Journal of Sustainable Metallurgy最新文献_第9页

Effect of Particle Size and Starch Gelatinization on the Mechanical and Metallurgical Performance of Jarosite Plus Blast Furnace Sludge Self-Reducing Briquettes 粒度和淀粉糊化对 Jarosite Plus 高炉污泥自还原砖机械和冶金性能的影响

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-05-01 DOI: 10.1007/s40831-024-00825-2

G. Dall’Osto, D. Mombelli, V. Trombetta, C. Mapelli

Jarosite and blast furnace sludge (BFS) are two of the main wastes from hydrometallurgical zinc production and iron production by blast furnace, respectively. Jarosite is a hazardous material that can, however, be reused in the steel industry after the recovering of the iron contained within it through carbothermal reduction in which BFS is exploited as a reducing agent. Yet, both wastes have a powdery nature that makes it necessary to agglomerate them for industrial use. On the other hand, despite the advantages of producing a self-reducing product, the particle size of the starting powders and the level of gelatinization of the binder could play a crucial role on the mechanical and metallurgical performance and, consequently, on the industrial applicability of the briquettes. Accordingly, two powder particle sizes (very fine sand vs. coarse silt) and three degree of corn starch binder retrogradation (10%, 30% and non-gelatinized starch) were used to produce briquettes, and their influence was studied by experimental and statistical investigation. The results showed that gelatinization plays the main role on the mechanical properties of briquettes, while particle size affects both density and reduction behavior; in particular, although all the mixtures were able to recover iron at 950 °C the most optimal mixture were obtained by using a granulometry of 63–125 µm for jarosite and less than 63 µm for BFS, while the local maximum of mechanical performance was obtained for a 30% starch retrogradation level.

Graphical Abstract

铁石棉和高炉污泥（BFS）分别是湿法冶金锌生产和高炉炼铁产生的两种主要废物。铁石棉是一种危险材料，但在通过碳热还原法回收其中所含铁之后，可重新用于钢铁工业，而高炉污泥则可作为还原剂加以利用。然而，这两种废料都具有粉末状的性质，因此必须将其团聚起来才能用于工业用途。另一方面，尽管生产自还原产品有很多优点，但起始粉末的粒度和粘合剂的胶化程度对压块的机械和冶金性能以及工业应用性都有至关重要的影响。因此，我们采用了两种粉末粒度（极细砂和粗粉砂）和三种玉米淀粉粘合剂胶化程度（10%、30% 和非胶化淀粉）来生产煤球，并通过实验和统计调查研究了它们的影响。结果表明，糊化对压块的机械性能起主要作用，而粒度对密度和还原行为都有影响；特别是，尽管所有混合物都能在 950 °C 下回收铁，但使用粒度为 63-125 µm 的硬质合金和小于 63 µm 的 BFS 可获得最佳混合物，而 30% 的淀粉还原度可获得机械性能的局部最大值。

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引用次数: 0

Comparing the Microstructural Changes of Mechanically Activated Hematite During Nano Zero-Valent Iron Preparation 比较纳米零价铁制备过程中机械活化赤铁矿的微观结构变化

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-30 DOI: 10.1007/s40831-024-00830-5

B. N. Akhgar

This investigation presents a new method for preparing nano zero-valent iron (NZVI) from mechanically activated hematite. The XRD analysis indicated that even after 240 min mechanical activation (MA), the constituent phase of hematite could be detectable without any phase change. Regarding peak broadening and reduction of peak intensity, MA generally changed the microstructural properties of hematite with more intensity during the first 60 min of intensive planetary ball milling. The microstructural study performed by the Rietveld method also proved that all microstructural parameters changed in favor of the reactivity promotion of hematite. The amorphization degree and microstrain were increased to 83% and 0.16 (%), respectively, while crystallite size was reduced to 9.2 nm after 240 min MA. Therefore, MA could promote the hematite leachability where iron extraction was increased from 14% in initial hematite to 61% in 240 min mechanically activated hematite. Leaching efficiency increased even after surface area reduction and agglomeration in 240 min mechanically activated hematite. Consequently, the surface area parameter would not be the main factor in hematite reactivity promotion, as microstructural parameters changed in favor of hematite reactivity during MA. Among the microstructural parameters, the amorphization degree and crystallite size were the predominant parameters in the reactivity promotion of 60 min mechanically activated hematite and replaced with microstrain after 240 min MA. Also, NZVI was synthesized with titrating NaBH₄ through chemical precipitation from the iron-bearing solutions obtained during mechanically activated hematite leaching tests. The XRD and FE-SEM analyses also revealed that NZVI was synthesized and fairly oxidized.

