural strength of red ceramicRed ceramic parts with the incorporation of these residues. The percentages of waste addition were 0% (0R) 5% (5R) and 10% (10R) by mass. Three firing temperatures were analyzed: 750, 850, and 950 °C. The main objective is, after 175 cycles of wetting and drying, to compare the flexural strengthFlexural strength of ceramic parts with and without the addition of ornamental stone wasteOrnamental stone waste. Flexural strengthFlexural strength was obtained using the 3-point method. According to the results, samples 0R and 10R at all firing temperatures showed lower flexural strengthFlexural strength than samples 5R. The 5R samples sintered at 950 °C were the most resistant with a value of 3.5 MPa after 175 wetting and drying cycles.

The quasistatic compressive behaviour of additively manufactured titanium-carbide (Ti-6Al4-V-C or Ti-C) was investigated through quasistatic compression and microhardness tests. The carbon content within the titanium-carbide samples was varied in order to identify the influence of graphite on the properties of the material. The information gathered through the mechanical tests and optical microscopy was used in order to identify the effectiveness of titanium-carbideTitanium-carbide as a functionally graded material applied in ballistic protection. Initial QS compression testing on 5.3 and 6 wt%C content yielded similar results in mechanical properties. This contradicts the hypothesis which predicts an increase in strength with an increase in carbon content. Further details on the results will be presented in this study.

The replacement of synthetic fibers to natural fibersNatural fibers has been the subject of intense research, particularly as applied in composites. Astrocaryum vulgare is an important palm tree employed for many people along the Amazonian region in handcrafts and other products, by traditional manipulation techniques. The aim of this work is to perform a density Weibull analysisWeibull analysis of Astrocaryum vulgare (Tucum) fibers with different diameters. The results obtained may be a database of Astrocaryum vulgare fibers, helping future research that will address its application potential as an alternative fiber applied in polymer composites.

The objective of this work is to evaluate the replacement of cement and sand by blast furnace slag wasteWaste, in order to produce mortarsMortars with better mechanical properties. MortarsMortars were used 1:3:1.5 (cement: sand: water), with substitutionSubstitution of 0, 10, 20, and 30% of cement by slag. A reference mortar was also produced without the application of the wasteWaste. Cures were evaluated at normal and thermal temperatures at 60 °C and tests were performed on compressive strength, water absorption, porosity, density, and consistency. The results indicate that the slag is viable in the application of both replacing sand and replacing cement.

This study aimed to find the effect of flying ashFlying ash as an additiveAdditive or substitute for cement in compression strengthCompression strength of concreteConcrete blocks (vibro-compacted)Vibro-compacted. For this purpose, a control specimen was manufactured without Portland cement substitution or addition, denominated as the comparison standard with a strength of 6.99 MPa. With this reference parameter, Portland cement was added with 15% flying ashFlying ash, reaching a strength of 7.1 MPa and replaced by three different percentages of the mixture, in proportions of 15, 30, and 50%, reaching strengths of 6.92, 6.4, and 5.07 MPa, respectively. The results showed that the compression strengthCompression strength decreases with increasing substitution percentage; however, at low percentages, flying ashFlying ash can replace Portland cement without compromising compression strengthCompression strength. The physical tests were carried out under the ONNCCE standard. The flying ashFlying ash was characterized using the techniques of scanning electron microscopy (SEM), X-ray diffraction (XRD), and laser particle size analyzer (LPSA).

MgO was considered to be an indispensable mineral composition of the modern sinteringSintering process. Fluidity of liquid phaseFluidity of liquid phase reflecting the scope of effective bonding makes a clear distinction among MgO-bearing fluxesMgO-bearing fluxes in the sinteringSintering process. Mg–Ca combination forms of dolomite, l-dolomite, serpentine and their influence on the fluidity of liquid phaseFluidity of liquid phase and bonding strength of sinter body were investigated and analyzed. The results showed that there were non-separated, partly-separated, and completely-separated states of Mg–Ca in different MgO-bearing fluxesMgO-bearing fluxes. Furthermore, development of the separation degree of Mg–Ca combination statesMg–Ca combination states led to the decrease of Mg content melt in silico-ferrite of calcium and aluminum (SFCA) and increase of Mg content in magnetite. Consequently, fluidity of liquid phaseFluidity of liquid phase was improved due to decline of viscosity of liquid phase. Moreover, bonding strength had a good positive correlation with fluidity of liquid phaseFluidity of liquid phase. Hence, increase of Mg–Ca separation degree was beneficial for improvement of bonding strength.

