Hydrometallurgy最新文献

{"title":"Selective extraction of uranium from nitric acid leachate of Minjingu rock phosphate","authors":"Raghav S. Soni ,&nbsp;Hitarth K. Thakkar ,&nbsp;Nils H. Haneklaus ,&nbsp;Dennis A. Mwalongo ,&nbsp;Ashwin W. Patwardhan ,&nbsp;Pushpito K. Ghosh","doi":"10.1016/j.hydromet.2025.106448","DOIUrl":"10.1016/j.hydromet.2025.106448","url":null,"abstract":"<div><div>A sample of beneficiated rock phosphate from Minjingu Mine and Fertilizer Plant, Tanzania was analysed by energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy and found to contain 15.8 % and 5.30 × 10⁻² % <em>w/w</em> P₂O₅ and U, respectively. The U content of the same sample was estimated to be 3.70 × 10⁻² % <em>w/w</em> when the digested mass was analysed by inductively coupled plasma mass spectrometry (ICP-MS). The rock was leached with three different mineral acids at 65–70 °C. The outlet liquid and solid streams were analysed by ICP-MS and ED-XRF, respectively. Maximum leaching of P₂O₅ and U occurred with 8.9 M HNO₃. Their respective concentrations in the leachate were 6.69 % <em>w/w</em> (99.0 g L⁻¹) and 1.80 × 10⁻² % <em>w/w</em> (0.27 g L⁻¹). The leachate also contained 1.90 × 10⁻² % <em>w/w</em> (0.28 g L⁻¹) rare earth elements (REEs). Selective extraction of U was attempted employing Di-2-ethyl hexyl phosphoric acid (D2EHPA) and Tri-butyl phosphate (TBP) as co-extractants. A 2-stage cross-current solvent extraction (10 g scale; 30 °C) with 1:6 mol ratio of D2EHPA:TBP (0.14 M total extractant concentration; 1:1 <em>w/w</em> organic/aqueous ratio) gave 81–89 % U extraction without co-extraction of REEs. The extraction of U increased to 95.6 % after four stages of solvent extraction but there was a noticeable co-extraction of Y beyond the first two stages. Production of fertilizers from U-free leachate is environmentally safer and the recovered U, in pure form, can be used for fuel production.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"233 ","pages":"Article 106448"},"PeriodicalIF":4.8,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379167","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":"Scandium extraction from sulfate media with di-(2-ethylhexyl) phosphoric acid in decane or toluene mixed with proton-donor additives","authors":"N.A. Grigorieva ,&nbsp;I.Yu. Fleitlikh ,&nbsp;O.A. Logutenko ,&nbsp;T.Yu. Ivanenko ,&nbsp;S.A. Novikova","doi":"10.1016/j.hydromet.2024.106435","DOIUrl":"10.1016/j.hydromet.2024.106435","url":null,"abstract":"<div><div>In this work, the effect of proton-donor additives (monocarboxylic acids, aliphatic alcohols, and phenol derivatives) on scandium extraction from sulfate solutions with di-(2-ethylhexyl)phosphoric acid (D2EHPA, HR) in decane or toluene as the diluent was investigated. It was shown that addition of these additives into the organic phase leads to an antagonistic effect, i.e., to a decrease in the extraction of scandium, and thus improves the stripping efficiency. The antagonistic effect decreases in the series octanol &gt;4-t-butylphenol &gt; &gt; octanoic acid. The low activity of octanoic acid is due to self-association, which significantly prevents the formation of intermolecular associates between D2EHPA and the monocarboxylic acid. Alcohols and phenols form stable associates with D2EHPA, which leads to a decrease in scandium extraction. Analysis of the interphase scandium distribution as well as the nuclear magnetic resonance (NMR) and infrared (IR) spectra of the loaded organic phases showed that the composition of the extracted scandium compound in the mixed extractant system containing D2EHPA and octyl alcohol is ScR₃. In the case of D2EHPA in inert diluents (such as decane and toluene), the composition of the extracted scandium compound in excess extractant is Sc(HR₂)₃. Scandium stripping from the D2EHPA and octyl alcohol mixtures with a sulfuric acid solution is almost impossible, but it can be successfully achieved with an alkaline solution containing sorbitol. In this case, no precipitation occurs in the organic phase which is an advantage. Extraction systems containing D2EHPA and higher alcohols, such as 2-ethylhexanol, can be used to recover scandium from various industrial solutions.