Graphical Abstract

这项研究提出了一种利用机械活化赤铁矿制备纳米零价铁（NZVI）的新方法。XRD 分析表明，即使经过 240 分钟的机械活化（MA），赤铁矿的组成相仍然可以检测到，没有发生任何相变。在峰值扩大和峰值强度降低方面，MA 普遍改变了赤铁矿的微观结构特性，在高强度行星球磨的前 60 分钟，峰值强度更大。用里特维尔德法进行的显微结构研究也证明，所有显微结构参数的变化都有利于赤铁矿反应性的提高。MA 240 分钟后，非晶化度和微应变分别增加到 83% 和 0.16 (%)，而晶粒尺寸则减小到 9.2 nm。因此，MA 可以提高赤铁矿的浸出率，铁的提取率从初始赤铁矿的 14% 提高到 240 分钟机械活化赤铁矿的 61%。即使在 240 分钟机械活化赤铁矿的表面积减少和团聚之后，浸出效率也会提高。因此，表面积参数并不是促进赤铁矿反应性的主要因素，因为在机械活化过程中，微观结构参数的变化有利于赤铁矿反应性的提高。在微结构参数中，非晶化程度和晶粒大小是促进 60 分钟机械活化赤铁矿反应性的主要参数，而在 240 分钟 MA 之后则被微应变所取代。此外，从机械活化赤铁矿浸出试验中获得的含铁溶液中通过化学沉淀滴定 NaBH4 合成了 NZVI。XRD 和 FE-SEM 分析也表明，NZVI 已合成并被相当程度地氧化。

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引用次数: 0

Slag-Hanging Capacity of Numerical Simulation and Analysis of Blast Furnace Copper Cooling Plate Based on ANSYS ‘Birth–Death Element’ 基于 ANSYS "生-死元素 "的高炉铜冷却板数值模拟和分析的挂渣能力

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-26 DOI: 10.1007/s40831-024-00818-1

Zhen Zhang, Jue Tang, Mansheng Chu, Quan Shi, Chuanqiang Wang

At present, there were two main problems with the cooling plate slag-hanging: One was that the research on the slag-hanging mechanism of cooling plate was not deep, and the other was that the calculation process of the slag layer thickness with cooling plate was unreasonable. Based on ANSYS ‘birth–death element,’ a slag layer iterative cycle calculation method was designed, and the change of slag layer under different boundary conditions was analyzed. The gas temperature increased from 1200 to 1600 °C, and the slag layer decreased from 56 to 8 mm. When the gas temperature was 1550 °C, the copper cooling plate would exceeded safe operating temperature (120 °C). The thermal conductivity increased from 1.2 W·m² °C⁻¹ to 2.2 W·m²·°C⁻¹, and the slag layer was able to be thickened by 76–85%; however, the slag layer would became non-uniform. When the temperature of slag-hanging increased by 50 °C, the slag layer increased by about 6.9 mm-7.6 mm, and the uniformity of slag layer increased by 10%. The maximum temperature of cooling plate could be reduced by 5°C–10°C when the cooling water speed increased by 1 m·s⁻¹. The cooling water temperature was reduced by 10 °C, and the maximum temperature of cooling plate and the measuring point temperature could be reduced about 10 °C. The above research and analysis provided a basis for the blast furnace to have a reasonable operating furnace type and a longer life.

