Pub Date : 2024-11-06DOI: 10.1016/j.hydromet.2024.106419
Shufen Liu, Shichang Song, Kai Tang, Longgang Ye
The mechanical processing of cemented carbide often generates a considerable amount of grinding waste from cemented carbide (GWCC), which serves as an important secondary resource for recovering Co and W. However, efficient separation of tungsten carbide (WC) and Co from GWCC remains challenging. This study tested an efficient process for separating Co from GWCC using a mixed solution of H2SO4-Na2S2O8. Under optimum conditions of 20 g/L H2SO4, 30 g/L Na2S2O8, 60 °C, and 1 h, the leaching efficiency of Co reached 97.0 %, compared to only 58.6 % when using H2SO4 alone. The kinetics of Co leaching in H2SO4 and H2SO4-Na2S2O8 solutions were determined to be a combination of chemical reaction control and diffusion control, suggesting that Co leaching rate in H2SO4 solution is significantly enhanced by introducing Na2S2O8. Finally, complete recovery of Co was achieved, and pure Co powder with a flower-cluster morphology was prepared from the leaching solution through oxalic acid precipitation followed by vacuum pyrolysis. The regenerative WC and Co powder can be recycled for cemented carbide production.
硬质合金的机械加工通常会产生大量的硬质合金研磨废料（GWCC），这些废料是回收钴和钨的重要二次资源。本研究测试了一种使用 H2SO4-Na2S2O8 混合溶液从 GWCC 中分离出 Co 的高效工艺。在 20 g/L H2SO4、30 g/L Na2S2O8、60 °C 和 1 小时的最佳条件下，钴的浸出效率达到 97.0%，而单独使用 H2SO4 时仅为 58.6%。H2SO4 和 H2SO4-Na2S2O8 溶液中的钴浸出动力学被确定为化学反应控制和扩散控制的结合，表明引入 Na2S2O8 后，H2SO4 溶液中的钴浸出率显著提高。最后，通过草酸沉淀和真空热解，实现了钴的完全回收，并从浸出液中制备出具有花簇形态的纯钴粉。再生 WC 和 Co 粉可循环用于硬质合金生产。
{"title":"Efficient separation and recovery of cobalt from grinding waste of cemented carbide using a sulfuric acid-sodium persulfate mixed solution","authors":"Shufen Liu, Shichang Song, Kai Tang, Longgang Ye","doi":"10.1016/j.hydromet.2024.106419","DOIUrl":"10.1016/j.hydromet.2024.106419","url":null,"abstract":"<div><div>The mechanical processing of cemented carbide often generates a considerable amount of grinding waste from cemented carbide (GWCC), which serves as an important secondary resource for recovering Co and W. However, efficient separation of tungsten carbide (WC) and Co from GWCC remains challenging. This study tested an efficient process for separating Co from GWCC using a mixed solution of H<sub>2</sub>SO<sub>4</sub>-Na<sub>2</sub>S<sub>2</sub>O<sub>8</sub>. Under optimum conditions of 20 g/L H<sub>2</sub>SO<sub>4</sub>, 30 g/L Na<sub>2</sub>S<sub>2</sub>O<sub>8</sub>, 60 °C, and 1 h, the leaching efficiency of Co reached 97.0 %, compared to only 58.6 % when using H<sub>2</sub>SO<sub>4</sub> alone. The kinetics of Co leaching in H<sub>2</sub>SO<sub>4</sub> and H<sub>2</sub>SO<sub>4</sub>-Na<sub>2</sub>S<sub>2</sub>O<sub>8</sub> solutions were determined to be a combination of chemical reaction control and diffusion control, suggesting that Co leaching rate in H<sub>2</sub>SO<sub>4</sub> solution is significantly enhanced by introducing Na<sub>2</sub>S<sub>2</sub>O<sub>8</sub>. Finally, complete recovery of Co was achieved, and pure Co powder with a flower-cluster morphology was prepared from the leaching solution through oxalic acid precipitation followed by vacuum pyrolysis. The regenerative WC and Co powder can be recycled for cemented carbide production.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106419"},"PeriodicalIF":4.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.hydromet.2024.106418
Zhouyi Chai , Minglu Rao , Bin Wen , Li Huang , Haopeng Zhang , Yanfei Xiao
The acid-soluble residue from end-of-life NdFeB magnet waste is often introduced into the ferrous metallurgical process to recover iron oxide as a value added product, but this approach has a low economic value. In this work, a ferrous chloride solution from NdFeB magnet waste containing rare earth elements, which was obtained after the leaching and impurity removal process from the acid-soluble residue, was used as the raw material. The crystallization mechanism and reaction kinetics in the oxidation precipitation process were studied to prepare high-purity iron oxide. The results showed that the growth of γ-FeOOH flakes with smooth surfaces and uniform morphologies could be explained by Ostwald's ripening theory. The apparent activation energy of the oxidative precipitation reaction of ferrous iron was 56.8 kJ/mol, indicating a chemically controlled reactions. Under the optimal oxidative precipitation conditions, the precipitation efficiency of ferrous ions and rare earth elements was 98.8 % and < 1 %, respectively. The precipitated product was well-crystallized γ-FeOOH with an aggregated flake morphology. It was roasted at 700 °C for 2 h to obtain an iron oxide product with a purity of 99.6 %. This study could provide technical support for the valuable utilization of acid-soluble residues from NdFeB magnet waste and to propose new methods for the utilization of other iron wastes and residues.
