Pub Date : 2025-07-29DOI: 10.1016/j.hydromet.2025.106536
Wenjia Kou , Wengang Liu , Wenbao Liu , Wei Zuo , Weichao Li
To improve the utilization of valuable metal components in iron-bearing serpentine tailings, leaching experiments were conducted with microwave pretreatment, and the leaching conditions were optimized. The MgO and total Fe (Fe(II) and Fe(III)) leaching efficiencies reached 97.0 % and 50.9 %, respectively, using 3.0 wt% fluorite (CaF2) powder (relative to the raw ore mass), 400 W microwave pretreatment for 3 min, 70 °C reaction temperature, 30 min reaction time, 4.0 mol/L sulfuric acid, 4:1 liquid–solid ratio (mL/g), and 300 rpm stirring speed. Therefore, microwave pretreatment significantly improves the leaching efficiencies of magnesium and iron in iron-bearing serpentine tailings with the assistance of fluorite. This is because hematite in the iron-bearing serpentine tailings is less reactive toward sulfuric acid in the conventional leaching process. By contrast, microwave irradiation alters the phase composition of hematite in the serpentine tailings, enhancing its reactivity with sulfuric acid and thus facilitating iron leaching.
{"title":"Microwave-enhanced leaching of magnesium and iron from iron-bearing serpentine tailings","authors":"Wenjia Kou , Wengang Liu , Wenbao Liu , Wei Zuo , Weichao Li","doi":"10.1016/j.hydromet.2025.106536","DOIUrl":"10.1016/j.hydromet.2025.106536","url":null,"abstract":"<div><div>To improve the utilization of valuable metal components in iron-bearing serpentine tailings, leaching experiments were conducted with microwave pretreatment, and the leaching conditions were optimized. The MgO and total Fe (Fe(II) and Fe(III)) leaching efficiencies reached 97.0 % and 50.9 %, respectively, using 3.0 wt% fluorite (CaF<sub>2</sub>) powder (relative to the raw ore mass), 400 W microwave pretreatment for 3 min, 70 °C reaction temperature, 30 min reaction time, 4.0 mol/L sulfuric acid, 4:1 liquid–solid ratio (mL/g), and 300 rpm stirring speed. Therefore, microwave pretreatment significantly improves the leaching efficiencies of magnesium and iron in iron-bearing serpentine tailings with the assistance of fluorite. This is because hematite in the iron-bearing serpentine tailings is less reactive toward sulfuric acid in the conventional leaching process. By contrast, microwave irradiation alters the phase composition of hematite in the serpentine tailings, enhancing its reactivity with sulfuric acid and thus facilitating iron leaching.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106536"},"PeriodicalIF":4.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750658","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 : 2025-07-26DOI: 10.1016/j.hydromet.2025.106549
Dongfeng Zhou , Shuai Rao , Xingbin Li , Niangao Teng , Zhigan Deng , Hongyang Cao , Dongxing Wang , Zhiyuan Ma , Zhiqiang Liu
Industrial extraction of Ga and Ge from zinc concentrate has been achieved; however, their recoveries remain relatively low because of dispersion during various procedures. This study thoroughly investigated the distribution behavior and precipitation mechanism of Ga and Ge from zinc pressure leachate into refinery residue. Process mineralogical investigations demonstrated that Ga primarily precipitated through the formation of jarosite, while Ge enrichment was driven by reduction using zinc powder. Controlling the terminal acidity within the range of 6.0–7.0 g/L during pre-neutralization effectively minimized jarosite formation, thereby reducing Ga loss to below 2.0 mg/L. The cementation process was further improved by introducing secondary zinc oxide, followed by zinc powder in a sequential manner. Strategic adjustment of the pH profile—beginning at 1.9–2.1 and concluding at 3.0–3.5—led to residual Ga and Ga concentrations of less than 2.0 mg/L and 1.0 mg/L, respectively. These conditions enabled production trials to achieve recovery efficiencies above 85 % for Ga and over 96 % for Ge.
