Journal of Sustainable Metallurgy最新文献

This study explores the isothermal hydrogen reduction of sintered pellets made of a mixture of bauxite residue and calcite with varying compositions at different reduction temperatures. Sintered pellets with varying compositions show three primary iron-containing oxide phases including brownmillerite, srebrodolskite, and fayalite; however, brownmillerite is the major phase in all the sintered pellets. The sintered pellets were reduced in a thermogravimetry furnace to establish instantaneous weight reduction with respect to time. Phases and microstructural analysis were carried out using X-ray diffraction and scanning electron microscopy, respectively. Mercury intrusion porosimeter and pycnometer were utilized to assess the porosity and density of the reduced pellets. Thermochemistry calculations were performed using the thermodynamics software FactSage 8.2. The reduction rate is most pronounced at a temperature of 1000 °C for all pellet compositions. It is intriguing to note that the rate of reduction shows minimal variance across pellets with different compositions; however, the higher calcite pellets exhibit a higher initial rate of reduction. Various kinetic models were examined to determine the activation energies for three different composition pellets, and the three-dimensional diffusion model has been well suited for this process. Close activation energies in the range of 84.6 to 94.8 kJ were obtained. A slightly higher activation energy was obtained for lower CaCO₃ added pellets, and it was attributed to their reduced porosity and increased sintering, impeding the reaction kinetics. There were no significant differences in the formation of mayenite with varying the calcite amount; however, higher calcite pellets indicated more mayenite formation.

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End-of-life lithium-ion batteries (LIBs) are waste from electric vehicles that contain valuable and critical metals such as cobalt and lithium in their composition. These metals are at risk of supply due to the increase in demand in the manufacture of technological products and the concentration of reserves in specific countries. When we talk about urban mining, the step of separation and purification is difficult and crucial for development of technology to recover metals because there are many problems when we have a mix and different concentration of these metals. Thus, this study aim is to clarify the techniques used in the recovery of LIBs residues for the NCA type. The NCA-type batteries, which contain, in addition to lithium (Li), cobalt (Co) and nickel (Ni), the element aluminium (Al) in their cathode structure. It is observed was carried out on the recovery of LIBs of all types, and a gap was observed regarding NCA type. Although many studies cover the recovery of metals in cathode structures from LIBs, it is not observed for batteries containing Al. Its observed that aluminium is a problem for the separation process because of its chemical characteristics. Based on this analysis, the recovery of metals presents in the NCA type batteries, the route proposed is that the first step should be the precipitation of aluminium, followed by solvent extraction of cobalt, and the last step is the precipitation of nickel, followed by lithium precipitation.

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Biochar from seaweed, specifically sugar kelp, cultivated on the Norwegian coastline has been investigated as a possible biocarbon source for the metal industry to reduce the dependency on terrestrial biomass. Pre-processing of the biomass prior to pyrolysis is needed to reduce the water and ash content and was performed by water and acid washing followed by drying. The three types of biochar were obtained after pyrolysis at a temperature of 550 °C. Characterization of the three batches of biochars showed that pre-processing of the seaweed as was done during the water and acid washing, plays an important role on the removal of ash content. Due to the enormous amount of woody biomass needed for example in the ferroalloy industry to replace fossil coal, replacing only parts of the woody biomass with kelp biochar could have a significant impact. Water washing combined with acid washing had the best results considering the ash and fixed carbon contents. Microstructural analysis of the seaweed biochars showed a very porous material with the crystal structure resembling that of charcoal, albeit a lower degree of crystallinity.

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The burgeoning accumulation of vanadium-titanium magnetite tailings (VTMT) presents a dual challenge of environmental hazard and loss of valuable metal resources. This review arrives at a crucial juncture in global efforts towards a circular economy, focusing on innovative and effective metal recovery technologies. We explore the forefront of recycling methodologies, including suspension magnetization roasting, chlorination roasting, hydrometallurgical methods, and emerging approaches like MnO₂ roasting, magnesia and calcium roasting, and microwave oxidation roasting. Our analysis juxtaposes these advanced methods against traditional techniques, emphasizing their superior environmental and resource recovery benefits. Despite promising advancements, these technologies are still in nascent stages, each presenting unique merits and limitations that necessitate further research. This paper delves into the future trajectory of VTMT recycling, emphasizing the integration of technological innovation with environmental and resource stewardship. By tackling the specific challenges of VTMT, we underscore the urgency for holistic, efficient, and eco-friendly solutions. The future of VTMT metal recovery hinges on the progressive refinement and amalgamation of these technologies, underscored by a commitment to balancing ecological concerns with societal demands.

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It is crucial to control the sulfur and oxygen in the steel liquid to produce high-cleanliness rare earth steel. This study attempted to investigate the effect of rare earth Ce content on purifying the produced 7CrSiMnMoV steel from scrap steel by modified rare earth inclusions based on a proposed integrated process of high-alkalinity refining slag desulfurization, Si–Mn deoxidation, Al-enhanced deoxidation, and rare earth Ce alloying. The results show that the evolution mechanism of rare earth inclusions is 25% Al₂O₃⋅25% MgO⋅50% Ce₂O₃ → 25% Al₂O₃⋅75% Ce₂O₃, 12.5% Al₂O₃⋅MnS⋅Ce₂O₂S → Ce₂O₃, Ce₂O₂S → Ce₂S₃, Ce₂O₂S → (Mn Ce)₂S₃, Ce₂O₂S, with the rare earth Ce-added content of 0.009%, 0.012%, and 0.100%, respectively. And rare earth Ce can improve the cleanliness of steel liquid by controlling the rare earth Ce-added content to form the M1-Ce₂O₃ (M1 is Al, Mg, etc.) and M2-Ce₂SO₂ (M2 is Ca, Mn, etc.) rare earth inclusions; the oxygen and sulfur concentrations can reach 0.0031% and 0.0026%, respectively, with a rare earth Ce content of 0.012%. However, excessive amounts of rare earth Ce could deteriorate the cleanliness of steel liquid.