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106435"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157117","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":"Cost effective selective separation of indium and germanium from zinc processing waste leach liquor using D2EHPA-YW100 synergistic system and selective stripping with HCl and NH4F","authors":"Chen Wang ,&nbsp;Junxian Hu ,&nbsp;Keyu Zhang ,&nbsp;Shaoze Zhang ,&nbsp;Yin Li ,&nbsp;Yaochun Yao","doi":"10.1016/j.hydromet.2024.106421","DOIUrl":"10.1016/j.hydromet.2024.106421","url":null,"abstract":"<div><div>Indium and germanium are rare elements and contribute to supporting materials for contemporary high technology new materials. Research and development of efficient separation and extraction of indium and germanium have important practical significance. A new process of “one step extraction and stepwise stripping” is proposed in this work to coextract indium and germanium with D2EHPA-YW100 synergistic system of Di(2-ethylhexyl) phosphoric acid (D2EHPA) and C7–9 hydroxamic acid (YW100) denoted by D2EHPA-YW100. In the coextraction process, 98.9 % of indium and 99.9 % germanium were extracted utilizing an organic phase consisting of YW100 (1.4 %), D2EHPA (15 %) and sulfonated kerosene (83.6 %). During the two-step stripping process, 99.9 % of indium was selectively stripped from the loaded organic phase in step-1 using 4 M HCl. In step-2, 99.5 % of germanium was stripped using a 1 M NH₄F solution. This separation resulted the enrichment of germanium concentration by 6–7 fold and indium concentration by 19 fold. This method has four advantages: (i) simplifies the separation process, (ii) reduces equipment investment by nearly 50 %, (iii) minimizes extraction agent loss, and (iv) reduces management and labor costs.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106421"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157542","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":"Pilot plant study on manganese bioleaching using biomass decomposition products as a nutrient source and electrolysis for oxide precipitation","authors":"Palas Kamlakar Borkar,&nbsp;Neha Sharma,&nbsp;Stephen Techtmann,&nbsp;Timothy Eisele","doi":"10.1016/j.hydromet.2024.106430","DOIUrl":"10.1016/j.hydromet.2024.106430","url":null,"abstract":"<div><div>Manganese leaching was carried out on a small pilot scale with 110 kg of ore using manganese-reducing organisms and fermentative organisms with biomass (<em>Typha latifolia</em>) as the source of nutrition. This study was carried out without externally supplied chemical reagents and with minimal capital investment. The process involves fermentative organisms to ferment biomass from <em>T. latifolia</em> and generate organic acids. Manganese-reducing organisms and organic acids reduced and dissolved manganese from pyrolusite ore. Manganese was precipitated from the manganese-bearing solution using an electrolytic oxidation technique.</div><div>A manganese concentration above 500 mg/L and negligible dissolved iron was achieved at a flow rate of 30 L/day, maintaining a pH range of 4 to 5, and a redox potential between 0.10 and 0.46 V. Manganese oxide was produced at a rate of 12 g/day, with a purity of 90 %. Amorphous manganese oxide was deposited on the cathode, while crystalline manganese oxide formed on the anode.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106430"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157543","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":"Extraction of Au(I) from a thiosulfate leach liquor using guanidinium ionic liquid (C8)2dmg+Br− in 20 % (v/v) n-octanol/n-heptane diluent and stripping with aqueous NaCl","authors":"Lingli Liu ,&nbsp;Guiping Zhu ,&nbsp;Chen He,&nbsp;Yanjun Chen,&nbsp;Yewei Qiu,&nbsp;Shixiong Wang,&nbsp;Conghai Zhang,&nbsp;Xiangjun Yang","doi":"10.1016/j.hydromet.2024.106432","DOIUrl":"10.1016/j.hydromet.2024.106432","url":null,"abstract":"<div><div>In this study, novel guanidinium ionic liquids (GILs) were designed to achieve efficient extraction of Au(I) from thiosulfate solution. A series of process parameters affecting extraction efficiency, including reaction time, phase ratio, different types of guanidinium ionic liquids and their concentrations, as well as different stripping agents, were tested. The results showed that 2,2-dioctyl-1,1,3,3-tetramethylguanidinium bromide (C₈)₂dmg⁺Br⁻) dissolved in 20 % (<em>v</em>/v) n-octanol/n-heptane diluent exhibited excellent extraction performance for Au(I) under optimal extraction conditions. The extraction efficiency