Considering the thermal shock resistanceThermal shock resistance of ladle lining castable, which is strongly dependent on the phase composition and microstructureMicrostructure, the influence of SiO2 sourcesSiO2 sources on the thermal shock resistanceThermal shock resistance of alumina–spinel castablesAlumina–spinel castables was studied. The results indicate that trace addition of SiO2 was detrimental to the mechanical properties of the samples, due to its acceleration on volume expansion of phase formation and the low-melting phase formed at high temperature. However, the formation of low-melting phase has the potential to improve thermal shock resistanceThermal shock resistance attributed to the loose microstructureMicrostructure stacked by equiaxial plate-like calcium hexaluminate owing to its promotion of ion mobility. Meanwhile, it was also confirmed by the samples with the fused silica because of the maximum retained moduli values and relatively slight influence on high temperature mechanical properties in contrast with other SiO2 sourcesSiO2 sources addition.

Mining industries generate high amounts of tailings, which are usually allocated in dams. These structures cause severe environmental impacts and serious risks to the safety of the surrounding population. Another way to dispose these wastes is the addition into building materials. This work aimed to study the incorporation of bauxite and iron ore tailingsIron ore tailings in clay bricksClay bricks. The raw materials were the tailings and one clay. The mixture design of experiments was applied to obtain the mixtures, and cylinder specimens were produced by pressing. After drying and firing at 950 ℃, the specimens were evaluated for mechanical strength, water absorption, linear firing shrinkage, and apparent specific mass. Based on standards criteria, the optimal mixture was determined containing 40% wt. of clay, 45% wt. of bauxite residue, and 15% wt. of iron ore tailingsIron ore tailings. This study proved the technical feasibility of using high percentages of mining tailings for ceramic production, which is also a sustainable action.

Yellow phosphorus produced by electric furnace is an important raw material for the production of high-purity phosphorus fine chemicals. High temperature of the slag system for the smelting of phosphorite resulted in the energy-extensive consumption. Moreover, the low activity of slag led to the low utilization efficiency. In the current study, the effects of K2O additionK2O addition on the reduction smelting of phosphorite were investigated via thermodynamic calculations and experiment validation in order to reduce the smelting temperature and increase the activity of the slag. It has been found that K2O could reduce the melting temperature of SiO2–CaO–Al2O3SiO2-CaO-Al2O3 ternary system and accelerate the liquid-phase formation. Higher phosphorus volatilization ratio over 97% was obtained when the phosphorite smelted at 1500 °C with binary basicity of 0.8 and 3 wt.% K2O addition K2O addition. Moreover, a K-bearing slag with high activity was obtained and it can be used as micronutrient fertilizerMicronutrient fertilizer.

Açai fiberAçai fiber has a characteristic that enhances its application as a reinforcement material in mortarsMortar. One of the major problems in the use of natural fibers in cementitious composites is the alkalinity of the porous of these materials, which can be solved by applying surface treatmentTreatment to the fibers. The objective of this work was to evaluate four different forms of surface treatmentTreatment of natural Açai fibersAçai fiber, washing them with water, with cyclohexane/ethanol, immersing them in a solution of NaOH or alkaline peroxide, adding them in 4% in relation to the mass of cement in mortarsMortar of cement, and lime for coating. Properties such as consistency, incorporated air content, linear shrinkage, mechanical resistance, and water absorption were evaluated, according to Brazilian standards. The results showed that the treatmentTreatment with alkaline NaOH solution is the one that best managed to modify the surface of the fibers, improving the evaluated technological properties.

