Hydrometallurgy最新文献

{"title":"Fundamentals of copper(II) adsorption on phyllosilicate minerals relevant to crud formation in solvent extraction from heap leach liquors","authors":"J. Valenzuela-Elgueta ,&nbsp;A.V. Delgado ,&nbsp;S. Ahualli","doi":"10.1016/j.hydromet.2024.106409","DOIUrl":"10.1016/j.hydromet.2024.106409","url":null,"abstract":"<div><div>Because of the common presence of different silicate minerals, like kaolinite, montmorillonite and muscovite as gangue minerals in the beneficiation of copper oxide ores, the interaction between copper(II) ions in solution and each of these minerals is a field of strong interest, considering their implications on the aggregation of these minerals in the extreme pH conditions typical of hydrometallurgical unit operations for copper production. After copper adsorption isotherms determination at pH 2 and 4, specific adsorption data were fitted to both Langmuir and Freundlich models. It was found that adsorption is systematically larger at pH 4, and that montmorillonite is the mineral that displays a larger adsorption capacity, as in principle expected by its larger cation exchange capacity, CEC. A good fitting to the Langmuir model was obtained for the three samples, and montmorillonite also appears to conform to Freundlich isotherm predictions, as the tested concentrations of copper(II) do not allow to reach saturation. Furthermore, some desorption is measured for kaolinite and muscovite at the highest copper concentrations, probably because of significant interactions between the adsorbed ions. No such desorption was detected in montmorillonite samples. An XPS analysis of the surfaces of the three minerals suggests that copper adsorption in kaolinite is not associated to a cation exchange process but rather to electrostatic interactions between silica-like faces of the clay. In contrast, ionic exchange of structural calcium (for montmorillonite) or potassium (in the case of muscovite) seems to be the predominant mechanism of Cu(II) adsorption in the other two samples. Electrophoretic mobility determinations agree with this hypothesis: the mobility (always negative, with no traces of charge inversion) decreases in absolute value when kaolinite particles are in contact with solutions of increasing copper concentration at pH 2 or pH 4. On the other hand, the electrophoretic mobility values of muscovite and montmorillonite showed a weak pH and copper concentration dependence, a result that matches well with the ion exchange processes detected in the XPS measurements.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106409"},"PeriodicalIF":4.8,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Separation of hafnium from zircon leach solution using anion-exchange resin and production of high-purity zirconia for nuclear applications","authors":"Z.H. Ismail,&nbsp;S.E. Rizk,&nbsp;E.M. Abu Elgoud,&nbsp;H.F. Aly","doi":"10.1016/j.hydromet.2024.106411","DOIUrl":"10.1016/j.hydromet.2024.106411","url":null,"abstract":"<div><div>The ion exchange process using an anion exchange resin (Bio-Rex 5) was employed with batch and column techniques to isolate nuclear-grade zirconium/hafnium from a leach solution of zircon ore. Batch studies were conducted to optimize the conditions for sorption and desorption of Zr(IV) and Hf(IV). The highest separation factor of 10.3 was achieved under equilibrium conditions of 11.0 mol/L HCl, contact time of 30.0 min, solution volume-to-mass of resin ratio of 0.10, and 15 °C. The sorption process for both metals obeyed a pseudo-second-order model and the experimental sorption data was well-described by both Langmuir and Freundlich models. The maximum sorption capacities were determined to be 46.2 mg/g for Zr(IV) and 37.8 mg/g for Hf(IV). The Zr(IV) and Hf(IV) ions were effectively desorbed by 0.1 mol/L nitric and 2.0 mol/L hydrochloric acid solutions, respectively, with total yields of 89.7 % Zr(IV) and 85.8 % Hf(IV) via multistage desorption processes. In both batch and column techniques, the resin exhibited sorption selectivity for Zr and Hf over interfering elements in the hydrochloric acid leach solution of zircon sand. The loaded resin from real leach solution was subjected to desorption, zirconium sulfate precipitation, and calcination at 650  °C, resulting in a pure zirconia powder suitable for nuclear applications. This technique presents a promising effective method for the selective separation and recovery of high-purity zirconium and hafnium from their natural sources.