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To produce 7CrSiMnMoV rare earth steel by scrap steel based on an integrated process of high-alkalinity refining slag desulfurization, Si–Mn deoxidation, Al-enhanced deoxidation, and rare earth Ce alloying and purifying steel liquid.Purifying 7CrSiMnMoV rare earth steel liquid by modified rare earth inclusion.Rare earth Ce can improve the cleanliness of steel liquid by controlling the rare earth Ce-added content to form M-Ce2O3 (M is Al, Mg, etc.) and M-Ce2SO2 (M is Ca, Mn, etc.) rare earth inclusions; the oxygen and sulfur concentrations can reach 0.0031% and 0.0026%, respectively, with a rare earth Ce content of 0.012%.

This study focused on determining the optimum conditions for the maximum recovery of base and precious metals from printed circuit boards of end-of-life desktop computer motherboards using Taguchi-based grey relation analysis. In the first stage of the two-stage study, optimum conditions were investigated for the dissolution of base metals (copper and zinc) in waste printed circuit boards under high-pressure leaching. The dissolution of base metals was performed based on the L25 orthogonal array designed by Taguchi method. In the second step, designed according to Taguchi L9 orthogonal array to recover gold and silver from the solid remaining from the pressure-leaching process. Optimum combinations of parameters in both stages were determined using the multi-criteria optimization technique grey relationship analysis. In the experiments carried out in the determined optimum combinations, 99.62% of copper, 98.76% of zinc, 99.15 of silver and 85.82% of gold in waste printed circuit boards were recovered.

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The presence of cadmium (Cd) in ternary batteries is a known detriment to both their service longevity and cycling performance. Traditional methods for reducing Cd levels in cobalt (Co) sulfate solutions can be effective but often result in significant losses of Co. This study introduces an enhanced dual-extractant system that combines 5% (V/V) di-2-ethylhexyl phosphoric acid (P204) with 5% (V/V) bis (2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex301) to effectively lower Cd content without substantial Co depletion. Conducted at a pH of 1.8 with a 1:1(V/V) organic-to-aqueous phase ratio at 25 °C for 10 min, our approach achieved a 99.99% extraction efficiency for Cd and limited Co extraction to just 0.53%. Subsequent stripping processes utilized 1 M sulfuric acid and 6 M hydrochloric acid to recover 87.13% of Co and 95.11% of Cd. An efficient process roadmap operated at optimized condition was demonstrated for plant-wide treatment of the cobalt sulfate solution containing Cd. The innovative results hold the potential to accelerate advancements in secondary resource recycling, especially Cd and Co.

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High-pressure acid leach (HPAL) residue from laterite nickel ore is a potentially valuable resource for ironmaking; however, its efficient utilization is hindered by its high sulfur content. In this study, an effective and straightforward method is proposed for sulfur removal from HPAL residue. The process involves sieving and sodium carbonate leaching, enabling significant sulfur reduction from 5.12 to 0.81% and simultaneous enrichment of iron content from 47.12 to 55.27%. The sulfur content in the treated HPAL residue falls below the permissible level for the ironmaking industry, rendering it suitable for use as a low-grade iron ore. This innovative approach not only facilitates the valuable utilization of HPAL residues but also mitigates solid waste emissions, addressing the economic and environmental challenges associated with large stockpiles of solid waste.

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The synergistic extraction law of vanadium and gallium from Bayer mother liquor by OH⁻ type LSC-600S resin was investigated in this paper. More than 72.21% of vanadium and 74.46% of gallium were adsorbed from Bayer mother liquor, when the conditions were resin of 4 g/L, adsorption time of 100 min, temperature of 70 °C, and stirring rate of 500 r/min. Thermodynamic calculations show that the extraction of vanadium and gallium by the resin proceeds spontaneously, and that an increase in temperature favors the extraction of vanadium and gallium. Theoretical research results showed that, the kinetics of adsorption process followed the pseudo-second-order reaction, and the adsorption isotherm followed the Freundlich isotherm model. The infrared spectrum analysis results showed that, gallium ions in solution interacted with the C=NOH in the resin, and vanadium ions interacted with the C=NOH and C–NH₂. The synergistic extraction of vanadium and gallium does not reduce the adsorption capacity of the resin for gallium, but also effectively recovers vanadium. It provides a new method for the recovery of vanadium resources from Bayer mother liquor.

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Hydrogen can replace partially pulverized coal in the blast furnace injection as the clean and high-calorific energy, which can reduce energy consumption and carbon emission in molten iron production. In this study, a discrete phase model is used to describe the complex flow and thermochemical behavior associated with the co-injection of hydrogen and pulverized coal in the raceway. The effect of hydrogen injection rate on the raceway is studied from the aspects of gas velocity, temperature, concentration distribution and coal burnout rate. It can be concluded that with the hydrogen injection rate increases, the gas velocity slightly increases and the gas temperature decreases significantly at the deeper location of the coke bed. With the hydrogen injection rate increase every 10 m³·t⁻¹, the theoretical combustion temperature decreases about 14 K and the amount of gas in the bosh increases about 46.91 m³. When the hydrogen injection rate increased to 50 m³·t⁻¹, the coke ratio is reduced by 8.66%, and the concentration of CO and hydrogen along the axis of tuyere increases by 0.5% and 7.79%, respectively. However, when the hydrogen injection rate exceeds 30 m³·t⁻¹, the pulverized coal burnout rate decreases.

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