Graphical Abstract

目前，冷却板挂渣主要存在两个问题：一是对冷却板挂渣机理研究不深，二是冷却板渣层厚度计算过程不合理。基于 ANSYS 的 "生灭元素"，设计了一种渣层迭代循环计算方法，并分析了不同边界条件下渣层的变化。气体温度从 1200 ℃ 上升到 1600 ℃，渣层从 56 mm 下降到 8 mm。当气体温度为 1550 ℃ 时，铜冷却板将超过安全工作温度（120 ℃）。导热系数从 1.2 W-m2 °C-1 增加到 2.2 W-m2-°C-1，渣层厚度增加了 76-85%，但渣层变得不均匀。当挂渣温度提高 50 ℃ 时，渣层增加了约 6.9 mm-7.6 mm，渣层的均匀性提高了 10%。当冷却水速度增加 1 m-s-1 时，冷却板的最高温度可降低 5℃-10℃。冷却水温度降低 10 °C，冷却板最高温度和测量点温度可降低约 10 °C。上述研究和分析为高炉拥有合理的操作炉型和更长的使用寿命提供了依据。图文摘要

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引用次数: 0

Development of Sodium Silicate-Activated Ground Granulated Blast Furnace Slag and Fly Ash Binder-Based Concrete for Pumping Applications 开发用于泵送应用的硅酸钠活性磨细高炉矿渣和粉煤灰粘结剂混凝土

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-18 DOI: 10.1007/s40831-024-00822-5

Aparna Sai Surya Sree Nedunuri, Salman Muhammad

Alkali-activated materials are one of the alternative cementitious materials, but their extensive usage is constrained by certain limitations, such as quick setting and rapid loss of workability. By addressing these limitations, this study developed alkali-activated concrete formulations, with enhanced workable times and pumpable workability, comprising of precursors based on fly ash and blast furnace slag. The precursors were activated with sodium silicate activator of molar modulus 1.5 and activator dosage (% of Na₂O) of 8 and 10%. Zinc sulfate was incorporated as a retarder to prolong the workable times. The spread diameter of these concrete mixtures measured at 10th min was in the range of 650–745 mm. Several of the developed concrete mixtures could retain the spread diameters in the range of 430 – 655 mm for a duration longer than 90 min. These developed alkali-activated concrete mixtures with pumpable workability and prolonged workable times have exhibited compressive strengths in the range of M30 to M60 grade. The rheological behavior of these concrete mixtures was also assessed on their corresponding concrete equivalent mortar (CEM) mixtures. The yield stress and plastic viscosity of CEM mixtures were found to decrease with an increase in the proportion of fly ash and increase with an increase in the hydration time and retarder content. The evolution of yield stress and plastic viscosity of alkali-activated CEM mixtures were found to be in agreement with the obtained spread diameter values for concrete mixtures.

Graphical Abstract

碱活性材料是一种可替代的胶凝材料，但其广泛使用受到某些限制，如凝结速度快和工作性损失快。针对这些局限性，本研究开发了碱活性混凝土配方，由基于粉煤灰和高炉矿渣的前驱体组成，具有更长的工作时间和可泵送工作性。前体使用摩尔模量为 1.5 的硅酸钠活化剂进行活化，活化剂用量（Na2O 的百分比）分别为 8%和 10%。硫酸锌作为缓凝剂加入，以延长可施工时间。在第 10 分钟测量的这些混凝土混合物的铺展直径范围为 650-745 毫米。有几种开发的混凝土混合物可在超过 90 分钟的时间内将铺展直径保持在 430 - 655 毫米的范围内。这些开发的碱活性混凝土混合物具有可泵送性和较长的可工作时间，抗压强度在 M30 到 M60 级之间。这些混凝土混合物的流变行为也在其相应的混凝土等效砂浆（CEM）混合物上进行了评估。发现 CEM 混合物的屈服应力和塑性粘度随着粉煤灰比例的增加而降低，随着水化时间和缓凝剂含量的增加而升高。碱活化 CEM 混合物屈服应力和塑性粘度的变化与混凝土混合物的铺展直径值一致。

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引用次数: 0

Silane Gas Production Through Hydrolysis of Magnesium Silicide by Hydrochloric Acid 通过盐酸水解硅化镁生产硅烷气体

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-17 DOI: 10.1007/s40831-024-00817-2