{"title":"Preparation of high-purity iron oxide from end-of-life NdFeB magnet waste","authors":"Zhouyi Chai , Minglu Rao , Bin Wen , Li Huang , Haopeng Zhang , Yanfei Xiao","doi":"10.1016/j.hydromet.2024.106418","DOIUrl":"10.1016/j.hydromet.2024.106418","url":null,"abstract":"<div><div>The acid-soluble residue from end-of-life NdFeB magnet waste is often introduced into the ferrous metallurgical process to recover iron oxide as a value added product, but this approach has a low economic value. In this work, a ferrous chloride solution from NdFeB magnet waste containing rare earth elements, which was obtained after the leaching and impurity removal process from the acid-soluble residue, was used as the raw material. The crystallization mechanism and reaction kinetics in the oxidation precipitation process were studied to prepare high-purity iron oxide. The results showed that the growth of γ-FeOOH flakes with smooth surfaces and uniform morphologies could be explained by Ostwald's ripening theory. The apparent activation energy of the oxidative precipitation reaction of ferrous iron was 56.8 kJ/mol, indicating a chemically controlled reactions. Under the optimal oxidative precipitation conditions, the precipitation efficiency of ferrous ions and rare earth elements was 98.8 % and < 1 %, respectively. The precipitated product was well-crystallized γ-FeOOH with an aggregated flake morphology. It was roasted at 700 °C for 2 h to obtain an iron oxide product with a purity of 99.6 %. This study could provide technical support for the valuable utilization of acid-soluble residues from NdFeB magnet waste and to propose new methods for the utilization of other iron wastes and residues.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106418"},"PeriodicalIF":4.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-03DOI: 10.1016/j.hydromet.2024.106417
Georgiana Moldoveanu, Vladimiros Papangelakis
Cerium removal from solution via oxidative precipitation with hydrogen peroxide was investigated in a batch reactor to identify optimum conditions for maximum Ce removal. Tests were performed under ambient temperature at pH 2, 3, 4 and 5, using the exact stoichiometric requirement and 30 % and 50 % excess, respectively. It was found that, unlike the usual direct Ce(OH)4 formation presented in the literature for most oxidants, the reaction with hydrogen peroxide proceeded via a metastable ceric hydroxide, with conversion rates increased by increasing temperature. Standard free energies of reaction were calculated for both routes. To better understand the process, the oxidation of Ce(III) to Ce(IV) and the precipitation of Ce(OH)4 were studied separately via a decoupled approach at low pH and reaction mechanisms for each process were proposed. The Ce(III) oxidation reaction was identified as the rate-limiting step, whereas Ce(IV) precipitation was fast and quantitative. In the pH range of 3–5, Ce removal extents varied between 80 and 95 %, depending on the hydrogen peroxide excess. Following the Ce removal step via oxidative precipitation, it was found that a 2 h ageing stage at 80 °C and pH 2.5 was required to complete the transition of cerium hydroxy-peroxide to the more stable ceric hydroxide and decompose any residual H2O2.
