Journal of Sustainable Metallurgy最新文献

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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A novel greenness and low-cost biosorbent was prepared by polyethylene polyamine-modified waste biomass of sugarcane bagasse in this study, which was used to remove molybdenum(VI) from aqueous solution. The structural properties and adsorption mechanism of this amine-functionalized sugarcane bagasse adsorbent (SCB-A) on Mo(VI) were investigated by SEM–EDS, BET, TG, FTIR, XPS, and batch adsorption experiments. The results show that the adsorption reaction between SCB-A and Mo(VI) was a spontaneous endothermic process, and its theoretical maximum adsorption capacity was about 231.48 mg/g. The adsorption capacity was 8.93-fold compared to that of pristine sugarcane bagasse. This adsorption process was more consistent with the Langmuir model and pseudo-second-order kinetics model, indicating that this process was monolayer adsorption on a homogeneous surface and the adsorption rate was controlled by the chemisorption process. SCB-A possessed great reusability, maintaining a stable adsorption capacity after five recycles. For the adsorption toward Mo(VI), SCB-A also exhibited superior selectivity in a multi-ion coexistence solution. Therefore, SCB-A has tremendous potential in the economically and feasible removal of Mo(VI) from wastewater.

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The lance is the heart of Top-Submerged-Lance (TSL) furnace and is also the most vulnerable part. A numerical simulation model was developed to study the TSL smelting process with a bending lance, and the effects of the bending angle on the flow field, the fluctuation and splashing, and the mean shear on the walls of the lance and the furnace body were analyzed. A VOF multi-phase model coupled with a Realizable k−ε turbulence model was adopted in this work. The simulation results reveal that the bending lance leads to asymmetrical flow field distribution, severer interface fluctuation, significantly higher slag splashing and mean shear stress on the walls of both lance and furnace body. The maximum instantaneous splashing quantity with the bending lances was increased by 33.3% compared to the vertical lance. An improvement by lance rotation on furnace operation was simulated to mitigate the effect of lance bending. Compared with the result of the original vertical lance, a smaller mean shear on the lance wall was achieved for a rotated lance.

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Due to the increased demand and limited supply of nickel, the chromite overburden found in Sukinda Valley, Odisha, can be effectively utilized. This study proposes an alternative method for producing high-quality indurated pellets suitable for direct reduced iron production, which can be further smelted to obtain nickel-based alloys in an energy-efficient manner. Excellent quality pellets from low-grade ferruginous chromite overburden were obtained by optimizing various pelletization parameters, such as basicity values, induration temperatures, and duration. The optimal conditions for producing these pellets were found to be a basicity value of 1.0, an induration temperature of 1300 °C, and an induration time of 10 min. These pellets exhibited excellent metallurgical properties and can be used as a burden for subsequent DRI production. The experimental results were further corroborated by various characterization studies, including X-ray diffraction and scanning electron microscopy coupled with energy dispersion spectroscopy analyses. The study found that the recrystallization of hematite phases during the induration process improved the mechanical strength and various other properties of pellets. However, slightly higher basicity and induration parameters impaired pellet consolidation by creating cracks and forming low-melting slag phases.

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The aim of this study was to optimize the recovery of chromite from the chrome plant tailings of the South African Middle Group chromite seams using a Wilfley shaking table. The optimization process employed the response surface methodology in conjunction with the central composite design. The independent variables considered in the investigation included the tilt angle (°), sample feed rate (g/min), table vibration (Hz), water flow rate (L/H), and particle size range (µm). On the other hand, the recovery (%), grade (% Cr₂O₃), Cr/Fe ratio, and separation efficiency (SE) (%) were determined as the response variables. Based on the characterization results, the sample was identified as a low-grade chromite containing 19.86% Cr₂O₃ and 18.12% Fe₂O₃ with a Cr/Fe ratio of 1.07. The bulk gangue material was well-liberated and rich in MgO (10.45%), Al₂O₃ (12.10%), and SiO₂ (33.70%). The particle size distribution of the sample was 80% passing 106 µm. The optimal values for recovery, grade, Cr/Fe ratio and SE were found to be 71.59%, 36.97% Cr₂O₃, 1.52 and 30% respectively. The corresponding operating conditions were a tilt angle of 5.88°, a sample feed rate of 175 g/min, a table vibration of 44.5 Hz, a water flow rate of 366.16 L/H, and a particle size range of − 106 + 53 µm.

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