Azam Rasouli, Raphael Kuhn, Samson Yuxiu Lai, Jafar Safarian, Gabriella Tranell

Monosilane (SiH₄) is a common precursor for the production of high-purity silicon for solar PV applications. As an alternative to carbothermic reduction of silica to produce metallurgical grade silicon with subsequent conversion to silane, an alternative route over magnesiothermic reduction of silica to Mg₂Si has been explored in our earlier work. In the current work, silane gas production through hydrolysis of Mg₂Si in HCl acid solution was studied. Two sources of Mg₂Si were chosen: a commercial Mg₂Si source and a Mg₂Si source produced through magnesiothermic reduction of high-purity natural quartz. Effects of various parameters on the hydrolysis of Mg₂Si, including different experimental setups, temperature of the acid solution, acid concentration, reaction time, and relative amounts of reactants were studied. The evolution of produced gases was determined by two different methods: firstly, by passing the produced gas through a KOH solution to capture Si with subsequent analysis of the Si content in the KOH solution by inductively coupled plasma mass spectrometry and secondly, on-line gas analysis by GC–MS. The silane distribution between different silane species with reaction time was evaluated and the activation energy of silane formation was calculated. The results indicated comparable silane yields obtained from the on-line GC–MS method and KOH solution analysis method, as well as for commercial Mg₂Si and the Mg₂Si–MgO mixture produced through magnesiothermic reduction. Furthermore, adding HCl acid to Mg₂Si in water led to higher SiH₄ formation yield than adding Mg₂Si to acid. However, the total silane yield for the two methods was similar at approximately 32%.

Graphical Abstract

单硅烷（SiH4）是生产太阳能光伏应用所需的高纯度硅的常用前驱体。作为碳热还原二氧化硅生产冶金级硅并随后转化为硅烷的替代方法，我们在早期的工作中探索了镁热还原二氧化硅为 Mg2Si 的替代路线。在目前的工作中，我们研究了通过在盐酸溶液中水解 Mg2Si 来生产硅烷气体。我们选择了两种 Mg2Si 来源：一种是商用 Mg2Si 来源，另一种是通过镁热还原高纯度天然石英产生的 Mg2Si 来源。研究了各种参数对 Mg2Si 水解的影响，包括不同的实验设置、酸溶液的温度、酸浓度、反应时间和反应物的相对数量。通过两种不同的方法测定了生成气体的演变情况：第一种方法是将生成气体通过 KOH 溶液以捕获硅，然后通过电感耦合等离子体质谱法分析 KOH 溶液中的硅含量；第二种方法是通过气相色谱-质谱法进行在线气体分析。评估了不同硅烷种类之间的硅烷分布随反应时间的变化情况，并计算了硅烷形成的活化能。结果表明，在线气相色谱-质谱法和 KOH 溶液分析法以及商用 Mg2Si 和通过镁热还原法生产的 Mg2Si-MgO 混合物的硅烷产率相当。此外，向水中的 Mg2Si 中加入盐酸会比向酸中加入 Mg2Si 产生更多的 SiH4。不过，两种方法的总硅烷产率相似，都约为 32%。

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引用次数: 0

Carbothermal Reduction of Oil Shale Residue (OSR) in DC Electric Furnace to Prepare Si–Al–Fe Alloy 在直流电炉中碳热还原油页岩渣（OSR）以制备硅-铝-铁合金

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-15 DOI: 10.1007/s40831-024-00826-1

Yang Qu, Hongjie Luo, Zekun Zhi, Jinbo Qiao, Linli Wu

The growing scarcity of conventional oil resources has intensified the focus on shale oil, known for its abundant reserves. Nevertheless, in the process of shale oil retorting, a substantial quantity of harmful waste oil shale residue (OSR) is generated. In this study, OSR and bituminous coal sourced from Fushun City served as the raw materials for the production of Si–Al–Fe alloy in a DC electric arc furnace, proposing a novel way to efficiently utilize OSR. The experiment summarized and analyzed the current oxide reduction theory, combined with the actual experimental results, focused on investigating the phase transformations of OSR during the reduction process. Based on the gaseous suboxide-carbide reaction theory, the reduction mechanism of pellet raw materials at high temperature was proposed. Results showed that the pellet raw materials will first undergo high temperature decomposition during the reduction process, and generated a large amount of carbides. Carbides subsequently reacted with metal suboxides produced in the high-temperature zone of the electric arc furnace to yield alloys. The element distribution of the obtained alloy product was non-uniform, the metallic Si phase was closely adjacent to the SiC substance, and the Fe in the alloy significantly enriched the reduced Al and Ti elements.