of Au(I) in thiosulfate solution was over 98.7 % at aqueous/organic phase volume ratio (R_A/O) of 2. By combining Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), it was established that the extraction of Au(I) followed the mechanism of anion exchange and electrostatic attraction. The extraction efficiency of Au(I) by (C₈)₂dmg⁺Br⁻ was substantially superior to Cu(II), Ni(II), Mn(II), Fe(III) and Co(III) in the thiosulfate leach liquor, showing remarkable selectivity for Au(I). In addition, gold in the loaded GIL phase can be efficiently stripped by NaCl solution. The newly developed extraction system had excellent recycling performance and environmental friendliness, which still maintained high gold extraction efficiency after five extraction/stripping cycles. These results confirmed that the GIL-based extraction system provides a feasible method for green and efficient gold extraction from thiosulfate solution and has a good application prospect.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106432"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157546","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":"Enhancement of mass transfer process in column leaching by graded combination of coarse–medium–fine (C–M–F) particle packing: Application to heap leaching of ion-adsorption type rare earth ore with mixed (NH4)2SO4 and NH4Cl solution","authors":"Defeng Liu ,&nbsp;Yuzhi Wang ,&nbsp;Zhenyue Zhang ,&nbsp;Ruan Chi","doi":"10.1016/j.hydromet.2025.106436","DOIUrl":"10.1016/j.hydromet.2025.106436","url":null,"abstract":"<div><div>The heap leaching of ion-adsorption type rare earth (RE) ores confronts the problems of the poor extent of leaching and high reagent consumption. This work explored the optimization of the mass transfer process by mixed-ammonium salt leaching of RE ore samples based on the column-packing order of particle size, chromatographic plate theory, and hierarchical column leaching experiments. Furthermore, the parameters of the mass transfer process during heap leaching with the mixed-ammonium salts were optimized. Additionally, the enhancement mechanism of the mass transfer process of the preferred hierarchical ore samples was identified using the Avizo software. Results indicated that a layered and graded combination of coarse–medium–fine (C–M–F) ore samples was the best for the RE leaching effect. The optimal leaching process parameters for RE were a molar ratio of 3:1 between (NH₄)₂SO₄ and NH₄Cl, ammonium ion concentration of 0.3 mol/L, leaching temperature of 303.15–313.15 K, pH of 4–6 for the leaching agent and flow rate of 0.5 mL/min. The diffusion channels of the solute in the C–M–F samples during leaching were more even than those in the raw ore samples. Meanwhile, its average pore pressure was relatively low. The research results can provide useful theoretical references and technical support for in-situ heap leaching of RE, gold, copper and other metal elements.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106436"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157109","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 effect of persistent exposure to thiocyanate and the impact on inhibition of ferrous iron oxidation in an industrial strain of Acidiplasma cupricumulans","authors":"Catherine J. Edward ,&nbsp;Athanasios Kotsiopoulos ,&nbsp;Susan T.L. Harrison","doi":"10.1016/j.hydromet.2024.106431","DOIUrl":"10.1016/j.hydromet.2024.106431","url":null,"abstract":"<div><div><em>Acidiplasma cupricumulans</em> is recorded as an acidophilic chemomixotrophic iron-oxidising archaeal species that is prevalent within the mineral biooxidation community. The archaeal strain was persistently exposed to 1 mg/L of SCN⁻, a toxic anion present in low concentrations in remediated cyanidation tailings wastewater from gold recovery plants, to potentially facilitate adaptation. Adaptation to a concentration of 1 mg/L SCN⁻ was induced. The performance data of the thiocyanate-adapted strain was compared with that of the control strain to characterise the evolutionary change in microbial activity. Adaptation to SCN⁻ altered microbial growth, producing an elevated <span><math><msub><mi>Y</mi><mi>xs</mi></msub></math></span> which possibly denoted an upregulation within the central carbon metabolism. Furthermore, adaptation suppressed the rate of Fe²⁺ oxidation. As such, the Fe²⁺ oxidation rate expression