{"title":"Enhanced gallium and germanium recovery from zinc pressure leachate via zinc powder cementation","authors":"Dongfeng Zhou , Shuai Rao , Xingbin Li , Niangao Teng , Zhigan Deng , Hongyang Cao , Dongxing Wang , Zhiyuan Ma , Zhiqiang Liu","doi":"10.1016/j.hydromet.2025.106549","DOIUrl":"10.1016/j.hydromet.2025.106549","url":null,"abstract":"<div><div>Industrial extraction of Ga and Ge from zinc concentrate has been achieved; however, their recoveries remain relatively low because of dispersion during various procedures. This study thoroughly investigated the distribution behavior and precipitation mechanism of Ga and Ge from zinc pressure leachate into refinery residue. Process mineralogical investigations demonstrated that Ga primarily precipitated through the formation of jarosite, while Ge enrichment was driven by reduction using zinc powder. Controlling the terminal acidity within the range of 6.0–7.0 g/L during pre-neutralization effectively minimized jarosite formation, thereby reducing Ga loss to below 2.0 mg/L. The cementation process was further improved by introducing secondary zinc oxide, followed by zinc powder in a sequential manner. Strategic adjustment of the pH profile—beginning at 1.9–2.1 and concluding at 3.0–3.5—led to residual Ga and Ga concentrations of less than 2.0 mg/L and 1.0 mg/L, respectively. These conditions enabled production trials to achieve recovery efficiencies above 85 % for Ga and over 96 % for Ge.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106549"},"PeriodicalIF":4.8,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724945","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 : 2025-07-24DOI: 10.1016/j.hydromet.2025.106548
E. Díaz-Gutiérrez , J. Hernández-Saz , José A. Maldonado Calvo , J.M. Gallardo , A. Paúl
The recovery of antimony from side stream is challenging due to impurities like arsenic and bismuth which affect extraction efficiency and product quality. This study examines the individual and combined effects of As and Bi on antimony hydrolysis from eluates produced during copper electrorefining. Synthetic and process eluates were analysed to optimise operating conditions and understand impurity interactions. Hydrolysis experiments across pH values (0.25–0.9) revealed an optimal pH range (0.6–0.7) for maximizing antimony recovery (>90 %) in impurity-free conditions. Arsenic reduced the antimony recovery by 8 %–13 %, destabilising precipitates and forming amorphous phases. Bismuth caused a smaller reduction (3 %–7 %) but had a diminished effect in the presence of As, which dominated the system's chemistry. Process eluates exhibited greater variability, particularly in extraction yields, underscoring the need to validate findings based on synthetic solutions against industrial matrices. This study provides insights into optimizing antimony recovery through impurity management and highlights the value of combining the analyses of synthetic and process eluates.