Graphical Abstract

传统石油资源的日益匮乏使人们更加关注储量丰富的页岩油。然而，页岩油在蒸馏过程中会产生大量有害的废油页岩渣（OSR）。本研究以抚顺市的油页岩残渣和烟煤为原料，在直流电弧炉中生产硅-铝-铁合金，提出了一种高效利用油页岩残渣的新方法。实验总结分析了现有的氧化还原理论，结合实际实验结果，重点研究了氧化还原过程中氧化还原剂的相变。基于气态亚氧化物-碳化物反应理论，提出了球团原料在高温下的还原机理。结果表明，球团原料在还原过程中首先会发生高温分解，生成大量碳化物。碳化物随后与电弧炉高温区产生的金属亚氧化物反应生成合金。所得合金产品的元素分布不均匀，金属 Si 相紧邻 SiC 物质，合金中的 Fe 显著富集了还原的 Al 和 Ti 元素。

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引用次数: 0

Enhancing Sustainability in Aluminum Reduction Cells Through Cathode Repair Optimization and Numerical Simulations Study on Current Distribution and Erosion Hole Impact 通过阴极修复优化和数值模拟提高铝还原电池的可持续性对电流分布和腐蚀孔影响的研究

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-09 DOI: 10.1007/s40831-024-00803-8

Sen Zhou, Mouhamadou A. Diop, Bingliang Gao, Zhaowen Wang, Xianwei Hu, Youjian Yang, Wenju Tao

The present study investigates the impact of erosion holes and subsequent repairs on the current distribution at the cathode-metal interface in aluminum reduction cells. The research focuses on examining the effects of erosion hole location, size, repair material properties, and the modification of cathode collector bars to optimize cathode repair strategies. The findings indicate that erosion holes lead to a localized concentration of current distribution in the metal at the erosion site. Notably, the maximum current density observed reaches 46125 A/m², and the maximum horizontal current in the lateral cell direction at the cathode-metal interface increases with the depth of the erosion hole. Furthermore, the study reveals that the electrical conductivity of repair materials significantly influences current distribution. Materials with high resistivity behave similarly to insulators. Post-repair actions, including the cutting off of the collector bar, result in a noticeable reduction in current density, with a maximum horizontal current of 5860 A/m². These results provide valuable insights into optimizing cathode repair processes, offering implications for enhancing aluminum reduction cells' efficiency, productivity, and cost-effectiveness.

Graphical Abstract

本研究调查了侵蚀孔和后续修复对铝还原电池阴极-金属界面电流分布的影响。研究重点是考察侵蚀孔的位置、大小、修复材料的特性以及阴极集电棒的改性对优化阴极修复策略的影响。研究结果表明，侵蚀孔会导致侵蚀部位金属中的电流分布局部集中。值得注意的是，观察到的最大电流密度达到 46125 A/m2 ，阴极-金属界面横向的最大水平电流随着侵蚀孔深度的增加而增加。此外，研究还发现，修复材料的导电性对电流分布有很大影响。高电阻率材料的行为类似于绝缘体。修复后的操作，包括切断集电棒，导致电流密度明显降低，最大水平电流为 5860 A/m2 。这些结果为优化阴极修复过程提供了宝贵的见解，对提高铝还原电池的效率、生产率和成本效益具有重要意义。

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引用次数: 0

Effects of Na2O and CaCl2 on the Crystallization and Mechanical Properties of CaO-MgO-Al2O3-SiO2 Glass–Ceramics Na2O 和 CaCl2 对 CaO-MgO-Al2O3-SiO2 玻璃陶瓷的结晶和机械特性的影响

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-08 DOI: 10.1007/s40831-024-00819-0