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106411"},"PeriodicalIF":4.8,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement of gold extraction by citric acid-assisted microwave roasting of Carlin-type gold ores and sulfide/thiosulfate leaching","authors":"Tiantian Wu ,&nbsp;Zhihui Shen ,&nbsp;Zhenwu Shi ,&nbsp;Jianlong Wang ,&nbsp;Yueqin Qiu ,&nbsp;Song Mao","doi":"10.1016/j.hydromet.2024.106410","DOIUrl":"10.1016/j.hydromet.2024.106410","url":null,"abstract":"<div><div>The occurrence of most gold in an encapsulated state often results in poor extraction efficiency, and efficient pretreatment is the key to effective gold recovery from Carlin-type gold ores. This study investigated the enhancement of citric acid (CA) assisted microwave (MW) roasting on gold extraction from Carlin-type gold ores by sulfide/thiosulfate leaching, primarily analyzing in-situ phase transformation, microstructure characterization, and the thermal decomposition behavior of solids. The results show that gold extraction increases significantly with increasing CA dosage, furnace temperature, and roasting time when heated by MW, reaching a maximum of 87.7% at a CA dosage of 2% and a temperature of 500°C for 60 min in the presence of air. Moreover, extraction is significantly higher with CA than without CA at roasting temperatures below 300°C. The phase transition of gold-bearing pyrite is controlled mainly by temperature when heated by MW without CA, resulting in surface oxidation at 300°C, with significant oxidation at 400°C, and complete transformation into Fe₂O₃ and SO₂ at temperatures over 500°C. Interestingly, CA and its decomposition products of CO₂ and H₂O induce the generation of unstable intermediates at 100°C, such as FeCO₃, FeC₂₁H₂₁O₇, and FeOOH. The decomposition of these intermediates at higher temperatures results in the rapid formation of a hematite layer with developed pores at 300°C, which provides more diffusion channels for SO₂ and O₂, producing coral-like porous hematite particles. Both number of pores and the pore size are larger at 500°C. The combined effect of MW and CA enhances exposed gold content over 70% which in turn increases gold extraction. This work provides significant insights into the enhancement process of gold extraction of CA-assisted MW roasting.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106410"},"PeriodicalIF":4.8,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433066","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 organic phase from crud in solvent extraction unit of Sarcheshmeh copper complex in Iran by powerful water-absorbent reagents","authors":"Mohammad Anary-Abbasinejad ,&nbsp;Zahra Manafi ,&nbsp;Fatemeh Zamani ,&nbsp;Parisa Salarizadeh ,&nbsp;Mehri Shahhoseini ,&nbsp;Fereshteh Vahedi ,&nbsp;Seyed Ali Seyedbagheri","doi":"10.1016/j.hydromet.2024.106408","DOIUrl":"10.1016/j.hydromet.2024.106408","url":null,"abstract":"<div><div>The formation of stable multi-phase emulsions (crud) is a serious problem in almost all commercial solvent extraction (SX) plants. Crud is a mixture of organic and aqueous phases, air, and organic or inorganic solid particles, often found to distribute itself randomly throughout the separating phases of SX plants. Crud formation is encountered in almost all SX units in metal extraction plants. It causes the loss of solvent and thus increases the process costs. Therefore, the removal of crud and recovery of the expensive organic phase including diluent and extracting reagents from it is of great importance. In this research, the applicability of a range of powerful water absorbent reagents was studied for the recovery of organic phase from the crud formed in copper extraction/electrowining unit of Sarchashmeh copper complex (IRAN). The reagents included gypsum, carbomer, sodium polyacrylate, sodium sulfate, magnesium sulfate and calcium chloride. The results showed that gypsum, carbomer and sodium polyacrylate are effective additives which let the organic phase to be recovered with up to 95 % yield. To ensure that gypsum does not cause a negative effect on the copper loading and stripping of the recovered solvent, the extraction/stripping properties of the organic phase separated with gypsum was compared with the organic phase separated by centrifugation without additives. Surface tension analysis of the gypsum-recovered organic phase also confirmed its suitability for recovery of organic phase from crud. Finally, the calcium content of gypsum-recovered organic phase was measured and compared with that of the organic phase separated by centrifugation without any additive.