{"title":"Separation of cerium from solution by oxidative precipitation with hydrogen peroxide: The reaction mechanism","authors":"Georgiana Moldoveanu, Vladimiros Papangelakis","doi":"10.1016/j.hydromet.2024.106417","DOIUrl":"10.1016/j.hydromet.2024.106417","url":null,"abstract":"<div><div>Cerium removal from solution via oxidative precipitation with hydrogen peroxide was investigated in a batch reactor to identify optimum conditions for maximum Ce removal. Tests were performed under ambient temperature at pH 2, 3, 4 and 5, using the exact stoichiometric requirement and 30 % and 50 % excess, respectively. It was found that, unlike the usual direct Ce(OH)<sub>4</sub> formation presented in the literature for most oxidants, the reaction with hydrogen peroxide proceeded via a metastable ceric hydroxide, with conversion rates increased by increasing temperature. Standard free energies of reaction were calculated for both routes. To better understand the process, the oxidation of Ce(III) to Ce(IV) and the precipitation of Ce(OH)<sub>4</sub> were studied separately via a decoupled approach at low pH and reaction mechanisms for each process were proposed. The Ce(III) oxidation reaction was identified as the rate-limiting step, whereas Ce(IV) precipitation was fast and quantitative. In the pH range of 3–5, Ce removal extents varied between 80 and 95 %, depending on the hydrogen peroxide excess. Following the Ce removal step via oxidative precipitation, it was found that a 2 h ageing stage at 80 °C and pH 2.5 was required to complete the transition of cerium hydroxy-peroxide to the more stable ceric hydroxide and decompose any residual H<sub>2</sub>O<sub>2</sub>.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106417"},"PeriodicalIF":4.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Germanium plays an essential role in many high-tech fields because of its excellent electrical and optical properties. As a zinc refining by-product, zinc oxide dust (ZOD) is one of the most important sources of germanium recovery. However, the low leaching efficiency of germanium seriously hinders germanium recovery. This study focuses on the phase evolution and elemental distribution of zinc and germanium during the zinc refining process by analyzing the occurrence state of zinc and germanium in products and the key factors and chemical reactions causing the loss of zinc and germanium during the process. In the sulfuric-acid leaching process without an oxidant, the sulfides encapsulating germanium cannot be leached, which resulted in a loss of germanium. In addition, the formation of an insoluble PbSO4 coating layer and silica compounds during the sulfuric-acid leaching impeded the leaching reactions. Accordingly, pre-treatment by oxidative leaching with Fe3+ and the role of NaAc in dissolving PbSO4 were tested. The efficiency of Ge recovery is approximately 30 % higher than that of the conventional leaching process.
{"title":"Phase evolution and elemental distribution of zinc and germanium during the sulfide roasting, zinc fuming and leaching processes: Benefit of pretreating zinc oxide dust","authors":"Yundong Zhu , Xilin Geng , Jiankang Wen , Wei Qu , Liangshi Wang","doi":"10.1016/j.hydromet.2024.106416","DOIUrl":"10.1016/j.hydromet.2024.106416","url":null,"abstract":"<div><div>Germanium plays an essential role in many high-tech fields because of its excellent electrical and optical properties. As a zinc refining by-product, zinc oxide dust (ZOD) is one of the most important sources of germanium recovery. However, the low leaching efficiency of germanium seriously hinders germanium recovery. This study focuses on the phase evolution and elemental distribution of zinc and germanium during the zinc refining process by analyzing the occurrence state of zinc and germanium in products and the key factors and chemical reactions causing the loss of zinc and germanium during the process. In the sulfuric-acid leaching process without an oxidant, the sulfides encapsulating germanium cannot be leached, which resulted in a loss of germanium. In addition, the formation of an insoluble PbSO<sub>4</sub> coating layer and silica compounds during the sulfuric-acid leaching impeded the leaching reactions. Accordingly, pre-treatment by oxidative leaching with Fe<sup>3+</sup> and the role of NaAc in dissolving PbSO<sub>4</sub> were tested. The efficiency of Ge recovery is approximately 30 % higher than that of the conventional leaching process.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106416"},"PeriodicalIF":4.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.hydromet.2024.106414
Gisele Azimi
The growing demand for rare earth elements, pivotal for modern technologies, has necessitated the development of efficient and sustainable extraction methods from ionic clays. This review provides a comprehensive analysis of the advancements in rare earth recovery from ionic clays, focusing on the geological, geochemical, and technological aspects of the extraction processes. Historically, traditional methods of extracting rare earths from mineral ores have been environmentally detrimental and economically intensive due to their complex multi-step procedures and the handling of radioactive materials. In contrast, ionic clays, primarily found in weathered crusts of granite and volcanic rocks, offer a more accessible source of rare earths, particularly heavy rare earth elements (HREEs), through simpler ion exchange processes. The necessity to discuss this topic arises from the increasing environmental and economic pressures to find greener and more sustainable methods of rare earth extraction. The review highlights the transition towards environmentally friendly leaching agents, such as non-ammonium salts, and the integration of advanced techniques like microbial adsorption and solvent extraction. These innovations aim to enhance extraction efficiency while reducing ecological footprints. Additionally, the review highlights the importance of understanding the geological conditions that favor the formation of ionic rare earth deposits, such as climate, topography, and geological history, which are critical for efficient prospecting and exploitation. Moreover, the paper presents a life cycle analysis of in-situ leaching of rare earths from ionic clays, a method that minimizes surface disruption and environmental impact compared with conventional mining. The efficacy of this method is evaluated through case studies and field implementations, demonstrating significant improvements in efficiencies of recovery and operational sustainability. In conclusion, this review emphasizes the strategic importance of rare earth extraction from ionic clays, not only to meet the rising global demand but also to support the advancement of green technologies essential for a sustainable future. It calls for continued research into alternative extraction technologies and methods that balance economic feasibility with environmental responsibility, ensuring the sustainable exploitation of these critical resources.