{"title":"Role of arsenic(V) and bismuth in the recovery of antimony by hydrolysis and precipitation from eluates produced during copper electrorefining","authors":"E. Díaz-Gutiérrez , J. Hernández-Saz , José A. Maldonado Calvo , J.M. Gallardo , A. Paúl","doi":"10.1016/j.hydromet.2025.106548","DOIUrl":"10.1016/j.hydromet.2025.106548","url":null,"abstract":"<div><div>The recovery of antimony from side stream is challenging due to impurities like arsenic and bismuth which affect extraction efficiency and product quality. This study examines the individual and combined effects of As and Bi on antimony hydrolysis from eluates produced during copper electrorefining. Synthetic and process eluates were analysed to optimise operating conditions and understand impurity interactions. Hydrolysis experiments across pH values (0.25–0.9) revealed an optimal pH range (0.6–0.7) for maximizing antimony recovery (>90 %) in impurity-free conditions. Arsenic reduced the antimony recovery by 8 %–13 %, destabilising precipitates and forming amorphous phases. Bismuth caused a smaller reduction (3 %–7 %) but had a diminished effect in the presence of As, which dominated the system's chemistry. Process eluates exhibited greater variability, particularly in extraction yields, underscoring the need to validate findings based on synthetic solutions against industrial matrices. This study provides insights into optimizing antimony recovery through impurity management and highlights the value of combining the analyses of synthetic and process eluates.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106548"},"PeriodicalIF":4.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724946","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 : 2025-07-24DOI: 10.1016/j.hydromet.2025.106539
Xinyuan Lan , Rong Liu , Liyan Xue , Minzhong Huang , Meiying Xie , Hongye Wang , Hao Zhang , Fan Yang
The efficient recovery of lithium (Li+) from salt lakes has become a pressing issue for the lithium battery industry. In this study, an electrochemically enhanced extraction system with industrialization potential was developed, which increased the separation efficiency of Li+ by coupling an electric field with ionic liquid extraction. A promising 1-butyl-3-methylimidazolium-2-thiophenecarbonyl trifluoroacetone ([C4mim][TTA]) extraction agent was developed. Furthermore, the functionalized ionic liquid (FIL) was dissolved in an ionic liquid mixture to further increase its extraction capacity. The separation performance and mechanisms of Li+ through [C4mim][TTA] liquid–liquid extraction were investigated. The results showed that within a pH range greater than 2, [C4mim][TTA] had a very high separation efficiency for Li+. Additionally, liquid–liquid extraction in solutions simulating the concentrations of Li+, Na+, and K+ found in salt lakes revealed very high Li+ separation coefficients of βLi/K = 3746 and βLi/Na = 1287. Under an applied electric field of 2.4 V, the electrochemically enhanced extraction system achieved separation coefficients of βLi/K = 6678 and βLi/Na = 3068 within 2 h, which represent the highest reported values to date. In this study, a novel electrochemically coupled ionic liquid extraction system with potential for industrialization is proposed.
{"title":"Enhancing Lithium extraction via ionic liquid coupled electrochemical methods","authors":"Xinyuan Lan , Rong Liu , Liyan Xue , Minzhong Huang , Meiying Xie , Hongye Wang , Hao Zhang , Fan Yang","doi":"10.1016/j.hydromet.2025.106539","DOIUrl":"10.1016/j.hydromet.2025.106539","url":null,"abstract":"<div><div>The efficient recovery of lithium (Li<sup>+</sup>) from salt lakes has become a pressing issue for the lithium battery industry. In this study, an electrochemically enhanced extraction system with industrialization potential was developed, which increased the separation efficiency of Li<sup>+</sup> by coupling an electric field with ionic liquid extraction. A promising 1-butyl-3-methylimidazolium-2-thiophenecarbonyl trifluoroacetone ([C<sub>4</sub>mim][TTA]) extraction agent was developed. Furthermore, the functionalized ionic liquid (FIL) was dissolved in an ionic liquid mixture to further increase its extraction capacity. The separation performance and mechanisms of Li<sup>+</sup> through [C<sub>4</sub>mim][TTA] liquid–liquid extraction were investigated. The results showed that within a pH range greater than 2, [C<sub>4</sub>mim][TTA] had a very high separation efficiency for Li<sup>+</sup>. Additionally, liquid–liquid extraction in solutions simulating the concentrations of Li<sup>+</sup>, Na<sup>+</sup>, and K<sup>+</sup> found in salt lakes revealed very high Li<sup>+</sup> separation coefficients of β<sub>Li/K</sub> = 3746 and β<sub>Li/Na</sub> = 1287. Under an applied electric field of 2.4 V, the electrochemically enhanced extraction system achieved separation coefficients of β<sub>Li/K</sub> = 6678 and β<sub>Li/Na</sub> = 3068 within 2 h, which represent the highest reported values to date. In this study, a novel electrochemically coupled ionic liquid extraction system with potential for industrialization is proposed.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106539"},"PeriodicalIF":4.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694575","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 : 2025-07-23DOI: 10.1016/j.hydromet.2025.106547