In the structural masonryStructural masonry system, the wall performs a structural function, absorbing the loads imposed on the system, being formed by blocks joined by seating mortarMortar. In this constructive method, the quality control of the inputs and the correct dimensioning of the components is of paramount importance. In addition to the inputs, other factors can compromise the strengthStrength of the wall, for example the mortarMortar bedding types. Two types are recommended, full bedding and face shell bedding. In full bedding, the mortarMortar is disposed in all septum of the block. Therefore, this work has the objective of evaluating concrete blocks prismsPrism with two mixed mortarsMortar ratios of different compressive strengthStrength. It is concluded that the increase of the compressive strengthStrength of the mortar influences the increase in the compressive strengthStrength of the prismsPrism with full bedding type.

A solution to mitigate floods in cities is the use of pervious concretePervious concrete pavements. This is a concrete composed of a structure of interconnected voids allowing the flow of water, reducing the speed of surface runoff. Reactive powders concrete, with the addition of coarse aggregate, propitiates the creation of a pervious material combined with good resistance, hardly found in this type of product. The application of thermal curing allows an acceleration of resistance gain in young ages, making the pieces reach the market in less time. Therefore, we sought to study two traces of pervious concretePervious concrete with RPCRPC ratios: 1:4.0 and 1:3.5 gravel in mass, evaluating the resistance behavior by means of thermal curing. Significant gain in compressive strength is achieved in the early ages with thermal curing, and the permeability obtained by both lines analyzed was satisfactory.

Thermoset matrix compounds have been used extensively in several industrial sectors. Many of these applications expose the material in environments that compromise its use, inducing, or agingAging materials of the material. The process involves several simultaneous and apparently independent mechanisms and, therefore, monitoring the evolution of variables within the specified time is an efficient method used to evaluate the behavior of the natural composites in accelerated conditions. Natural lignocellulosic fibers are important, since their use minimizes environmental pollution and the production costs of composite materials. The aim of this work is to obtain the tensile properties of plain epoxy and epoxy-hybrid natural fabricNatural fabrics composite before and after performing aging accelerated by UV radiationUV radiation. The findings of this work reveal that the epoxy-hybrid composite (50 mallow/50 jute) presents a loss in tensile strength at the first 30 min, and the stiffness decreases from the first exposure. Similar to what happens to living beings, polymers and their composites are also susceptible to the action of ultraviolet radiation.

High-temperature spot, air leakage, and even burn out accidents occurred frequently in bellowsBellows of hot blast systemsHot blast system in the metallurgy industry, which seriously affected the stability of the hot blast systemHot blast system and brought hidden danger to safety production. Although coating, grouting, and other treatment measures had been adopted, the effect was very little. Through dissecting and sampling analysis of the failure bellowsBellows, it was concluded that the steel structure of the bellowsBellows had cracking hidden danger due to welding quality defects, and other reasons for the failure were high temperature of the bellowsBellows steel structure caused by hot air channeling. Therefore, it was proposed that not only the steel structure material and design but also the performance and quality of the internal refractory material of the masonry should be paid attention so as to ensure the air tightnessAir tightness. Only by combining these two aspects can the service life of bellowsBellows be effectively improved.

MagnesiteMagnesite and its main associated mineral dolomiteDolomite are with a small floatability difference because of similar crystal structure and surface properties, which results in low flotation recovery of magnesiteMagnesite from dolomiteDolomite. In order to solve the problem, a new mixed collectorCollector of sodium oleate (NaOL) for magnesiteMagnesite was proposed in this paper. The effects of flotation behaviorsFlotation behaviors of magnesiteMagnesite and dolomiteDolomite were investigated by flotation experiments, and the mineral wettability was characterized by contact angle testing. The results show that the mixed collectorCollector could greatly reduce the hydrophobicity of dolomiteDolomite and improve the floatability difference between magnesiteMagnesite and dolomiteDolomite. The Gaudin’s selectivity index of two minerals increased from 1.75 to 3.78.

