Hydrometallurgy最新文献

{"title":"Development of a conceptual direct solvent extraction (DSX) route and a flowsheet to produce purified concentrated cobalt and nickel solutions representing sulfuric acid leach liquor of laterite","authors":"Alexandre Silva Guimarães ,&nbsp;Georgio Patrício de Souza Resende ,&nbsp;Iranildes Daniel dos Santos ,&nbsp;Marcelo Borges Mansur","doi":"10.1016/j.hydromet.2024.106321","DOIUrl":"https://doi.org/10.1016/j.hydromet.2024.106321","url":null,"abstract":"<div><p>Direct solvent extraction (DSX) was applied to produce purified concentrated Ni and Co solutions from a synthetic sulfuric liquor containing Ca, Cu, Mg, Mn, and Zn as impurities, which simulates the solution obtained by the sulfation-roasting-leaching process after precipitation of Fe, Al, and Cr. The commercial extractants Versatic 10, Cyanex 272, D2EHPA, TBP were used in 3 solvent extraction circuits. In the first circuit, operated at 40 °C, Versatic 10 (0.5 M) fully extracted Cu, Zn, Ni, and Co in 3 stages at O/A = 2:1, and pH 6.5, leaving remaining Mn (54% was extracted) and most of the Ca and Mg in the raffinate. The co-extracted Ca and Mg were fully scrubbed off the loaded Versatic 10 in 2 stages at O/A = 5:1, and pH 6.5. The other metals were stripped out of the Versatic 10 extract using a synthetic Ni spent electrolyte (60 g/L Ni, 2 M H₂SO₄) in 2 stages at O/A = 9:1. This loaded strip liquor was subjected to a second circuit with Cyanex 272 (0.64 M) operated at 50 °C. Three stages were required to fully extract Co, Cu, Mn, and Zn (O/A = 2:1, pH 4), whereas the raffinate containing 82 g/L Ni was deemed suitable for electrowinning. The co-extracted Ni(II) was fully scrubbed off the loaded Cyanex 272 in only 1 stage at O/A = 5:1, and pH 4. All Co, Cu, Mn, and Zn were stripped out from the scrubbed loaded Cyanex 272 in 2 stages at O/A = 10:1 using a synthetic Co spent electrolyte (45 g/L Co, 1 M H₂SO₄). The raffinate containing 58.4 g/L Co was submitted to a third circuit using a D2EHPA (0.6 M) + TBP (0.73 M) synergistic system operated at 50 °C. Zinc(II) was fully extracted by the D2EHPA + TBP system in 2 stages at pH 2 and O/A = 1:3, while Mn(II) and Cu(II) were fully extracted from the Zn-depleted raffinate in 2 stages at pH 3.5 and O/A = 2:1. The raffinate containing 58.3 g/L Co was deemed suitable for electrowinning. Copper(II), Mn(II), and Zn(II) were stripped out from the loaded D2EHPA + TBP in 3 stages at O/A = 2.5:1 using 1 M H₂SO₄. The real number of moles of extractants involved in the extractions and apparent equilibrium constants were estimated for all circuits. A flowsheet of the purification conceptual route is presented.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"227 ","pages":"Article 106321"},"PeriodicalIF":4.7,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140645016","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":"Simultaneous extraction of molybdenum and silicon from sulphate leach solution of spent catalyst using trialkylamine (N235) and recovery of pure ammonium molybdate","authors":"Wenhui Shi ,&nbsp;Jian Li ,&nbsp;Yaobin Lai ,&nbsp;Hui Zhang ,&nbsp;Huadong Zhang ,&nbsp;Xuxia Zhang ,&nbsp;Kejia Liu ,&nbsp;Tao Qi","doi":"10.1016/j.hydromet.2024.106308","DOIUrl":"10.1016/j.hydromet.2024.106308","url":null,"abstract":"<div><p>Spent catalyst of molybdenum with silicon dioxide, commonly used as the carrier, is an important secondary resource for recovery of molybdenum. This work proposes a process to recycle molybdenum and remove silicon simultaneously by solvent extraction. The sulfuric acid leachate of the spent catalyst was contacted with the trialkylamine N235 (R₃N, R = C₈–C₁₀), to extract molybdenum and silicon. Several vital parameters were investigated to explore the influence on extraction and stripping. The extraction efficiencies of molybdenum and silicon were up to 99.6% and 77.1% after three-stage countercurrent extraction under optimized condition. The extraction reactions were determined by maximum loading capacity and FT-IR. The peak at 802.1 cm⁻¹ was caused by the stretching vibration of Si-O-Si, indicating the co-extraction of silicon. Molybdenum and silicon in the loaded organic phase can be stripped by the mixture of solution containing 7.00 mol/L NH₄OH and 0.80 mol/L (NH₄)₂CO₃, and the stripping efficiencies were &gt;99.0%. Ammonium molybdate was prepared by removing silicon and evaporating, and the purity was 99.9%.