{"title":"Technological advancements in rare earth elements recovery from ionic clays: A comprehensive review","authors":"Gisele Azimi","doi":"10.1016/j.hydromet.2024.106414","DOIUrl":"10.1016/j.hydromet.2024.106414","url":null,"abstract":"<div><div>The growing demand for rare earth elements, pivotal for modern technologies, has necessitated the development of efficient and sustainable extraction methods from ionic clays. This review provides a comprehensive analysis of the advancements in rare earth recovery from ionic clays, focusing on the geological, geochemical, and technological aspects of the extraction processes. Historically, traditional methods of extracting rare earths from mineral ores have been environmentally detrimental and economically intensive due to their complex multi-step procedures and the handling of radioactive materials. In contrast, ionic clays, primarily found in weathered crusts of granite and volcanic rocks, offer a more accessible source of rare earths, particularly heavy rare earth elements (HREEs), through simpler ion exchange processes. The necessity to discuss this topic arises from the increasing environmental and economic pressures to find greener and more sustainable methods of rare earth extraction. The review highlights the transition towards environmentally friendly leaching agents, such as non-ammonium salts, and the integration of advanced techniques like microbial adsorption and solvent extraction. These innovations aim to enhance extraction efficiency while reducing ecological footprints. Additionally, the review highlights the importance of understanding the geological conditions that favor the formation of ionic rare earth deposits, such as climate, topography, and geological history, which are critical for efficient prospecting and exploitation. Moreover, the paper presents a life cycle analysis of <em>in-situ</em> leaching of rare earths from ionic clays, a method that minimizes surface disruption and environmental impact compared with conventional mining. The efficacy of this method is evaluated through case studies and field implementations, demonstrating significant improvements in efficiencies of recovery and operational sustainability. In conclusion, this review emphasizes the strategic importance of rare earth extraction from ionic clays, not only to meet the rising global demand but also to support the advancement of green technologies essential for a sustainable future. It calls for continued research into alternative extraction technologies and methods that balance economic feasibility with environmental responsibility, ensuring the sustainable exploitation of these critical resources.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106414"},"PeriodicalIF":4.8,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A separation method for the recovery of neodymium(III) from two different media, chloride and nitrate, by implementing solvent extraction technique with a novel lipophilic diamide derivative of ethylenediamine tetraacetic acid (EDTA), namely 2,2’-N,N′-didecyl-dioxo-N,N′,N″,N″’-tetraazatetratriacontane-N″,N″’-diyl diacetic acid (H2E-4C10), has been investigated. Initial screening results demonstrated acceptable solubility (ca. 15 mM) of the diamide in 1,3-diisopropylbenzene (DiPB) and in a 93:7 v:v n-dodecane:n-octanol mixture (DOm) as non-polar diluents. Further investigations aiming at determining operational parameters associated with the befitted extractant systems were conducted at pH ranging from 2 to 4 in chloride and nitrate media. A pH-dependent performance of the proposed systems revealed loading capacity peaking at pH = 3 with the respective values of 1.7 and 2.0 g L−1 in nitrate and chloride media. The extraction efficiency, the distribution coefficients, and the separation factor (E%,D and SF, respectively) were determined for an equimolar mixture of neodymium (Nd) and two other potential competitive lanthanides, namely dysprosium (Dy) and praseodymium (Pr). The best selectivity was observed in the chloride medium at pH = 4 yielding SFNd/Pr = 1.48 and SFNd/Dy = 2.03. Neodymium-to-extractant stoichiometry was evidenced in chloroform to be 1:1 H2E:Nd at pH = 2. Thermodynamic constants related to the considered extraction equilibrium have been determined by using the Van't Hoff relation and the slope analysis method. It appeared within the selected pH-range that the mechanism of the Nd3+ transfer was strongly influenced by the nature of the diluent. This was illustrated by the enthalpy-driven transfer when Nd3+ was extracted with the H2E-4C10-Dom system (aliphatic diluent) while the transfer became entropy-driven when the extraction was performed with the H2E-4C10-DiPB system (aromatic diluent). The complexation of Nd3+ involved mainly the participation of both the amide and carboxylic functional groups. The transfer of the cation to the organic phase might occur through the formation of the Nd(HE)A2 complex (where A is either a nitrate or a chloride anion), allowing for the lowest associated standard Gibbs free energy of transfer (−28 < ΔG° < −24 kJ mol−1) regardless of the aqueous feed.