Gabriela Costa Caetano , Flávia Corrêa Rodrigues , Indianara Conceição Ostroski , Maria Angélica Simões Dornellas de Barros
Iron is a primary contaminant in the acid-leaching solution during lateritic nickel production. Additionally, the accumulation of pyrometallurgical tailings from conventional nickel ore processing presents a significant challenge for industrial mining operations. This study addresses these issues by utilizing ferronickel slags (refining slag and kiln dust) as alternative neutralizing agents for the precipitation and recovery of iron from sulfuric leaching solutions. A 23 factorial orthogonal experimental design, including two central points and six axial points, was employed to investigate the effects of agent concentrations on iron precipitation and nickel co-precipitation. The results were optimized based on response surface analysis and filtration resistance parameters. Slags and precipitated materials were characterized using XRD and XRF techniques, while initial and final liquors were analyzed via ICP-OES. Due to its high CaO content (58.33 wt%), the slag exhibited a neutralizing capacity comparable to commercial calcium and sodium carbonates. Optimal concentrations of slag (5.14 %) and kiln dust (25 %) achieved approximately 80 % removal of Fe2+/Fe3+, alongside a 46 % increase in Ni2+ recovery from the initial leaching solution. Precipitated iron oxides can be recovered through a reduction step, followed by washing or magnetic separation.
{"title":"Low-cost alternative for iron recovery in lateritic nickel production by using ferronickel refining slag and kiln dust for iron precipitation from acid leachate","authors":"Gabriela Costa Caetano , Flávia Corrêa Rodrigues , Indianara Conceição Ostroski , Maria Angélica Simões Dornellas de Barros","doi":"10.1016/j.hydromet.2025.106547","DOIUrl":"10.1016/j.hydromet.2025.106547","url":null,"abstract":"<div><div>Iron is a primary contaminant in the acid-leaching solution during lateritic nickel production. Additionally, the accumulation of pyrometallurgical tailings from conventional nickel ore processing presents a significant challenge for industrial mining operations. This study addresses these issues by utilizing ferronickel slags (refining slag and kiln dust) as alternative neutralizing agents for the precipitation and recovery of iron from sulfuric leaching solutions. A 2<sup>3</sup> factorial orthogonal experimental design, including two central points and six axial points, was employed to investigate the effects of agent concentrations on iron precipitation and nickel co-precipitation. The results were optimized based on response surface analysis and filtration resistance parameters. Slags and precipitated materials were characterized using XRD and XRF techniques, while initial and final liquors were analyzed via ICP-OES. Due to its high CaO content (58.33 wt%), the slag exhibited a neutralizing capacity comparable to commercial calcium and sodium carbonates. Optimal concentrations of slag (5.14 %) and kiln dust (25 %) achieved approximately 80 % removal of Fe<sup>2+</sup>/Fe<sup>3+</sup>, alongside a 46 % increase in Ni<sup>2+</sup> recovery from the initial leaching solution. Precipitated iron oxides can be recovered through a reduction step, followed by washing or magnetic separation.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106547"},"PeriodicalIF":4.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704153","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 : 2025-07-23DOI: 10.1016/j.hydromet.2025.106546
Zesen Zhao , Huiquan Li , Chenye Wang , Peng Xing
The recovery of nickel (Ni) and cobalt (Co) from laterite ores has attracted significant attention due to the increasing demand for these metals in electric vehicle (EV) batteries. While the sulfation-roasting-leaching process offers a viable route for extracting Ni and Co from laterite ores, the co-extraction of iron (Fe) remains a major challenge. To address this, the present study investigated the selective extraction of Ni and Co by optimizing equilibrium pH control and introducing stearyl trimethyl ammonium chloride (STAC), a cationic surfactant, during the leaching stage. Controlling the equilibrium pH of the slurry in the absence of STAC improved the selectivity of leaching Ni and Co over Fe. However, this pH adjustment also reduced the extraction of Ni and Co due to their adsorption onto hydroxide precipitates. Remarkably, the addition of STAC significantly enhanced Ni and Co recovery by modifying the surface properties of the leach residues. Mechanistic analysis revealed that STAC increased the zeta potential of the surface of residue particles and reduced particle agglomeration. These changes inhibited the adsorption and co-precipitation of Ni2+ and Co2+ with residues. Under optimized conditions (equilibrium pH 3.5 with 0.1 wt% STAC), the extraction reached 97.7 % for Ni and 97.4 % for Co, while Fe extraction was suppressed to 0.2 %. These results demonstrate a promising strategy for achieving high selectivity and efficiency in Ni/Co recovery from laterite ores, offering potential advantages over conventional hydrometallurgical approaches.