developed previously for <em>Ap. cupricumulans</em> was not suitable and required modification of the kinetic constant (<span><math><msub><mi>K</mi><msup><mi>Fe</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></msub></math></span>) to account for the observed reduction in substrate affinity. The updated <span><math><msub><mi>K</mi><msup><mi>Fe</mi><mrow><mn>2</mn><mo>+</mo></mrow></msup></msub></math></span> was ∼3 times larger which aligned with the suspected bioenergetic burden. In addition, the inhibition kinetics of the adapted strain were evaluated across a SCN⁻ range of 0–3.0 mg/L to quantify changes in microbial resilience. The inhibition mechanism remained unchanged, with Fe²⁺ oxidation activity non-competitively inhibited by SCN⁻ in the solution matrix. However, adaptation increased the sensitivity of <em>Ap. cupricumulans</em> SCN⁻ and resulted in an inhibition constant (<span><math><msub><mi>K</mi><mi>i</mi></msub></math></span>) ∼2 times smaller relative to the control strain. The presented inhibition model predicted experimental data well, particularly at concentrations between 1 and 1.5 mg/L SCN⁻; at concentrations above 1.5 mg/L SCN the deviation between repeat data sets was exacerbated and reflected an elevated degree of sensitivity to culture conditions and the potential impact of multiple stressors. Adaptation to 1 mg/L SCN⁻ did not confer any beneficial alteration within the cell and highlighted that the accumulation of SCN⁻ within biooxidation circuits should be carefully monitored to maintain the desired structure of the microbial community, and therein process efficiency.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106431"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157544","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":"Reducing silica in zirconium leachate from washed and dried frit powder: Role of cold and concentrated nitric acid and avoidance of crud formation","authors":"Sandeep Singh Tomar ,&nbsp;Garima Pandey ,&nbsp;Nirvik Sen ,&nbsp;Gaurav Varshney ,&nbsp;Sulekha Mukhopadhyay","doi":"10.1016/j.hydromet.2024.106434","DOIUrl":"10.1016/j.hydromet.2024.106434","url":null,"abstract":"<div><div>Traditionally zirconium is leached from washed dried frit (WDF) powder using commercial-grade nitric acid at 80 °C, which results in a leachate containing significant colloidal silica, leading to emulsion and solvent loss. This work used red fuming nitric acid (RFNA) which consists of 84 % nitric acid, 13 % dinitrogen tetroxide and 1–2 % water, as a novel leaching agent. The reduced water content in RFNA enhances the acid strength and prevents colloidal silica formation. This improves zirconium recovery and reduces co-leaching of silica. Optimization efforts focused on operating parameters (impeller speed, temperature, time, acid concentration, liquid-to-solid ratio during reaction and washing steps) to maximize zirconium recovery while minimizing silica in the pregnant leach solution (PLS). Avrami-Erofeev model was used to identify the reaction regime and estimate the apparent rate of leaching. The leaching process was found to follow a complex mechanism. Fourier-transform infrared (FT-IR) spectra of leach residue were analysed to characterize the silica. Zirconium concentration in the PLS from WDF powder dissolved in concentrated nitric acid reached approximately 87 g/L compared to 67 g/L using hot acid leaching (29.8 % increase). Silica concentration decreased from 6500 mg/L to 400 mg/L (93.8 % decrease) using this novel approach, achieving nearly 30 % higher zirconium concentration in the PLS compared to traditional methods.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106434"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157108","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 recovery of rare earth elements from apatite concentrate via pre-leaching, pressure leaching, and precipitation: Process evaluation","authors":"Farid Ahani ,&nbsp;Maryam Osali ,&nbsp;Hamid Khodaei ,&nbsp;Saeid Karimi ,&nbsp;Javad Moghaddam","doi":"10.1016/j.hydromet.2024.106429","DOIUrl":"10.1016/j.hydromet.2024.106429","url":null,"abstract":"<div><div>The depletion of primary resources and the ever-increasing demand for advanced products containing rare earth elements (REEs) have recently attracted significant attention in the processing of low-grade REEs resources. This study proposes a pre-leach stage