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106408"},"PeriodicalIF":4.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421641","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 combined leaching of copper, gold and uranium in chloride solutions. II. Concentrate leach tests","authors":"M. Nicol ,&nbsp;K. Ye ,&nbsp;N. Garrard","doi":"10.1016/j.hydromet.2024.106407","DOIUrl":"10.1016/j.hydromet.2024.106407","url":null,"abstract":"<div><div>This study of the simultaneous leaching of copper, gold and uranium from a flotation concentrate is aimed at establishing the conditions that could be applied in a possible heap leach process that would recover all three metals (plus silver, if present) in a single step. The results obtained in this study confirm the results obtained in Part I (Nicol et al., 2024) that enhanced rates for leaching of chalcopyrite from flotation concentrates from two different sources can be obtained in acidic chloride solutions in the presence of chlorate ions. The measurements of the solution potentials during leaching with chlorate are similar to those obtained previously and confirm that chlorine generated by the chlorate-chloride reaction is the active oxidant.</div><div>Uranium is dissolved even in the absence of chlorate by iron(III) as the oxidant. The latter is re-generated by reaction of iron(II) with chlorate. The dissolution of gold requires higher potentials, and it is only leached when the potential approaches 1.0 V in concentrated chloride solutions. At low chloride concentrations (1 M), gold is not dissolved because of apparent passivation.</div><div>An electrochemical study of the behaviour of gold in chloride solutions in the presence of sulfide ions has shown that the passivation is probably the result of the formation of a layer of Au₂S on the gold surface at low potentials before the addition of chlorate to the leach solutions i.e., before the generation of sufficient chlorine concentrations. At potentials above about 0.95 V Au₂S is unstable being oxidised to AuCl₂⁻ and elemental sulfur thereby eliminating passivation.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106407"},"PeriodicalIF":4.8,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421713","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":"The combined leaching of copper, gold and uranium in chloride solutions. I. Chalcopyrite","authors":"M. Nicol ,&nbsp;K. Ye ,&nbsp;N. Garrard","doi":"10.1016/j.hydromet.2024.106406","DOIUrl":"10.1016/j.hydromet.2024.106406","url":null,"abstract":"<div><div>In a study (Part II) aimed at the simultaneous heap leaching of copper (predominantly chalcopyrite), gold and uranium from an ore, it was found that this could be achieved using chlorate as the oxidant in chloride solutions. As a result, a more detailed study has been made using electrochemical and batch leach tests on pure chalcopyrite electrodes under typical heap leach conditions.</div><div>The use of chlorate at moderately low concentrations has shown that enhanced rates of dissolution of chalcopyrite can be maintained over periods up to 4 days at ambient temperatures in acidic chloride solutions. The rate of dissolution is enhanced at higher acid concentrations. The rate in the presence of chlorate does not appear to depend on the iron(III) (and presumably the copper(II)) concentration.</div><div>The observed rates are significantly greater than those predicted for oxidative dissolution from the electrochemistry and the mixed potential model. An alternative non-oxidative mechanism has been revisited to account for this difference.</div><div>A preliminary measurement has been made of the kinetics of the oxidation of hydrogen sufide and iron(III) by low concentrations of chlorine produced by reaction of chlorate with chloride ions. These reactions are rapid, and theory shows that they would support the proposed non-oxidative mechanism.