{"title":"Selective and efficient extraction of nickel and cobalt from laterite ores using the sulfation-roasting and leaching-precipitation process with H2O2 and surfactant addition","authors":"Zesen Zhao , Huiquan Li , Chenye Wang , Peng Xing","doi":"10.1016/j.hydromet.2025.106546","DOIUrl":"10.1016/j.hydromet.2025.106546","url":null,"abstract":"<div><div>The recovery of nickel (Ni) and cobalt (Co) from laterite ores has attracted significant attention due to the increasing demand for these metals in electric vehicle (EV) batteries. While the sulfation-roasting-leaching process offers a viable route for extracting Ni and Co from laterite ores, the co-extraction of iron (Fe) remains a major challenge. To address this, the present study investigated the selective extraction of Ni and Co by optimizing equilibrium pH control and introducing stearyl trimethyl ammonium chloride (STAC), a cationic surfactant, during the leaching stage. Controlling the equilibrium pH of the slurry in the absence of STAC improved the selectivity of leaching Ni and Co over Fe. However, this pH adjustment also reduced the extraction of Ni and Co due to their adsorption onto hydroxide precipitates. Remarkably, the addition of STAC significantly enhanced Ni and Co recovery by modifying the surface properties of the leach residues. Mechanistic analysis revealed that STAC increased the zeta potential of the surface of residue particles and reduced particle agglomeration. These changes inhibited the adsorption and co-precipitation of Ni<sup>2+</sup> and Co<sup>2+</sup> with residues. Under optimized conditions (equilibrium pH 3.5 with 0.1 wt% STAC), the extraction reached 97.7 % for Ni and 97.4 % for Co, while Fe extraction was suppressed to 0.2 %. These results demonstrate a promising strategy for achieving high selectivity and efficiency in Ni/Co recovery from laterite ores, offering potential advantages over conventional hydrometallurgical approaches.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106546"},"PeriodicalIF":4.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704159","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 : 2025-07-21DOI: 10.1016/j.hydromet.2025.106537
Qiong Ye , Fengshan Yu , Xunwei Ma , Jiashuang Wang , Kaihan Cai , Lincai Wang , Jian-Ping Zou
In response to the escalating scarcity of resources, the practice of recycling waste has emerged as a pivotal strategy for sustainable development. In the present study, an innovative method is introduced to enhance the recovery of platinum group metals (PGMs) from spent automotive catalysts (SACs), involving an integrated electrochemical metallurgy process integrating mechanochemical reduction pretreatment and electrochemical leaching. An in-depth exploration on the influences of mechanochemical ball-milling parameters and electrochemical leaching conditions on PGM recovery yielded insightful results. Notably, Zn emerges as a key catalyst to promote the generation of highly reactive PGM particles, facilitate grinding, reduce platinum group metal oxides, and alloy with PGMs. The mechanochemical reduction pretreatment significantly reduces the apparent dissolution activation energies of Pd, Pt, and Rh from 40.1 kJ/mol, 43.7 kJ/mol, and 62.5 kJ/mol to 13.2 kJ/mol, 17.5 kJ/mol, and 22.1 kJ/mol, respectively. Following optimization through orthogonal experiments, the leaching efficiencies of Pd, Pt, and Rh reached exceptional levels: 98.5 %, 98.1 %, and 93.3 %, respectively. This study unveils a highly efficient and practical approach for leaching PGMs from SACs, which is conducive to sustainable resource management.