{"title":"Lipophilic EDTA-based ligands in different diluents for the extraction of rare earths: Preliminary results with Nd(III), Dy(III) and Pr(III) in chloride and nitrate media","authors":"Tamir Sukhbaatar , Raphaëlle Piton , Fabrice Giusti , Guilhem Arrachart , Magali Duvail , Aarti Kumari , Santosh Daware , Shally Gupta , Sriram Goverapet , Sushanta Kumar Sahu , Beena Rai , Stéphane Pellet-Rostaing","doi":"10.1016/j.hydromet.2024.106415","DOIUrl":"10.1016/j.hydromet.2024.106415","url":null,"abstract":"<div><div>A separation method for the recovery of neodymium(III) from two different media, chloride and nitrate, by implementing solvent extraction technique with a novel lipophilic diamide derivative of ethylenediamine tetraacetic acid (EDTA), namely 2,2’-<em>N</em>,<em>N</em>′-didecyl-dioxo-<em>N</em>,<em>N′</em>,<em>N″</em>,<em>N″’</em>-tetraazatetratriacontane-<em>N″</em>,<em>N″’</em>-diyl diacetic acid (<strong>H</strong><sub><strong>2</strong></sub><strong>E-4C</strong><sub><strong>10</strong></sub>), has been investigated. Initial screening results demonstrated acceptable solubility (ca. 15 mM) of the diamide in 1,3-diisopropylbenzene (DiPB) and in a 93:7 v:v <em>n</em>-dodecane:<em>n</em>-octanol mixture (DOm) as non-polar diluents. Further investigations aiming at determining operational parameters associated with the befitted extractant systems were conducted at pH ranging from 2 to 4 in chloride and nitrate media. A pH-dependent performance of the proposed systems revealed loading capacity peaking at pH = 3 with the respective values of 1.7 and 2.0 g L<sup>−1</sup> in nitrate and chloride media. The extraction efficiency, the distribution coefficients, and the separation factor (<em>E</em><sub>%,</sub> <em>D</em> and <em>SF</em>, respectively) were determined for an equimolar mixture of neodymium (Nd) and two other potential competitive lanthanides, namely dysprosium (Dy) and praseodymium (Pr). The best selectivity was observed in the chloride medium at pH = 4 yielding <em>SF</em><sub>Nd/Pr</sub> = 1.48 and <em>SF</em><sub>Nd/Dy</sub> = 2.03. Neodymium-to-extractant stoichiometry was evidenced in chloroform to be 1:1 H<sub>2</sub>E:Nd at pH = 2. Thermodynamic constants related to the considered extraction equilibrium have been determined by using the Van't Hoff relation and the slope analysis method. It appeared within the selected pH-range that the mechanism of the Nd<sup>3+</sup> transfer was strongly influenced by the nature of the diluent. This was illustrated by the enthalpy-driven transfer when Nd<sup>3+</sup> was extracted with the <strong>H</strong><sub><strong>2</strong></sub><strong>E-4C</strong><sub><strong>10</strong></sub>-Dom system (aliphatic diluent) while the transfer became entropy-driven when the extraction was performed with the <strong>H</strong><sub><strong>2</strong></sub><strong>E-4C</strong><sub><strong>10</strong></sub>-DiPB system (aromatic diluent). The complexation of Nd<sup>3+</sup> involved mainly the participation of both the amide and carboxylic functional groups. The transfer of the cation to the organic phase might occur through the formation of the Nd(<em>HE</em>)<em>A</em><sub>2</sub> complex (where <em>A</em> is either a nitrate or a chloride anion), allowing for the lowest associated standard Gibbs free energy of transfer (−28 < <em>ΔG</em>° < −24 kJ mol<sup>−1</sup>) regardless of the aqueous feed.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106415"},"PeriodicalIF":4.8,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.hydromet.2024.106412
Chunhua Wang , Runhan Yan , Hongmin Cui , Jinsong Shi , Nanfu Yan , Shengyong You
The separation of yttrium (Y) from heavy rare-earth elements (HREEs) is a major issue for ion-adsorbed rare-earth deposits. This study describes a new extraction system to develop efficient separation of Y from HREEs in a chloride medium using diglycolamic acid as the extractant. The extraction performance of N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA) for mixed REEs of an ion-adsorbed rare-earth deposit was investigated. The extraction order of the REEs in the HDEHDGA system followed a positive sequence, and the extraction behavior of Y resembled that of the middle REEs. Compared with naphthenic acid (NA) and sec-octylphenoxy acetic acid (CA12), HDEHDGA exhibited better separation performance for HREEs (Ho-Lu) and Y. The separation factors of Ho/Y, Er/Y, Tm/Y, Yb/Y, and Lu/Y in the Y-enriched solution were 4.41, 4.29, 3.77, 3.26, and 3.11, respectively. Combined slope analysis and electrospray ionization–high-resolution mass spectroscopy (ESI-HRMS) results identified cation exchange as the extraction mechanism of RE3+. Furthermore, the molecular dynamics simulation results provided new insights into the dynamic behaviors of Y3+ and Yb3+ extraction and revealed that the interaction of HDEHDGA with Yb3+ was stronger than that with Y3+. In addition, the loading capacity and recyclability of HDEHDGA were evaluated. This study highlights the potential of the HDEHDGA system for the separation of Y from HREEs.