Industrial waste incorporation in artificial stoneArtificial stone production has been widely used nowadays, both in search of alternative raw materials as well as for seeking an environmentally correct destination for the waste. During ornamental stones processing, material losses are significant, generating wastes that are often inappropriately disposed of in nature. Quartzite is classified geologically as a metamorphic stone, composed almost entirely of quartz grains and porcelain powder and is characterized by a dense microstructure, consisting of mullite and quartz crystalline phases. The main aim of this work is to characterize and evaluate the effects of incorporating quartzite, quartz, and porcelain powder wastes in an epoxy matrix for artificial stoneArtificial stone development. Plates were produced by the vacuumVacuum vibro-compression method, already adopted by companies in this field. The highest density mixture was calculated, and the artificial stoneArtificial stone developed was characterized to evaluate its physical and mechanical properties. The two most close-packed mixtures were used to produce the plates. The absorption values obtained for the two compositions suggested the artificial stoneArtificial stone can be used in external environments, tops, and floating/raised floors, due to the water absorption index ≤0.4%. The composition in which the porcelain powder was incorporated obtained maximum bending stress of 25 MPa, classifying the artificial stoneArtificial stone as high quality to be applied as a coating.

The use of modifying admixturesModifying admixture in cement-based composites is mandatory to improve their physical properties with technical and economic advantages. This paper discusses the influences of an alternative admixture based on linear alkyl benzene sodium sulfonate (LAS)LAS in cement pastesCement pastes. Rheological tests were carried out on a flow table. Setting times and reaction speed were evaluated by ultrasonic pulse velocity (UPV) measurements. Compressive strength tests were performed in mortars. Different LASLAS contents were evaluated (0, 0.01, 0.1, and 1.0% by cement mass). Contents of up to 0.1% of LASLAS did not significantly change the rheological behavior in comparison to the reference paste, whereas the content of 1.0% of LASLAS showed a clear plasticizer effect. The highest levels of LASLAS resulted in an acceleration in the setting times, which contrasts with the results of UPV. Contents of 0.01 and 0.1% did not impair the strength in the first ages.

AdherenceAdherence is one of the main properties of rendering mortarsMortar. Pathologies related to the lack of adherenceAdherence between the mortarMortar and the ceramicCeramic block are frequently seen, especially on facades. A complex system with several variables influences adherenceAdherence, where the sorptivity of the ceramicCeramic block can be highlighted. The objective of this work is to verify the influence that the sorptivity of the ceramicCeramic block has on the mortarMortar adhesion in different combinations. CeramicCeramic blocks burned at three temperatures with and without the presence of roughcast were used. The ceramicCeramic blocks were evaluated by immersion absorption, mechanical strength, and sorptivity tests. Three traces of mortarMortar were used, characterized by water retention and mechanical resistance tests, in addition to adherenceAdherence with the ceramicCeramic block. The adherenceAdherence results between the materials indicated that the sorptivity influences the adherenceAdherence with different behaviors, depending on the mortarMortar used.

The ornamental rock industry generates an enormous amount of waste on manufacturing process. Granite Graniteis the main rock extracted in Brazil for export blocks, a country that is one of the largest exporters in the world. The expressive volume of powder generated during the manufacturing process can be reused in the manufacture of ceramic Ceramicpieces. The objective of this work is to evaluate three different particle sizes of the waste and its influence on the ceramicCeramic block sorptivity Sorptivitycapacity. The clay used in the work and the residue were characterized by chemical analysis test, granulometry, Atterberg limits, and grain density. After the production of ceramic Ceramicpieces with three levels of incorporation (0, 10, and 20%) of the residue, immersion absorption, sorptivitySorptivity, mechanical resistance, and adherence tests with mortar were carried out. The results indicate that the granulometry of the residue significantly influences the sorptivity Sorptivity of the ceramicCeramic.

The reuse of granite wasteGranite waste in the manufacture of building paintsPaint is an alternative studied to contribute to sustainable development. Therefore, the objective of this study is to evaluate the influence of granite wasteGranite waste, acting as mineral filler, on the weathering resistanceWeathering resistance of soilSoil pigment-based paintsPaint. To manufacture the paintPaint samples, a mixture design of experiments was defined, varying the proportions of soilSoil (pigment), granite wasteGranite waste (mineral filler), and polyvinyl acetate resin (binder). On the other hand, the water (solvent) was varied in each mixture, in order to keep a constant paintPaint viscosity. The weathering resistanceWeathering resistance test was performed based on the specifications of ASTM G7:2013. A weekly monitoring was carried out to identify the appearance and development of pathological manifestations in the paintPaint films. The color variation was quantified by the delta-E method. The paintPaint film submitted to weathering was compared with the paintPaint film protected from external agents. It was observed that the use of granite wasteGranite waste in soilSoil pigment-based paints delays the appearance of pathological manifestations and reduces the color change of the product. Thus, it is possible to conclude that granite wasteGranite waste has a strong potential to be reused in the production of paintsPaint.

