Hydrometallurgy最新文献

{"title":"Research on the short-process of leaching and semi-extraction method of nickel‑cobalt from mixed hydroxide precipitate (MHP) to prepare battery grade products","authors":"Yukun Shen ,&nbsp;Hongyu Wang ,&nbsp;Liang Zhang ,&nbsp;Liyong Zhou ,&nbsp;Chunping Fu ,&nbsp;Kweon Ho Jin ,&nbsp;Mingkang Fang ,&nbsp;Jiade Wang","doi":"10.1016/j.hydromet.2025.106446","DOIUrl":"10.1016/j.hydromet.2025.106446","url":null,"abstract":"<div><div>Mixed nickel‑cobalt hydroxide precipitate (MHP) obtained via pretreatment and leaching of nickel laterite ore, is a vital source of nickel and cobalt. This work proposes an efficient and economical hydrometallurgical process for recovering Ni and Co from MHP. Initially, an acid leaching process was employed, achieving leaching efficiencies of 99.9 % for Ni and 98.3 % for Co. Notably, the leaching efficiency for Mn was significantly lower at 26.1 %, attributed to partial oxidation of Mn. Subsequently, the purification of the leach liquor resulted in a significant reduction of impurities such as Si, Sc, Fe, and Al to concentrations of 18 mg/L, 1.8 mg/L, 0.8 mg/L, and 0.8 mg/L, respectively. Finally, the subsequent semi-extraction process further minimized impurities, including Co, Mn, Mg, and Ca, to levels below 1 mg/L in the purified solution. Furthermore, the Sc enriched in P204 was stripped by 3 mol/L NaOH, yielding a Sc-enriched solid residue with a grade of 30 %. The results show that the process can extract Ni and Co from MHP, and Ni, Co solution are suitable for the production of lithium batteries.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"233 ","pages":"Article 106446"},"PeriodicalIF":4.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379166","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}

{"title":"Investigation of hydrodynamics behavior in a gas-agitated disc and doughnut column for solvent extraction with application to impurity removal from mixed nickel‑cobalt hydroxide precipitate","authors":"Chi Wang ,&nbsp;Dongbing Xu ,&nbsp;Boren Tan ,&nbsp;Chao Chang ,&nbsp;Chenye Wang ,&nbsp;Yong Wang ,&nbsp;Peng Xing ,&nbsp;Huiquan Li ,&nbsp;Xiahui Gui ,&nbsp;Jianguo Yang","doi":"10.1016/j.hydromet.2025.106438","DOIUrl":"10.1016/j.hydromet.2025.106438","url":null,"abstract":"<div><div>Controlling the dispersed phase droplet size within a reasonable range in the extraction column is crucial for enhancing mass transfer efficiency. Traditional high energy-inputs may result in excessive droplet fragmentation in low interfacial tension systems, posing significant challenges in intensifying the extraction process. This work proposes a novel gas-agitated technology to prevent excessive droplet fragmentation. Three extraction systems, with different physical properties, were selected for the experiment: 4, 30, and 50 % (<em>v</em>/v) TBP/kerosene-Water. Within the range where the dispersed phase and continuous velocities vary from 1.47 × 10⁻³ m/s to 2.51 × 10⁻³ m/s, and the gas velocity ranges from 2.36 × 10⁻³ m/s to 1.18 × 10⁻³ m/s (note the order of these velocities should be clearly distinguished if they represent different phases). The droplet size (<em>d</em>₃₂), dispersed-phase holdup (<em>x</em>_d), and gas holdup (<em>x</em>_g) were investigated in a disc-and-doughnut column (DDC) equipped with a gas-input unit. The aim of this investigation was to understand the influence of gas energy-input on hydrodynamic parameters. The results show that gas-input can expand flooding limitation, and it has the ability to break-up droplets, reducing droplets diameter from 3.6 mm to 1.2 mm approximately, while effectively preventing excessive fragmentation. The value of <em>x</em>_d initially decreases and then increases with the increase in gas velocity. Within the operating gas velocity range, the value of <em>x</em>_g increases from 9.7 % to 22.3 %, but without the effect of two-phase velocity. The modified correlations for droplet diameter, dispersed phase holdup, and gas holdup in the gas-agitated extraction column were proposed with deviations of 11.6 %, 15.9 %, and 4.3 %, respectively. These findings are useful to strengthen the low interfacial tension extraction processes in the future. A preliminary study was conducted to investigate the mass transfer enhancement in a gas-agitated column with a typical low interfacial tension extraction system (P204/kerosene-acidic solution of nickel cobalt complex hydroxide). Under similar conditions, extraction with P204/kerosene shows the improvement of metal extraction efficiency with an increase in gas velocity for agitation. The extraction efficiencies of Mg²⁺ and Mn²⁺ were significantly higher when gas-agitated was employed compared to pulsation. This finding indicates that gas-agitated column with moderate energy input is more suitable for low interfacial tension systems.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"233 ","pages":"Article 106438"},"PeriodicalIF":4.8,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159455","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}