{"title":"Separation of yttrium from ion-adsorbed-rare-earth deposit leachates using N,N-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA): Preliminary experimental and molecular dynamics simulation studies","authors":"Chunhua Wang , Runhan Yan , Hongmin Cui , Jinsong Shi , Nanfu Yan , Shengyong You","doi":"10.1016/j.hydromet.2024.106412","DOIUrl":"10.1016/j.hydromet.2024.106412","url":null,"abstract":"<div><div>The separation of yttrium (Y) from heavy rare-earth elements (HREEs) is a major issue for ion-adsorbed rare-earth deposits. This study describes a new extraction system to develop efficient separation of Y from HREEs in a chloride medium using diglycolamic acid as the extractant. The extraction performance of <em>N</em>,<em>N</em>-di(2-ethylhexyl)-diglycolamic acid (HDEHDGA) for mixed REEs of an ion-adsorbed rare-earth deposit was investigated. The extraction order of the REEs in the HDEHDGA system followed a positive sequence, and the extraction behavior of Y resembled that of the middle REEs. Compared with naphthenic acid (NA) and sec-octylphenoxy acetic acid (CA12), HDEHDGA exhibited better separation performance for HREEs (Ho-Lu) and Y. The separation factors of Ho/Y, Er/Y, Tm/Y, Yb/Y, and Lu/Y in the Y-enriched solution were 4.41, 4.29, 3.77, 3.26, and 3.11, respectively. Combined slope analysis and electrospray ionization–high-resolution mass spectroscopy (ESI-HRMS) results identified cation exchange as the extraction mechanism of RE<sup>3+</sup>. Furthermore, the molecular dynamics simulation results provided new insights into the dynamic behaviors of Y<sup>3+</sup> and Yb<sup>3+</sup> extraction and revealed that the interaction of HDEHDGA with Yb<sup>3+</sup> was stronger than that with Y<sup>3+</sup>. In addition, the loading capacity and recyclability of HDEHDGA were evaluated. This study highlights the potential of the HDEHDGA system for the separation of Y from HREEs.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106412"},"PeriodicalIF":4.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.hydromet.2024.106413
Aleksei Kritskii , Gerardo Fuentes , Haci Deveci
Hydrothermal pretreatment of copper concentrates in acidified copper sulfate solution has been known since the beginning of the last century as an approach to the chemical enrichment of copper concentrates. While the pilot-scale demonstration of this approach exists, detailed investigations into the underlying chemical interactions that form the basis of this technology are rarely available in open sources. This review attempts to summarize research data on the hydrothermal treatment of sulfide minerals for over a century. It focuses on the hydrothermal interactions between acidified copper sulfate solution and sulfide minerals, which are of key significance for the hydrothermal enrichment process, including the main copper minerals (CuFeS2, Cu5FeS4, CuS, Cu2S) and those (e.g., ZnS, FeS2, and PbS) that are often associated with copper concentrates as penalty impurities. Studies on the hydrothermal enrichment of various sulfide raw materials (including copper concentrates) have shown that parameters such as temperature, the concentration of reagents, and the molar ratio of Cu in solution to Cu in solid, among others, influence the efficiency of the process.
Furthermore, reaction kinetics seem to assume prime importance in controlling the hydrothermal treatment process. High activation energies, fractional orders of the reactions with respect to the reagents, and diffusion-controlled kinetics characterize the hydrothermal interactions between sulfides and acidified copper sulfate solution. The findings in the literature were critically examined and discussed with the delineation of further research needs.