During the production of geopolymeric materials a great challenge exists when it comes to the process of dosing and mixing the constituents, called activators and precursors. In addition, these materials have a great potential for incorporating different solid waste. The objective of this work was to evaluate the different ways of mixing the constituents of the geopolymerGeopolymer materials, evaluating the influence of these variations in the mixing process, molding and curing temperature of the mixtures, and incorporating the glass wasteGlass waste as an activator of the mixture with a molar ratio of 3.5. Prismatic specimens were made and properties such as mechanical resistance to flexion, linear shrinkage, and water absorption were evaluated for each condition evaluated. It can be concluded that the order of insertion of the components in the mixture, as well as the molding mode and cure temperature directly influence the technological properties of the specimens.

The physical properties of a large-scale stock pileStock pile of iron ore were in situ investigated during its stacking and reclaiming processReclaiming process. The total weight of the stock pileStock pile was around 200,000 tons. The stacking and reclaiming processReclaiming process lasted for 480 h. The tested physical properties included angle of repose, size and shape data, size distribution of the blending ore, and so on. At the initial stage of the stacking processStacking process, the angle of repose was 37.1°. A decreasing trend was observed as the stacking processStacking process proceeded. In vertical direction, particles at bottom are much coarser than that at upper layer. In longitudinal direction, the head and tail Sect. (5.7 m in length) of the stock pileStock pile showed serious particle segregation. According to the testing results during the reclaiming processReclaiming process, the deviation of the particle sizeParticle size deviation at the cross section of the stock pileStock pile was above 10%.

The particle size of imported iron ores has gradually become bigger, which is adverse to mineralization and reaction in sinteringSintering process. At present, only imported iron ore fines are used in Jingtang sinteringSintering plant. And it is hard to control the particle size of imported iron ores. Different iron ore fines are mixed properly before charged to sinteringSintering machine. It is an important means to solve this problem to seek the particle size matchingParticle size matching between solid fuel and iron ore fines. The suitable matching mode of fuel particle size (d) and blending ore particle size (D) is as follows: d/D = 0.47 ~ 0.54. When the particle size of blending ore changes, the fuel particle size should be controlled according to d/D with fuel crushing process. Since the matching mode was applied, the main quality indexes of sinter improved obviously. The return fine rate of sinter decreased from 25.43 to 24.64%, and the solid fuel consumptionSolid fuel consumption decreased from 44.8 to 43.9 kgce/t.

Natural fiberNatural fibers-reinforced polymer (NFRP) composites have obtained significance in recent times due to their wide application in different industries, such as automotive, aerospace, construction, home appliances, and ballistic vest because of the high cost of synthetic fibers and environmental issue. These natural fibersNatural fibers are cheaper and lighter but their mechanical properties are lower than the synthetic fibers. In addition, great efforts have been made to understand the phenomenon of weathering of polymeric materials, which ultimately result in the deterioration of the physical and mechanical properties of the polymer. This work aims to present some research in the degradation area of natural fibersNatural fibers and their composites. The components of NFRP and flexuralFlexural test strength and modulus are revealed in the first part. Afterwards, the second part will be devoted to review some methods of aging treatments applied to natural fiberNatural fibers composites. Eventually, a discussion about the optimal approaches for lifetime prediction of NFRPs will be drawn.

The structural masonryStructural masonry has as basic characteristic the use of the supporting walls, formed with structural blocks joined by seating mortarMortar. The blocks must have compressive strength compatible with the loads to which they will be subjected to, and the mortarMortar must be adequately resisted in order not to compromise the structure of which it is part of, and absorb the deformations to which the masonry is subjected. Two types of mortarMortar bedding are recommended: full bedding, covering net area for unit, and face shell bedding, where the mortarMortar is placed only in the face shell area of the block. This work aims to test the compression of face shell bedding concrete blocks prismsPrism with two traces of mixed mortarMortar with different compressive strength. It has been concluded that the increase of the compressive strength of the mortarMortarinfluences the increase in the compressive strength of the prismsPrism with face shell bedding type.