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"227 ","pages":"Article 106308"},"PeriodicalIF":4.7,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140780541","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":"Behavior of calcium lignosulfonate under oxygen pressure acid leaching condition","authors":"Sijie Yang,&nbsp;Yuhu Li,&nbsp;Yudong Yang,&nbsp;Ran Liu,&nbsp;Yi Zhao","doi":"10.1016/j.hydromet.2024.106317","DOIUrl":"10.1016/j.hydromet.2024.106317","url":null,"abstract":"<div><p>The behavior of calcium lignosulfonate (CLS) in the oxygen pressure acid leaching process of ZnS concentrate was investigated using total organic carbon assessment (TOC), UV–visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), and gas chromatography-coupled mass spectrometry (GC–MS) as characterization methods. The effect of the CLS degradation products on zinc electrowinning was also discussed. The results showed that the temperature was positively correlated with the degradation of CLS, while the initial acidity had only significant effects in the range of 0–50 g/L and oxygen partial pressure range of 0–0.1 MPa. At an oxygen partial pressure of 0.2 MPa, an acidity of 160 g/L, and a reaction temperature of 150 °C, about 82.4% of CLS was degraded. In the oxygen pressure acid leaching process, CLS underwent polymerization and decomposition reactions, and its aromatic rings and side chain groups were damaged to varying degrees. At 120 °C, CLS was partially converted into sulfonic acids, phenols, and esters of higher molecular weights. At 150 °C, CLS further degraded into lower-molecular-weight aromatic ethers and sulfonic acids with shorter carbon chains. These organics were relatively stable and were the main sources of organic compounds during the oxygen pressure leaching process of zinc concentrates. The addition of CLS had a significant negative impact on zinc electrowinning, which was related to the adsorption of CLS on the cathode surface, enhancing cathodic polarization and inhibiting zinc reduction kinetics.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"227 ","pages":"Article 106317"},"PeriodicalIF":4.7,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140759755","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":"Mechanism of the denitrification of secondary aluminum dross (SAD) during water leaching with delayed addition of a low dosage of sodium hydroxide","authors":"Chuan Wang ,&nbsp;Yongchun Guo ,&nbsp;YongYi He ,&nbsp;Sen Li ,&nbsp;Jun Liu ,&nbsp;Hu Liu","doi":"10.1016/j.hydromet.2024.106318","DOIUrl":"10.1016/j.hydromet.2024.106318","url":null,"abstract":"<div><p>Secondary aluminum dross (SAD) has been identified as a hazardous waste because it contains refractory AlN, fluoride, and other salts. Considering that Al(OH)₃ produced during the hydrolysis of AlN in SAD hinders spontaneous AlN hydrolysis, which is amplified by the partial embedment of AlN in other oxide phases present in SAD particles, the complete removal of AlN from SAD is difficult. Herein, we propose a new catalytic hydrolytic denitrification process of SAD, which requires a low additive dose. By changing the time at which the additive (NaOH) was added to the SAD slurry, the proportion of nitrogen removed from SAD was increased. The additive (NaOH) reacted with Al(OH)₃, thereby mitigating its hindering effect on spontaneous AlN hydrolysis and facilitating the complete hydrolysis of the semi-encapsulated AlN in SAD particles. Concurrently, the reaction between NaOH and Al₂O₃ and SiO₂ phases present in SAD was mitigated, resulting in the maximal retention of residual materials (phases other than Al resources) in the solid phase. A SAD denitrification efficiency of 99.0% was achieved under optimal processing conditions (<em>T</em> = 95 °C, <em>t</em> = 240 min, Liquid-to-solid ratio = 6:1, stirring speed = 400 rpm, and the addition of 7 wt% NaOH at 0.5 h), and a slightly lower efficiency of 98.2% was achieved when 50% lower amount of NaOH (3 wt%) was used. Thus, approximately 50% less additive is required for nitrogen removal from SAD, relative to that used in traditional catalytic water-washing processes.