{"title":"A critical review of hydrothermal treatment of sulfide minerals with Cu(II) solution in H2SO4 media","authors":"Aleksei Kritskii , Gerardo Fuentes , Haci Deveci","doi":"10.1016/j.hydromet.2024.106413","DOIUrl":"10.1016/j.hydromet.2024.106413","url":null,"abstract":"<div><div>Hydrothermal pretreatment of copper concentrates in acidified copper sulfate solution has been known since the beginning of the last century as an approach to the chemical enrichment of copper concentrates. While the pilot-scale demonstration of this approach exists, detailed investigations into the underlying chemical interactions that form the basis of this technology are rarely available in open sources. This review attempts to summarize research data on the hydrothermal treatment of sulfide minerals for over a century. It focuses on the hydrothermal interactions between acidified copper sulfate solution and sulfide minerals, which are of key significance for the hydrothermal enrichment process, including the main copper minerals (CuFeS<sub>2</sub>, Cu<sub>5</sub>FeS<sub>4</sub>, CuS, Cu<sub>2</sub>S) and those (e.g., ZnS, FeS<sub>2,</sub> and PbS) that are often associated with copper concentrates as penalty impurities. Studies on the hydrothermal enrichment of various sulfide raw materials (including copper concentrates) have shown that parameters such as temperature, the concentration of reagents, and the molar ratio of Cu in solution to Cu in solid, among others, influence the efficiency of the process.</div><div>Furthermore, reaction kinetics seem to assume prime importance in controlling the hydrothermal treatment process. High activation energies, fractional orders of the reactions with respect to the reagents, and diffusion-controlled kinetics characterize the hydrothermal interactions between sulfides and acidified copper sulfate solution. The findings in the literature were critically examined and discussed with the delineation of further research needs.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106413"},"PeriodicalIF":4.8,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.hydromet.2024.106409
J. Valenzuela-Elgueta , A.V. Delgado , S. Ahualli
Because of the common presence of different silicate minerals, like kaolinite, montmorillonite and muscovite as gangue minerals in the beneficiation of copper oxide ores, the interaction between copper(II) ions in solution and each of these minerals is a field of strong interest, considering their implications on the aggregation of these minerals in the extreme pH conditions typical of hydrometallurgical unit operations for copper production. After copper adsorption isotherms determination at pH 2 and 4, specific adsorption data were fitted to both Langmuir and Freundlich models. It was found that adsorption is systematically larger at pH 4, and that montmorillonite is the mineral that displays a larger adsorption capacity, as in principle expected by its larger cation exchange capacity, CEC. A good fitting to the Langmuir model was obtained for the three samples, and montmorillonite also appears to conform to Freundlich isotherm predictions, as the tested concentrations of copper(II) do not allow to reach saturation. Furthermore, some desorption is measured for kaolinite and muscovite at the highest copper concentrations, probably because of significant interactions between the adsorbed ions. No such desorption was detected in montmorillonite samples. An XPS analysis of the surfaces of the three minerals suggests that copper adsorption in kaolinite is not associated to a cation exchange process but rather to electrostatic interactions between silica-like faces of the clay. In contrast, ionic exchange of structural calcium (for montmorillonite) or potassium (in the case of muscovite) seems to be the predominant mechanism of Cu(II) adsorption in the other two samples. Electrophoretic mobility determinations agree with this hypothesis: the mobility (always negative, with no traces of charge inversion) decreases in absolute value when kaolinite particles are in contact with solutions of increasing copper concentration at pH 2 or pH 4. On the other hand, the electrophoretic mobility values of muscovite and montmorillonite showed a weak pH and copper concentration dependence, a result that matches well with the ion exchange processes detected in the XPS measurements.