TheAlkali activated materials main pathogens that occur in alkali-activated materials based on blast furnace slagSlag are efflorescence and the black heart, due to the saturation of very high amounts of sodium. Therefore, the objective of this work was to measure the alkali mortars activated by a solution of 2.5, 5, 7.5, 10, 12.5, and 15M using sodium hydroxide, testing the material under compression and water absorption with 7 days of curing at room temperature, and thermal curing at 60 °C. The results show that the use of 12.5M and 15M causes the appearance of this pathologyPathologies when curing in a normal environment, while compositions with 10M, 7.5M, and 5M present excellent technological parameters.

Civil construction is in constant search for alternatives to reduce the degradation of the environment and, therefore, studies new materials technologies that are sustainable. MortarMortar is an example whose raw materials involve a high commercial value and highly energetic production processes in relation to CO2 emissions. This work compares embedded clayClay mortarsMortar for use in wall and ceiling coverings. These are two claysClay: a clayClay from Campos dos Goytacazes-RJ and an industrialized clayClay collected from local businesses. For this purpose, characterization of the aggregates, study of the mortarMortar dosage, consistency indexes, water retention tests, specific gravity, compressive strength, and tensile bond strength were carried out. The results indicated that Campos clayClay tested as a material for dosing mortarMortar in wall and ceiling was compatible with industrial clayClay, allowing the commercialization of the studied product.

The pH is a critical variable and influences the surface state of the float mineral particles and the flotationFlotation efficiency. JamesoniteJamesonite is a sulphosal of lead and antimony with iron content Pb4FeSb6S14. In this research, the study of the surface state of jamesoniteJamesonite was carried out by means of infraredInfrared spectroscopy of particles obtained in flotationFlotation without a collector in acid, neutral and alkaline medium. In an alkaline medium, the flotationFlotation of the mineral decreases or is depressed, mainly due to the oxidationOxidation of the surface iron forming iron oxyhydroxide, α-FeOOH goethite, considered as a hydrophilic species, as well as the division of the main sulfate band indicating the formation of metal sulfates. Meanwhile, when the flotation Flotationis carried out without a collector at pH 5.9 and 7.8, a 70% w / w recovery is achieved, and the absorption bands of the covalently bonded species are significantly attenuated.

The presence of copper aqueous (+2) in the pulps that feed the flotationFlotation circuits is due to the oxidation of the copper contained in sulfides (chalcopyrite) and in oxides (malachite) as a result of the galvanic reactions that occur during grinding copper aqueous (+2) can have a negative effect during the collectorlessCollectorless flotationFlotation of galenaGalena. In this investigation, the galenaGalena concentrated by collectorlessCollectorless flotationFlotation and in the presence of copper aqueous (+2) in alkaline media was superficially characterized by infraredInfrared spectroscopy. The results show the depression of galenaGalena with the increase of the dosage of copper aqueous (+2) in the pulp at pH 9.6 and Eh of +120 (mV). From the infraredInfrared characterization, it was found that the surface state of the galenaGalena when it undergoes depression, shows the absence of some of the absorption bands corresponding to the Pb-O and Pb-OH bonds of lead oxide and hydroxide detected when galenaGalena flotationFlotation reaches maximum recovery.

Owing to suffering the poor recovery of valuable metals and the massive loss of Co metal by the traditional pyrometallurgical technology to process the low-nickel matte. Herein, a sulfate roasting followed by a water leachingWater leaching process was developed as an efficient technology for the simultaneous extraction of Ni, Cu, and Co from low-nickel matteLow-nickel matte in the presence of (NH4)2SO4 additive. The influence of roasting temperature, the dosage of ammonium sulfateAmmonium sulfate, and roasting rules on the leaching efficiency of metals are conducted. Also, the characterizations of phase evolution are complemented with the theoretical analysis of thermodynamic calculation to reveal the mechanism of (NH4)2SO4 added sulfate roasting. The results demonstrate that the (NH4)2SO4 plays a critical role in reducing the reaction temperature and improving the metal selectivity, achieving higher extraction efficiency of Ni, Cu, and Co (90.12%, 81.82%, and 92.45%, respectively), while Fe is only 10.18% and the high selectivity extraction can be achieved.