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106318"},"PeriodicalIF":4.7,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637751","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":"Selective leaching behavior of Nd from spent NdFeB magnets treated with combination of selective oxidation and roasting processes","authors":"Bosung Seo ,&nbsp;Hyung-Ki Park ,&nbsp;Taewook Na ,&nbsp;Seojin Heo ,&nbsp;Rina Kim ,&nbsp;Ho-Sung Yoon ,&nbsp;Kyeong Woo Chung ,&nbsp;Kwangsuk Park","doi":"10.1016/j.hydromet.2024.106320","DOIUrl":"10.1016/j.hydromet.2024.106320","url":null,"abstract":"<div><p>Selective leaching behavior of the spent NdFeB magnets was investigated to find out how controlled phase system through the roasting conditions gave an impact on the performance of the selective leaching. The pre-formed Nd₂O₃ by the selective oxidation made it possible to prevent the formation of NdFeO₃ at high roasting temperature. This resulted in the ideal Nd₂O₃ and Fe₂O₃ phase system, which was obtained by roasting at 660 °C, suitable for the selective leaching of Nd. While the roasting at 600 °C was still not enough to get full oxidation, the roasting at 720 °C made the NdFeO₃ formed. These characteristics with the roasting conditions affected leaching behavior. The NdFeB powder sample of 32 μm particle diameter, roasted at 600 °C showed the highest Nd leaching efficiency as well as the highest Fe leaching efficiency, which seemed to be ascribed to the existence of the metallic Fe. The poor leaching efficiency for the large powder size after roasting was ascribed to the poor diffusion characteristic of the H₂SO₄ solution. With the controlled phase system, the 100% leaching efficiency of Nd could be obtained by reducing the particle size to 16 μm. The formation of NdFeO₃ as a co-product, which had resistance to the reaction with the leaching agent, could prevent the dissolution of Nd₂O₃ around the NdFeO₃ layer. Thus, the 720 °C roasting condition showed the lowest leaching efficiency. The co-product Fe₂O₃ also showed good resistance to leaching so its leaching efficiency was just 5–6% after the leaching time of 3–4 h.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"227 ","pages":"Article 106320"},"PeriodicalIF":4.7,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140767312","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":"Review of leaching, separation and recovery of vanadium from roasted products of vanadium slag","authors":"Changqing Li ,&nbsp;Tao Jiang ,&nbsp;Jing Wen ,&nbsp;Tangxia Yu ,&nbsp;Feifei Li","doi":"10.1016/j.hydromet.2024.106313","DOIUrl":"10.1016/j.hydromet.2024.106313","url":null,"abstract":"<div><p>Vanadium is a strategic metal with extensive applications in steel production and emerging energy technologies. In vanadium metallurgy, the pivotal steps encompass the roasting of vanadium slag, leaching, and precipitation of vanadium. The roasting process, which involves elements such as sodium, calcium, manganese, and magnesium, facilitates the phase transformation and extraction of vanadium. Considering the phase separation behavior of vanadium-enriched phases (MV₂O₆, MV₂O₇, or MV₂O₈) in various leaching media, including acid, alkali, and water, the wet decomposition of these phases can be classified into two categories: (i) those yielding insoluble M and soluble V and (ii) those resulting in both soluble M and V. Thermodynamically, the reaction equilibrium constants and temperature profiles of the vanadium-rich phases in various acid and alkaline decomposition processes were calculated and juxtaposed. This review also reports the limiting factors of leaching kinetics of vanadium-rich phases in acid and alkaline decomposition processes, particularly the separation and transformation of vanadium-rich phases in calcified vanadium slag. The vanadium precipitation process encompasses a detailed elaboration of the mechanisms behind the precipitation of hydrolyzed vanadium product and ammonium‑vanadium product. Finally, the vanadium slag roasting-leaching‑vanadium precipitation process was evaluated from four aspects: principle, laboratory and plant practice, resource and environment, and cost and benefit.