{"title":"An electrometallurgical and mechanochemical approach for the recovery of platinum group metals from spent automotive catalysts","authors":"Qiong Ye , Fengshan Yu , Xunwei Ma , Jiashuang Wang , Kaihan Cai , Lincai Wang , Jian-Ping Zou","doi":"10.1016/j.hydromet.2025.106537","DOIUrl":"10.1016/j.hydromet.2025.106537","url":null,"abstract":"<div><div>In response to the escalating scarcity of resources, the practice of recycling waste has emerged as a pivotal strategy for sustainable development. In the present study, an innovative method is introduced to enhance the recovery of platinum group metals (PGMs) from spent automotive catalysts (SACs), involving an integrated electrochemical metallurgy process integrating mechanochemical reduction pretreatment and electrochemical leaching. An in-depth exploration on the influences of mechanochemical ball-milling parameters and electrochemical leaching conditions on PGM recovery yielded insightful results. Notably, Zn emerges as a key catalyst to promote the generation of highly reactive PGM particles, facilitate grinding, reduce platinum group metal oxides, and alloy with PGMs. The mechanochemical reduction pretreatment significantly reduces the apparent dissolution activation energies of Pd, Pt, and Rh from 40.1 kJ/mol, 43.7 kJ/mol, and 62.5 kJ/mol to 13.2 kJ/mol, 17.5 kJ/mol, and 22.1 kJ/mol, respectively. Following optimization through orthogonal experiments, the leaching efficiencies of Pd, Pt, and Rh reached exceptional levels: 98.5 %, 98.1 %, and 93.3 %, respectively. This study unveils a highly efficient and practical approach for leaching PGMs from SACs, which is conducive to sustainable resource management.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106537"},"PeriodicalIF":4.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704158","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 : 2025-07-20DOI: 10.1016/j.hydromet.2025.106538
Valentin Legrand, Stéphanie Szenknect, Olivier Diat, Luc Girard, Pierre Bauduin
The decomposition of scheelite in a synergistic H2SO4-H3PO4 mixture is an effective method for extracting tungsten from mining concentrates. The driving force behind the dissolution of scheelite in the H2SO4-H3PO4 mixture is the formation of a soluble Keggin-type polyoxotungstate, H3PW12O40, which prevents the formation of very low solubility tungstic acid. In this work, a multiparametric study of scheelite dissolution kinetics was carried out in a synergistic acid mixture. In particular, the independent contributions of temperature, acid concentration, and W:P molar ratio on scheelite dissolution kinetics and H3PW12O40 formation yield were evaluated. To this end, a method based on the use of small-angle X-ray scattering (SAXS) was developed to identify and quantify H3PW12O40 under different operating conditions. The results provide a better understanding of the stability range of H3PW12O40 in terms of H2SO4 concentration and stoichiometric W:P ratio. These findings led to the selection of optimized, soft-leaching conditions that ensure rapid dissolution of scheelite while avoiding surface passivation by the precipitation of secondary phases. A comparison with speciation calculations using thermodynamic data reported in the literature reveals an absence of a self-consistent thermodynamic dataset. Thus, measuring the concentration of H3PW12O40 in the leachate was necessary to optimize the dissolution conditions. From this perpective, SAXS appears to be a suitable quantitative method.