{"title":"The role of hydrogen peroxide in the acid dissolution of indium tin oxide (ITO) in the context of selective indium recovery from secondary sources","authors":"Daísa C.A. Gonçalves ,&nbsp;Daniel Majuste","doi":"10.1016/j.hydromet.2025.106437","DOIUrl":"10.1016/j.hydromet.2025.106437","url":null,"abstract":"<div><div>This paper presents a thermodynamic, kinetic, and mechanistic examination of indium and tin extraction from indium tin oxide (ITO) in acidic sulfate solutions containing hydrogen peroxide (H₂O₂). The experimental approach included a comprehensive characterization of commercial ITO powder and leach residues by different techniques, as well as a systematic investigation of the effects of temperature, sulfuric acid (H₂SO₄) concentration, and hydrogen peroxide concentration on the leaching behavior (yield and rate) of indium and tin. The leaching tests showed that the presence of H₂O₂ in the H₂SO₄ solutions results in a significant increase in the leaching of indium, primarily at moderate temperatures. Furthermore, an increase in the H₂O₂ concentration in the solutions leads to a decrease in the concentration of tin in the leach liquor. The extraction of indium from ITO appears to occur in two steps. The first step involves the spontaneous hydration of In₂O₃ to form indium(III) hydroxide, In(OH)₃, while the second step is the attack of this phase by protons (H⁺) to form soluble In³⁺ species, which is also a spontaneous reaction. The rate-determining step of indium extraction from fine ITO particles (mean particle size = 18 μm) is likely the diffusion of H⁺ through the pores of hydrated In₂O₃ particles and the grains of SnO₂ surrounding these particles. With regard to the extraction of tin, the following sequence of steps was proposed: (i) the spontaneous reduction of the SnO₂ phase in the acid solutions to Sn²⁺ by the active hydroperoxyl (HOO^•) radical, which is formed from the decomposition reaction of H₂O₂; (ii) the spontaneous oxidation of Sn²⁺ ions to Sn⁴⁺ by the oxygen molecules and the active hydroxyl (HO^•) radical, which are also formed from the decomposition reaction of H₂O₂; and (iii) the spontaneous precipitation of SnO₂ from the unstable Sn⁴⁺ ions. A better understanding of the kinetics and mechanism of ITO dissolution in the H₂SO₄-H₂O₂ media may be helpful in the design and improvement of leaching processes targeting high indium recovery by selective leaching.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"233 ","pages":"Article 106437"},"PeriodicalIF":4.8,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159761","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}

{"title":"A novel method for leaching rare earth element from fluorescent lamp waste via acid fusion","authors":"Guilherme Vieira Vaz ,&nbsp;Fernanda Veronesi Marinho Pontes ,&nbsp;Lucas André Bezerra Salgado ,&nbsp;Manuel Castro Carneiro ,&nbsp;Jéssica Frontino Paulino","doi":"10.1016/j.hydromet.2024.106420","DOIUrl":"10.1016/j.hydromet.2024.106420","url":null,"abstract":"<div><div>Spent fluorescent lamps are alternatives to primary sources of rare earth elements. For recycling, the most common hydrometallurgical processes involve leaching with mineral acids, combined or not with alkaline fusion, which must be followed by another acidic leaching step for terbium, cerium, and lanthanum recovery. This study proposes a novel method employing acid fusion with potassium pyrosulfate (K₂S₂O₇) and leaching with water at 25 °C. A full factorial design (2³) was employed to study the following variables for the fusion process: temperature (450–550 °C), flux/sample mass ratio (2.2–3.0), and time (30–120 min). Under the optimal experimental conditions, the maximum recovery for La was 56.0 %. Recoveries were close to or greater than 70 % for Y, Ce, Eu, and Tb, at lower temperatures compared to those used in alkaline fusion, without the need for additional reagents and heating in the REE leaching step after fusion.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106420"},"PeriodicalIF":4.8,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723435","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}

{"title":"Efficient separation and recovery of cobalt from grinding waste of cemented carbide using a sulfuric acid-sodium persulfate mixed solution","authors":"Shufen Liu,&nbsp;Shichang Song,&nbsp;Kai Tang,&nbsp;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 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.</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}

{"title":"Preparation of high-purity iron oxide from end-of-life NdFeB magnet waste","authors":"Zhouyi Chai ,&nbsp;Minglu Rao ,&nbsp;Bin Wen ,&nbsp;Li Huang ,&nbsp;Haopeng Zhang ,&nbsp;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 &lt; 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}

{"title":"Separation of cerium from solution by oxidative precipitation with hydrogen peroxide: The reaction mechanism","authors":"Georgiana Moldoveanu,&nbsp;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)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.</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}

{"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 ,&nbsp;Xilin Geng ,&nbsp;Jiankang Wen ,&nbsp;Wei Qu ,&nbsp;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 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.</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}

{"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}

{"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 ,&nbsp;Raphaëlle Piton ,&nbsp;Fabrice Giusti ,&nbsp;Guilhem Arrachart ,&nbsp;Magali Duvail ,&nbsp;Aarti Kumari ,&nbsp;Santosh Daware ,&nbsp;Shally Gupta ,&nbsp;Sriram Goverapet ,&nbsp;Sushanta Kumar Sahu ,&nbsp;Beena Rai ,&nbsp;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>_{<strong>2</strong>}<strong>E-4C</strong>_{<strong>10</strong>}), 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⁻¹ in nitrate and chloride media. The extraction efficiency, the distribution coefficients, and the separation factor (<em>E</em>_%, <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>_Nd/Pr = 1.48 and <em>SF</em>_Nd/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 <strong>H</strong>_{<strong>2</strong>}<strong>E-4C</strong>_{<strong>10</strong>}-Dom system (aliphatic diluent) while the transfer became entropy-driven when the extraction was performed with the <strong>H</strong>_{<strong>2</strong>}<strong>E-4C</strong>_{<strong>10</strong>}-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(<em>HE</em>)<em>A</em>₂ 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 &lt; <em>ΔG</em>° &lt; −24 kJ mol⁻¹) 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}