Hong-Yang Wang, Yu Li, Shu-Qiang Jiao, Guo-Hua Zhang

In this paper, we respectively added 5 wt% of Na₂O and CaCl₂ to the CaO–MgO–Al₂O₃–SiO₂ base glass, aiming to analyze the effect of the types of flux, CaCl₂, and traditional flux Na₂O, on the crystallization behavior and mechanical properties of the sintered glass–ceramics. Besides, 1 wt% of Cr₂O₃ was added as the nucleating agent to form the Cr-spinel nucleus and promote the bulk crystallization. The CaCl₂-bearing glass–ceramics (GC-Cl) showed lower porosity and crystallinity compared with the Na₂O-bearing glass–ceramics (GC-Na). After sintering at 950 °C for 1 h, the bending strength, Vickers hardness, and fracture toughness of GC-Cl were 163 MPa, 6.9 GPa, and 2.4 MPa·m^1/2, respectively, while they are 191 MPa, 8.2 GPa, and 2.3 MPa·m^1/2 for the GC-Na. Although the bending strength and hardness of GC-Cl are lower than that of GC-Na, adding CaCl₂ as a flux may provide a route for the comprehensive utilization of CaCl₂-bearing wastes.

Graphical Abstract

本文在 CaO-MgO-Al2O3-SiO2 基底玻璃中分别添加了 5 wt% 的 Na2O 和 CaCl2，旨在分析 CaCl2 和传统助熔剂 Na2O 两种助熔剂对烧结玻璃陶瓷结晶行为和机械性能的影响。此外，还添加了 1 wt% 的 Cr2O3 作为成核剂，以形成铬尖晶核并促进块状结晶。与含 Na2O 的玻璃陶瓷（GC-Na）相比，含 CaCl2 的玻璃陶瓷（GC-Cl）显示出较低的孔隙率和结晶度。在 950 °C 下烧结 1 小时后，GC-Cl 的弯曲强度、维氏硬度和断裂韧性分别为 163 MPa、6.9 GPa 和 2.4 MPa-m1/2，而 GC-Na 的弯曲强度、维氏硬度和断裂韧性分别为 191 MPa、8.2 GPa 和 2.3 MPa-m1/2。虽然 GC-Cl 的抗弯强度和硬度低于 GC-Na，但添加 CaCl2 作为助熔剂可为含 CaCl2 废料的综合利用提供一条途径。图表摘要

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引用次数: 0

Conversion of Lithium Chloride into Lithium Hydroxide Using a Two-Step Solvent Extraction Process in an Agitated Kühni Column 在搅拌库尼柱中采用两步溶剂萃取工艺将氯化锂转化为氢氧化锂

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-08 DOI: 10.1007/s40831-024-00815-4

Nand Peeters, Sofía Riaño, Koen Binnemans

A significant consequence of the green transition is the growing demand of lithium-ion batteries (LIBs), as they are essential for electrical vehicles. In turn, the demand for the raw materials that are needed to produce LIBs is increasing. A common LIB cathode type for electrical cars is lithium nickel manganese cobalt oxide (NMC). Since cobalt is currently considered as a critical raw material, nickel-rich NMC cathodes are now designed with lower cobalt contents. The synthesis of these new NMC types requires LiOH instead of Li₂CO₃, which was used for Co-richer NMC materials in the past. Most production routes of LiOH start from Li₂CO₃ or Li₂SO₄. However, LiCl could also be a potential precursor for LiOH, as it could be obtained from various lithium sources. A two-step solvent extraction process (SX) was developed for direct conversion of LiCl into LiOH, using a phenol (butylhydroxytoluene or BHT) and a mixture of quaternary ammonium chlorides (Aliquat 336) in an aliphatic diluent (Shellsol D70) as the solvent. The SX process was validated in counter-current mode using a rotary agitated Kühni extraction column. The use of a column instead of mixer-settlers reduced the CO₂ uptake by the final product (LiOH), which prevented the partial conversion of LiOH to Li₂CO₃. A total of 75 L of LiCl feed solution was processed in the Kühni column to obtain a solution of LiOH with a final purity of more than 99.95%, at a yield of 96%.