{"title":"Dissolution of scheelite under soft acidic conditions via the formation of polyoxotungstate: kinetics and mechanism supported by small-angle X-ray scattering (SAXS) to identify and quantify H3PW12O40","authors":"Valentin Legrand, Stéphanie Szenknect, Olivier Diat, Luc Girard, Pierre Bauduin","doi":"10.1016/j.hydromet.2025.106538","DOIUrl":"10.1016/j.hydromet.2025.106538","url":null,"abstract":"<div><div>The decomposition of scheelite in a synergistic H<sub>2</sub>SO<sub>4</sub>-H<sub>3</sub>PO<sub>4</sub> mixture is an effective method for extracting tungsten from mining concentrates. The driving force behind the dissolution of scheelite in the H<sub>2</sub>SO<sub>4</sub>-H<sub>3</sub>PO<sub>4</sub> mixture is the formation of a soluble Keggin-type polyoxotungstate, H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub>, which prevents the formation of very low solubility tungstic acid. In this work, a multiparametric study of scheelite dissolution kinetics was carried out in a synergistic acid mixture. In particular, the independent contributions of temperature, acid concentration, and W:P molar ratio on scheelite dissolution kinetics and H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> formation yield were evaluated. To this end, a method based on the use of small-angle X-ray scattering (SAXS) was developed to identify and quantify H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> under different operating conditions. The results provide a better understanding of the stability range of H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> in terms of H<sub>2</sub>SO<sub>4</sub> concentration and stoichiometric W:P ratio. These findings led to the selection of optimized, soft-leaching conditions that ensure rapid dissolution of scheelite while avoiding surface passivation by the precipitation of secondary phases. A comparison with speciation calculations using thermodynamic data reported in the literature reveals an absence of a self-consistent thermodynamic dataset. Thus, measuring the concentration of H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> in the leachate was necessary to optimize the dissolution conditions. From this perpective, SAXS appears to be a suitable quantitative method.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"237 ","pages":"Article 106538"},"PeriodicalIF":4.8,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664784","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 : 2025-07-16DOI: 10.1016/j.hydromet.2025.106534
Qiang Wang , Tong Liu , Ying Li , Yanhe Nie
The challenges associated with recovering gold from leachates restrict the wide applicability of thiosulfate systems. This study developed a facile one-step activation strategy for synthesizing coal-based activated carbon from low-cost, accessible bituminous coal precursors; the activated carbon was subsequently used to adsorb gold from thiosulfate solutions. The optimal conditions for synthesizing coal-based activated carbon were investigated, along with the effects of pH, temperature, and initial gold concentration on [Au(S2O3)2]3− adsorption by the coal-based activated carbon. The structural and surface properties of the adsorbent were analyzed before and after gold adsorption, which revealed that the initially smooth surface morphology of raw coal became porous after activation and that the surface was loaded with SCN groups. The adsorption process followed pseudo-second-order kinetics and was described using the Freundlich model. The adsorption of [Au(S2O3)2]3− on the coal-based activated carbon was a fast endothermic process. The adsorption equilibrium was attained within 60 min, at a gold concentration of 10 mg/L. The maximum adsorption capacity of gold on the coal-based activated carbon was 3.29 mg/g, at a gold concentration of 80 mg/L at 45 °C. During the gold adsorption, ligand exchange occurred between the [Au(S2O3)2]3− ions in the solution and the SCN groups on the coal-based activated-carbon surface, ultimately facilitating the adsorption of Au(I) in the solution on the activated-carbon surface. Moreover, the [Au(S2O3)2]3−-loaded coal-based activated carbon could be effectively eluted by thiosulfate. Hence, this study provides theoretical guidance and a practical basis for the adsorption of gold from thiosulfate leachates using coal-based activated carbon while facilitating clean, high-value utilization of coal resources.