{"title":"Fundamentals of copper(II) adsorption on phyllosilicate minerals relevant to crud formation in solvent extraction from heap leach liquors","authors":"J. Valenzuela-Elgueta , A.V. Delgado , S. Ahualli","doi":"10.1016/j.hydromet.2024.106409","DOIUrl":"10.1016/j.hydromet.2024.106409","url":null,"abstract":"<div><div>Because of the common presence of different silicate minerals, like kaolinite, montmorillonite and muscovite as gangue minerals in the beneficiation of copper oxide ores, the interaction between copper(II) ions in solution and each of these minerals is a field of strong interest, considering their implications on the aggregation of these minerals in the extreme pH conditions typical of hydrometallurgical unit operations for copper production. After copper adsorption isotherms determination at pH 2 and 4, specific adsorption data were fitted to both Langmuir and Freundlich models. It was found that adsorption is systematically larger at pH 4, and that montmorillonite is the mineral that displays a larger adsorption capacity, as in principle expected by its larger cation exchange capacity, CEC. A good fitting to the Langmuir model was obtained for the three samples, and montmorillonite also appears to conform to Freundlich isotherm predictions, as the tested concentrations of copper(II) do not allow to reach saturation. Furthermore, some desorption is measured for kaolinite and muscovite at the highest copper concentrations, probably because of significant interactions between the adsorbed ions. No such desorption was detected in montmorillonite samples. An XPS analysis of the surfaces of the three minerals suggests that copper adsorption in kaolinite is not associated to a cation exchange process but rather to electrostatic interactions between silica-like faces of the clay. In contrast, ionic exchange of structural calcium (for montmorillonite) or potassium (in the case of muscovite) seems to be the predominant mechanism of Cu(II) adsorption in the other two samples. Electrophoretic mobility determinations agree with this hypothesis: the mobility (always negative, with no traces of charge inversion) decreases in absolute value when kaolinite particles are in contact with solutions of increasing copper concentration at pH 2 or pH 4. On the other hand, the electrophoretic mobility values of muscovite and montmorillonite showed a weak pH and copper concentration dependence, a result that matches well with the ion exchange processes detected in the XPS measurements.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106409"},"PeriodicalIF":4.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.hydromet.2024.106411
Z.H. Ismail, S.E. Rizk, E.M. Abu Elgoud, H.F. Aly
The ion exchange process using an anion exchange resin (Bio-Rex 5) was employed with batch and column techniques to isolate nuclear-grade zirconium/hafnium from a leach solution of zircon ore. Batch studies were conducted to optimize the conditions for sorption and desorption of Zr(IV) and Hf(IV). The highest separation factor of 10.3 was achieved under equilibrium conditions of 11.0 mol/L HCl, contact time of 30.0 min, solution volume-to-mass of resin ratio of 0.10, and 15 °C. The sorption process for both metals obeyed a pseudo-second-order model and the experimental sorption data was well-described by both Langmuir and Freundlich models. The maximum sorption capacities were determined to be 46.2 mg/g for Zr(IV) and 37.8 mg/g for Hf(IV). The Zr(IV) and Hf(IV) ions were effectively desorbed by 0.1 mol/L nitric and 2.0 mol/L hydrochloric acid solutions, respectively, with total yields of 89.7 % Zr(IV) and 85.8 % Hf(IV) via multistage desorption processes. In both batch and column techniques, the resin exhibited sorption selectivity for Zr and Hf over interfering elements in the hydrochloric acid leach solution of zircon sand. The loaded resin from real leach solution was subjected to desorption, zirconium sulfate precipitation, and calcination at 650 °C, resulting in a pure zirconia powder suitable for nuclear applications. This technique presents a promising effective method for the selective separation and recovery of high-purity zirconium and hafnium from their natural sources.
{"title":"Separation of hafnium from zircon leach solution using anion-exchange resin and production of high-purity zirconia for nuclear applications","authors":"Z.H. Ismail, S.E. Rizk, E.M. Abu Elgoud, H.F. Aly","doi":"10.1016/j.hydromet.2024.106411","DOIUrl":"10.1016/j.hydromet.2024.106411","url":null,"abstract":"<div><div>The ion exchange process using an anion exchange resin (Bio-Rex 5) was employed with batch and column techniques to isolate nuclear-grade zirconium/hafnium from a leach solution of zircon ore. Batch studies were conducted to optimize the conditions for sorption and desorption of Zr(IV) and Hf(IV). The highest separation factor of 10.3 was achieved under equilibrium conditions of 11.0 mol/L HCl, contact time of 30.0 min, solution volume-to-mass of resin ratio of 0.10, and 15 °C. The sorption process for both metals obeyed a pseudo-second-order model and the experimental sorption data was well-described by both Langmuir and Freundlich models. The maximum sorption capacities were determined to be 46.2 mg/g for Zr(IV) and 37.8 mg/g for Hf(IV). The Zr(IV) and Hf(IV) ions were effectively desorbed by 0.1 mol/L nitric and 2.0 mol/L hydrochloric acid solutions, respectively, with total yields of 89.7 % Zr(IV) and 85.8 % Hf(IV) via multistage desorption processes. In both batch and column techniques, the resin exhibited sorption selectivity for Zr and Hf over interfering elements in the hydrochloric acid leach solution of zircon sand. The loaded resin from real leach solution was subjected to desorption, zirconium sulfate precipitation, and calcination at 650 °C, resulting in a pure zirconia powder suitable for nuclear applications. This technique presents a promising effective method for the selective separation and recovery of high-purity zirconium and hafnium from their natural sources.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106411"},"PeriodicalIF":4.8,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号