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106313"},"PeriodicalIF":4.7,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140637747","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":"Reductive leaching of bauxite residue and subsequent scandium extraction by sulphuric acid leaching – Preliminary evaluation","authors":"A. Shoppert ,&nbsp;D. Valeev ,&nbsp;M.M. Diallo ,&nbsp;J. Napol'skikh ,&nbsp;I. Loginova","doi":"10.1016/j.hydromet.2024.106315","DOIUrl":"https://doi.org/10.1016/j.hydromet.2024.106315","url":null,"abstract":"<div><p>Bauxite residue (BR) is a by-product of bauxite refining using Bayer process for alumina production, which contains numerous valuable components: iron (Fe), aluminum (Al), and rare earth elements such as scandium (Sc). The main issue of previous research for the Sc extraction from BR was the low extraction efficiency or high Fe co-extraction. This article shows that Fe co-extraction can be significantly reduced after reductive leaching of BR in the presence of Fe(II). This effect was achieved due to the formation of magnetite (Fe₃O₄) after reductive leaching of bauxite. Magnetite is practically insoluble in H₂SO₄ at pH &gt; 2. The effect of temperature (T), time (t) and liquid to solid ratio (L:S ratio) on the leaching process was revealed. The results show that under optimum conditions (pH = 2, <em>T</em> = 90 °C, <em>t</em> = 2 h, L:S ratio = 10:1), Sc extraction can reach 57%, with a simultaneous co-extraction of Fe &lt;1.3%. At the same parameters about 10% of Fe is extracted from the raw BR. The Fe content in the residue after leaching increased from 58.3 to 66.2 wt%, corresponding to the iron concentrate. Thus, the Sc extraction from a modified BR by dilute H₂SO₄ creates the conditions for the complete valorization of this technogenic waste, and improved extraction selectivity.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106315"},"PeriodicalIF":4.7,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140631681","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":"Dibutylamide hydrophobic deep eutectic solvent used for selective extraction of Au(III) from hydrochloric acid medium","authors":"Ronghao Liu,&nbsp;Jun Li,&nbsp;Xiaoxia Liu,&nbsp;Xiaolu Yin,&nbsp;Yanzhao Yang","doi":"10.1016/j.hydromet.2024.106312","DOIUrl":"https://doi.org/10.1016/j.hydromet.2024.106312","url":null,"abstract":"<div><p>The effective and environmentally friendly recovery of gold from secondary resources has recently received increased attention. Hydrophobic deep eutectic solvent (HDES) composed of <em>N</em>,<em>N</em>-di-butylacetamide and 1-decanoic acid was used to construct the liquid-liquid extraction system to extract Au(III) from HCl medium. At first, DSC, TGA, FT-IR, and ¹H NMR were used to describe the evidence of internal hydrogen bond interaction. The above evidence was verified in the molecular dynamics study of HDES. Then, a series of optimization experiments were carried out to investigate the extraction behaviors of HDES. Based on the results of optimization experiments, response surface method was used to explore the best experimental conditions and the results showed that HDES extracted 99% Au(III) under 0.56 mol/L HCl, 2.19 mol/L NaCl, and 5.83 mmol/L Au(III), and the maximum loading reached 77.0 mg/g. Further studies on the kinetics and thermodynamics of the extraction were used to propose an ion association mechanism. In addition, using 0.1 mol/L thiourea as the stripping agent, HDES displayed outstanding Au(III) selectivity and maintained the extraction efficiency in tests which involved 5-cycles. Overall, this study provides a green and efficient Au(III) recovery strategy for secondary resources.