{"title":"Synthesis of coal-based activated carbon via one-step activation and its adsorption and stripping performance for gold thiosulfate complexes","authors":"Qiang Wang , Tong Liu , Ying Li , Yanhe Nie","doi":"10.1016/j.hydromet.2025.106534","DOIUrl":"10.1016/j.hydromet.2025.106534","url":null,"abstract":"<div><div>The challenges associated with recovering gold from leachates restrict the wide applicability of thiosulfate systems. This study developed a facile one-step activation strategy for synthesizing coal-based activated carbon from low-cost, accessible bituminous coal precursors; the activated carbon was subsequently used to adsorb gold from thiosulfate solutions. The optimal conditions for synthesizing coal-based activated carbon were investigated, along with the effects of pH, temperature, and initial gold concentration on [Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub>]<sup>3−</sup> adsorption by the coal-based activated carbon. The structural and surface properties of the adsorbent were analyzed before and after gold adsorption, which revealed that the initially smooth surface morphology of raw coal became porous after activation and that the surface was loaded with <img>SCN groups. The adsorption process followed pseudo-second-order kinetics and was described using the Freundlich model. The adsorption of [Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub>]<sup>3−</sup> on the coal-based activated carbon was a fast endothermic process. The adsorption equilibrium was attained within 60 min, at a gold concentration of 10 mg/L. The maximum adsorption capacity of gold on the coal-based activated carbon was 3.29 mg/g, at a gold concentration of 80 mg/L at 45 °C. During the gold adsorption, ligand exchange occurred between the [Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub>]<sup>3−</sup> ions in the solution and the <img>SCN groups on the coal-based activated-carbon surface, ultimately facilitating the adsorption of Au(I) in the solution on the activated-carbon surface. Moreover, the [Au(S<sub>2</sub>O<sub>3</sub>)<sub>2</sub>]<sup>3−</sup>-loaded coal-based activated carbon could be effectively eluted by thiosulfate. Hence, this study provides theoretical guidance and a practical basis for the adsorption of gold from thiosulfate leachates using coal-based activated carbon while facilitating clean, high-value utilization of coal resources.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"236 ","pages":"Article 106534"},"PeriodicalIF":4.8,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656396","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 : 2025-07-14DOI: 10.1016/j.hydromet.2025.106535
Frank K. Crundwell
The dissolution of minerals is central to many fields of research interest, including hydrometallurgy, materials science, and geochemistry. The successful development of a comprehensive understanding of the mechanism of dissolution will have an impact on these fields. The challenge for the dissolution of gypsum is that rate of dissolution is proportional to the molar concentration of the dissolved salt, yet the solubility product is proportional to the square of the molar concentration of dissolved salt. Deriving an expression that is consistent with both the kinetics and thermodynamics has vexed researchers for decades. Furthermore, the zeta potential of gypsum shows no clear dependence on pH. In this paper, we show that the experimental data for the kinetics of dissolution, the thermodynamics describing the solubility product, and the zeta potential describing the surface charge are reconciled by accounting for the surface charge using the surface vacancy model of dissolution, and in doing so provide insight into the elementary steps involved in the dissolution of gypsum.
{"title":"On the mechanism of the dissolution of gypsum (calcium sulfate dihydrate)","authors":"Frank K. Crundwell","doi":"10.1016/j.hydromet.2025.106535","DOIUrl":"10.1016/j.hydromet.2025.106535","url":null,"abstract":"<div><div>The dissolution of minerals is central to many fields of research interest, including hydrometallurgy, materials science, and geochemistry. The successful development of a comprehensive understanding of the mechanism of dissolution will have an impact on these fields. The challenge for the dissolution of gypsum is that rate of dissolution is proportional to the molar concentration of the dissolved salt, yet the solubility product is proportional to the square of the molar concentration of dissolved salt. Deriving an expression that is consistent with both the kinetics and thermodynamics has vexed researchers for decades. Furthermore, the zeta potential of gypsum shows no clear dependence on pH. In this paper, we show that the experimental data for the kinetics of dissolution, the thermodynamics describing the solubility product, and the zeta potential describing the surface charge are reconciled by accounting for the surface charge using the surface vacancy model of dissolution, and in doing so provide insight into the elementary steps involved in the dissolution of gypsum.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"236 ","pages":"Article 106535"},"PeriodicalIF":4.8,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656395","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}
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