Zinc oxide nanoparticlesNanoparticles were synthesized using the green chemistry technique, zinc acetate was used as a precursor agent and Schinus molleSchinus molle extract as a stabilizer agent the main Schinus molleSchinus molle component are carboxylic acids, similarly presents tension bands of the C-H group, the S-O group. A white powder, characteristic of zinc oxide, was obtained. X-ray diffraction was performed on the synthesisSynthesis product and identified as zincite (ZnO), with a compact hexagonal unit cell, whose network parameters are at a = 3.2490 Å and c = 5.2070 Å, the ICDD-PDF letter is 96-901-1663. Scanning electron microscopy characterizationCharacterization showed that the nanoparticlesNanoparticles have a spherical morphology, sizes ranging from 23 to 67.6 nm.

The correct disposal of tires is a major concern for the environment. A part of the waste is used to manufacture rubber asphalt, providing environmental, technical, and economic advantages. In the present work, it was identified that the permanent deformation at 60 °C in 10,000 cycles for CAP 50/70 (traditional asphalt) is 4.7%, while rubber asphalt is 2.5%. In addition, the permanent deformation at 60 °C in 30,000 cycles for CAP 50/70 is 6.2%, and for rubber asphalt, it is 3.2%. Thus, the pavement with rubber asphalt is more durable compared to the pavement with CAP 50/70. So, even though rubber asphalt is a little more expensive, in the end, it becomes more economical because it has greater durability. Moreover, over the years the CAP 50/70 will need more maintenance, while rubber asphalt promises a much lower amount of maintenance.

The aim of this work is to evaluate the possibility to use textile residuesTextile residues of polyamidePolyamide with elastane that are discarded by the industry as a matrix of a new polymer-clayClay composite material, evaluated on a manometric scale, and to propose a way of recyclingRecycling for these materials. At the same time, with nanocomposite technology, value is added to this material. In this work, polyamidePolyamide of textile residuesTextile residues from industry was used. These materials were first processed in a compacter machine. Composites at 1, 2, and 3% by weight of Light Green clay/polyamidePolyamide were prepared by double screw extrusion. The properties of the composite were characterized by X-ray diffraction (XRD), tensile, flexural, impact tests, and thermogravimetric analysis (TGA). Results obtained were compared with the neat textile polyamidePolyamide properties. It was concluded that it is feasible to recycleRecycling the textile residuesTextile residues of polyamidePolyamide, and that the addition of clayClay, at the doses studied in this work, could lead to the obtaining of composite materials with better mechanical than untreated ones.

Ladle furnace slags and fly ashes may be utilized as soil stabilizers in road construction as an option to reuse these by-products. However, there is no method grounded on experimental design to optimize the dosage of those by-products in mixtures with soil. This study applied the Simplex-LatticeSimplex-lattice method to perform the experimental design to optimize the design of soil-slag-fly ashFly ash mixtures. The soil was geomechanically characterized and the by-products were subjected to scanning electronic microscopy (SEM), X-ray diffraction (XRD), pozzolanic activity, and specific surface area analysis. The experimental mixtures were submitted to an unconfined compressive strength test and the results led to a response surface and a mathematical model that described the interaction between the components and allowed the mixture design optimization. This study highlights the potential of the Simplex-LatticeSimplex-lattice method to optimize soil-slag-fly ashFly ash mixtures and the technical suitability of utilizing those by-products as soil stabilizers.

The dosage of activated alkali materials, as is the case with blast furnace slagSlag mortars, is one of the great complexities of materials science. In this context, the objective of this work is to propose the mortar dosage 1: 1: 0.5 (precursor: aggregate: activator), varying the silica moduleSilica module of the solution by 0.3, 0.6, 0.9, 1.2, and 1.5, and performing compression, density, water absorption, and porosity tests, performing thermal curing at 60 °C and normal curing, with curing of 7 days. The results showed that the variation of the silica moduleSilica module significantly changes the results of the evaluated properties, with the best parameters obtained for a 1.2 module of silica.