to extract non-REEs and enrich the REEs in the residue from apatite concentrate (AP) containing 1.28 % REEs. Over 98.9 % calcium and 98.1 % phosphorous were leached in a solution of 2.18 M HNO₃, at 45 °C and a solid/liquid ratio of 10 % (<em>w</em>/<em>v</em>) after 40 min. In the same experiment, the leaching efficiency of REEs was lower than 5 %. The proposed method increased the concentration of REEs in AP from less than 1.28 % to over 7.20 % (<em>w</em>/w). The pressure leaching results of the upgraded REE concentrate in HNO₃, revealed that the increase in HNO₃ concentration, leaching time, and liquid/solid (L/s) ratio have a positive effect on leaching efficiency. Meanwhile, as temperature increases, the leaching efficiency of REEs decreases. The XPS analysis revealed the presence of both Ce(III) and Ce(IV) phases in the leach residue, indicating the oxidation of Ce(III) during the leaching process. Additionally, the XPS spectrum demonstrated that other REEs (<em>i.e.</em>, Nd and La) are present in the pre-leach residue in a trivalent form. Furthermore, thermodynamic calculations of the product resulting from the pre-leaching of AP indicated that Ca²⁺ and H₃PO₄ species are predominant in the solution. Moreover, the key factors determining the re-precipitation of REEs in the pre-leaching stage are two species: H₃PO₄ and Ca[H₂PO₄]⁺. Finally, the leached calcium and phosphorous from the purified leachate were precipitated as a pure hydroxyapatite by adding ammonia. Besides, more than 95 % of REEs were converted to the aqueous phase from pre-leach residue using pressure leaching with HNO₃.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106429"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157545","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":"Quantification and recovery prospects of critical metals and rare earth elements in Victorian brown coal fly ash: A promising secondary source for critical metal extraction","authors":"Bennet Sam Thomas,&nbsp;Sankar Bhattacharya","doi":"10.1016/j.hydromet.2024.106428","DOIUrl":"10.1016/j.hydromet.2024.106428","url":null,"abstract":"<div><div>Coal fly ash (CFA), an anthropogenic waste generated from the combustion of coal, is in research focus for the potential it holds in extracting critical metals. Within the classification of critical metals, includes a group of 16 commercially significant metals known as rare earth elements (REEs). The supply of REEs is touted as one of the building blocks of the 21st century to realize a sustainable future. High demand projections for the future coupled with market monopolization, provide an impetus to extract REEs from secondary resources such as CFA. In this study, three Victorian brown CFA samples were examined, quantifying 41 metals and 16 REEs. All three CFA samples had an outlook coefficient (i.e., ratio of the relative amount of critical REE to the relative amount of excess REE) &gt; 0.7, with an observed light REE enrichment and Eu anomaly, implicating the samples as a suitable feedstock for REE extraction. Quantification studies rendered Loy Yang CFA, <em>from the largest power station in Australia,</em> to be rich with REEs with a total metal concentration of 418 mg/kg, followed by CFA from other power stations (Yallourn: 73.6 mg/kg and Morwell: 36.1 mg/kg). A comparative study for different methods of calibration during inductively coupled plasma - mass spectrometry analysis (and external vs internal calibration), depicted the reproducible nature of results while using an internal standard. Subsequently an in-house developed multi-element standard addition method is proposed, within an accuracy of 2–50 %. A new sequential extraction method for studying modes of occurrences in CFA, depicting REE association with larger fractionation, is explored, with results rendering REE association with: aluminosilicate bound (∼ 61.2 %) &gt; acid soluble fraction (23.1 %) &gt; crystalline Fe bound (5.9 %) &gt; organic matter bound (5.3 %) &gt; amorphous Fe bound (3.5 % TREE) &gt; Mn-oxide bound (0.9 % TREE) &gt; water soluble mineral bound (0.1 % TREE). This underpins the strong REE association in the residual and acid soluble fraction in brown CFA.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"232 ","pages":"Article 106428"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157541","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}