Graphical Abstract

绿色转型的一个重要结果是对锂离子电池（LIB）的需求不断增长，因为锂离子电池对电动汽车至关重要。反过来，对生产锂离子电池所需的原材料的需求也在增加。电动汽车常用的锂离子电池正极类型是锂镍锰钴氧化物（NMC）。由于钴目前被认为是一种关键的原材料，富含镍的 NMC 正极现在被设计成钴含量较低的类型。这些新型 NMC 的合成需要 LiOH，而不是过去用于 Co-richer NMC 材料的 Li2CO3。大多数 LiOH 的生产路线都是从 Li2CO3 或 Li2SO4 开始。然而，LiCl 也可能是 LiOH 的潜在前体，因为它可以从各种锂源中获得。为了将 LiCl 直接转化为 LiOH，我们开发了一种两步溶剂萃取工艺（SX），使用苯酚（丁基羟基甲苯或 BHT）和脂肪族稀释剂（Shellsol D70）中的季铵氯化物混合物（Aliquat 336）作为溶剂。在逆流模式下，使用旋转搅拌的 Kühni 萃取柱对 SX 工艺进行了验证。使用萃取柱而不是混合沉淀器减少了最终产品（LiOH）对二氧化碳的吸收，从而防止了 LiOH 部分转化为 Li2CO3。Kühni 萃取柱总共处理了 75 升氯化锂进料溶液，得到了最终纯度超过 99.95% 的 LiOH 溶液，收率为 96%。

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引用次数: 0

Extraction of Yttrium from Light-Emitting Diode Waste by Alkali Fusion Followed by Acid Leaching 先碱熔再酸浸从发光二极管废料中提取钇

IF 2.4 3区材料科学 Q3 GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY

Journal of Sustainable Metallurgy

Pub Date : 2024-04-08 DOI: 10.1007/s40831-024-00814-5

Rafael Piumatti de Oliveira, Jonathan Tenório Vinhal, Luciana Harue Yamane, Marcela dos Passos Galluzzi Baltazar, Denise Crocce Romano Espinosa

Literature regarding metals recovery from LED waste mainly focuses on semiconductor materials and precious metals, lacking data about rare earth elements. This paper explores this gap presenting an experimental study of yttrium extraction from LED waste by alkali fusion/acid leaching method. For this purpose, LED samples were obtained from tubular lamp. Chemical and thermal analyses were performed. Alkali fusion preprocessing was adopted followed by nitric acid leaching to solve difficult yttrium extraction from aluminate structure of LED phosphor. A chemical reaction mechanism in the alkali fusion involving degradation of the silicone polymer and destruction of the aluminate phosphor has been proposed as a novel approach to the subsequent easy leaching of rare earths from LED waste. Fusion conditions were 700 °C, for 3 h, NaOH/LED relation 1:1. Leaching solutions and solid residue were analyzed by energy dispersive X-ray fluorescence spectrometry, induced coupled plasma optical emission spectrometry, X-ray diffractometry and Fourier transform infrared spectroscopy. It was observed the undesirable formation of silica gel in the leaching liquor processed in temperatures below 70 °C. In that way, it is recommended the leaching at 90 °C, with formation of insoluble SiO₂. Optimal leaching conditions found were leaching time of 20 min, 1/20 solid/liquid ratio, with 91% yttrium extraction in HNO₃ 2.5 mol/L at 90 °C.

Graphical Abstract

有关从 LED 废料中回收金属的文献主要集中在半导体材料和贵金属方面，缺乏有关稀土元素的数据。本文针对这一空白，介绍了通过碱熔/酸浸法从 LED 废料中提取钇的实验研究。为此，我们从管状灯中提取了 LED 样品。进行了化学和热分析。采用碱熔融预处理后硝酸浸出的方法，解决了从 LED 荧光粉的铝酸盐结构中提取钇的难题。提出了碱熔合过程中硅聚合物降解和铝酸盐荧光粉破坏的化学反应机制，作为随后从 LED 废料中轻松浸出稀土的新方法。熔解条件为 700 °C，持续 3 小时，NaOH/LED 比例为 1:1。通过能量色散 X 射线荧光光谱法、诱导耦合等离子体光发射光谱法、X 射线衍射法和傅立叶变换红外光谱法对浸出液和固体残留物进行了分析。结果表明，在低于 70 °C 的温度下处理的浸出液中会形成不理想的硅胶。因此，建议在 90 °C 下进行沥滤，以形成不溶性的二氧化硅。最佳浸出条件是浸出时间为 20 分钟，固液比为 1/20，在 2.5 摩尔/升的 HNO3 溶液中，钇的萃取率为 91%。

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