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106312"},"PeriodicalIF":4.7,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140604474","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 bidentate diamide ligand DODQ for the separation of uranium and rare earth ions in nitric acid medium","authors":"Miaomiao Zhang ,&nbsp;Zhen Yang ,&nbsp;Jianhui Su ,&nbsp;Heng Zhao ,&nbsp;Chengjin Xu ,&nbsp;Jiahui Sun ,&nbsp;Xiaolei Liu ,&nbsp;Xiujing Peng ,&nbsp;Guoxin Sun ,&nbsp;Yu Cui","doi":"10.1016/j.hydromet.2024.106311","DOIUrl":"https://doi.org/10.1016/j.hydromet.2024.106311","url":null,"abstract":"<div><p>High efficiency extractants play a necessary role in the selective removal of uranium from rare earth minerals. In this paper, a novel cyclic bidentate diamine extractant, 1, 4-dioctyl-1, 4-dihydroquinoxaline-2, 3-dione (DODQ), was synthesized, and the complexation and extraction of UO₂²⁺ in nitric acid medium were systematically studied. The results indicate that DODQ exhibits a unique combination of properties in removing UO₂²⁺, with an extraction capacity 132 times higher than that of DODPhOA (acyclic structure). Extraction isotherm experiments and slope analyses illustrate the formation of a 1:1 DODQ/UO₂²⁺ regime during the extraction process. Electrospray mass spectrometry, fluorescence spectroscopy, and X-ray crystal diffraction analyses further corroborated its stoichiometric properties. In addition, DODQ can remove UO₂²⁺ from rare earth solutions containing UO₂²⁺ with high selectivity. This study provides an alternative method to separate uranium from the leaching solution of rare earth ore and has a new understanding of the coordination and complexing behavior of UO₂²⁺ with bidentate oxygen-containing ligands.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106311"},"PeriodicalIF":4.7,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622213","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":"Effect of mechanical activation and HNO3 pre-treatment of Pulmoddai ilmenite for the extraction of Ti and TiO2 using H2SO4, HCl, and KOH-assisted leaching","authors":"G.N.T. Jayalath ,&nbsp;U.G.T. Nishadini ,&nbsp;H.M.B.N. Wickramasooriya ,&nbsp;H.C.S. Subasinghe,&nbsp;Amila Sandaruwan Ratnayake","doi":"10.1016/j.hydromet.2024.106314","DOIUrl":"https://doi.org/10.1016/j.hydromet.2024.106314","url":null,"abstract":"<div><p>Mild leaching with HNO₃ acid can be suggested as a potential pre-treatment technique for removing most impurities found in ilmenite which has not been properly investigated yet. This study examines the mild HNO₃ leaching behavior of ball-milled ilmenite as a novel pre-treatment method to produce high-purity synthetic rutile. Ilmenite was mechanically activated for 1 h at 500 rpm which was then reacted with 1 M HNO₃ acid solution in the solid-to-liquid ratio (S/L) of 1:5 (<em>w</em>/<em>v</em>) at 90 °C, 300 rpm, for 2 h to obtain pretreated (ball-milled and ball-milled-mild-leached) ilmenite. The ball-milled ilmenite and ball-milled-mild-leached ilmenite were then reacted with varying concentrations of H₂SO₄, HCl, and KOH solutions at predetermined conditions. Titanium and iron extraction, TiO₂ purity, phase transformations, surface morphologies, and relative elemental abundances were determined by atomic absorption spectroscopy (AAS), X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope equipped with an energy-dispersive X-ray spectroscopy (SEM/EDX), respectively. The initial mild leaching process removed V₂O₅, MgO, MnO, CaO, and Al₂O₃ impurities. The crystallinity indices of ball-milled ilmenite (39.7%) and ball-milled-mild-leached ilmenite (56.7%) indicate the effect of ball milling and mild leaching, respectively. The maximum Ti extraction of ball-milled-mild-leached ilmenite obtained from the sulfate method, chloride method, and alkaline method were 62.1%, 13.2%, and 41.8%, respectively. However, the Ti extraction of ball-milled-mild-leached ilmenite is relatively low compared to ball-milled ilmenite based on percentage extractions. Therefore, the HNO₃ mild leaching process is important to remove impurities, and mechanical activation is more suitable for efficient Ti extraction than a combined step with leaching.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"226 ","pages":"Article 106314"},"PeriodicalIF":4.7,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140604475","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}