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106406"},"PeriodicalIF":4.8,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421715","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":"Scaling analysis of electrodeposited copper and the influence of a modified polysaccharide on surface roughness","authors":"Jeffrey L. Shepherd ,&nbsp;Karl Torman ,&nbsp;Michael S. Moats ,&nbsp;Joseph Bauer ,&nbsp;Eduard Guerra","doi":"10.1016/j.hydromet.2024.106405","DOIUrl":"10.1016/j.hydromet.2024.106405","url":null,"abstract":"<div><div>The influence of a commercially available modified polysaccharide (HydroStar®, Chemstar Chemical Products) on the roughness of short-term and small-scale copper electrodeposits was investigated using Atomic Force Microscopy (AFM), linear scan profilometry and scaling analysis. Copper was deposited on a 316L stainless steel cathode at 40 °C and 300 A m⁻² from an electrolyte containing 40 g L⁻¹ Cu²⁺, 170 g L⁻¹ H₂SO₄, 1.5 g L⁻¹ Fe³⁺, 15 mg L⁻¹ Cl⁻ and either 0, 10, 50 or 100 mg L⁻¹ of HydroStar. Copper deposits produced between 15 and 25 min were imaged using AFM and 2D linear scan profilometry was used to gather surface features of copper samples produced in the range of 120 and 240 min. Scaling analysis was applied to quantify the surface characteristics of limiting roughness (δ) and critical length (L_C) from which δ/L_C was computed and related to the aspect ratio of surface features. All copper deposits showed a general rise in δ and L_C with deposition time but the growth rates decreased when HydroStar was included in the electrolyte indicating that the additive lowers the vertical height of surface features as well as their widths. Furthermore, copper deposits were more consistently produced in the presence of HydroStar and, for a given value of limiting roughness, had surface features with wider base than those created in the absence of the additive. The results show that the modified polysaccharide acts to create smooth copper deposits by generating surface features with lower aspect ratios.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106405"},"PeriodicalIF":4.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421714","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 V2O5 using Pb5(VO4)3OH recovered from Bayer vanadium sludge through H2SO4 pre-treatment, H2O2 leaching, V5O12∙6H2O and V10O24∙12H2O precipitation and oxidative roasting at 400 °C","authors":"Changda Zhang,&nbsp;Qiusheng Zhou,&nbsp;Yilin Wang,&nbsp;Leiting Shen,&nbsp;Guihua Liu,&nbsp;Tiangui Qi,&nbsp;Zhihong Peng,&nbsp;Xiaobin Li","doi":"10.1016/j.hydromet.2024.106404","DOIUrl":"10.1016/j.hydromet.2024.106404","url":null,"abstract":"<div><div>Bayer vanadium sludge (BVS), discharged during the Bayer alumina production, is a promising secondary resource for the supply of vanadium. Previous vanadium extraction process involving Pb₅(VO₄)₃OH precipitation by PbSO₄, H₂SO₄ and (NH₄)₂SO₃ leaching, (NH₄)₂S₂O₈ oxidation followed by ammonium vanadate precipitation, suffered from large amounts of reagent consumption and discharge of ammonia-containing waste. In this study, a cleaner and cost-efficient process based on H₂SO₄ pre-treatment, H₂O₂ leaching, hydrolytic precipitation, and preparation of V₂O₅ through oxidative roasting was proposed to reduce reagent consumption and waste. Results show that the maximum vanadium leaching efficiency reached 99.7 % under the most suitable conditions of H₂SO₄ pre-treatment with H₂SO₄/Pb₅(VO₄)₃OH molar ratio of 6.5, pulp density of 250 g/L at 90 °C for 4 h followed by H₂O₂ leaching with H₂O₂/V molar ratio of 3.0 at 15 °C for 10 min. Furthermore, 96.5 % of vanadium was precipitated in the forms of V₅O₁₂∙6H₂O and V₁₀O₂₄∙12H₂O by heating the leach liquors to 100 °C for 60 min, followed by the oxidative roasting at 400 °C for 2 h to prepare V₂O₅ product with a purity of 99.2 %, with only H₂O as a by-product. This research provides new insights into vanadium extraction in a cleaner, cost-efficient, and sustainable industrial process which saves 147.4 $/t Pb₅(VO₄)₃OH.</div></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106404"},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311039","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":"Solvent extraction of titanium(IV) from orthophosphoric acid media using Aliquat-336/kerosene and stripping with nitric acid","authors":"Ahmed A. Galhoum,&nbsp;Basma T. Mohamed,&nbsp;Shaimaa S. Abdulmoteleb,&nbsp;Said I. Mohamady,&nbsp;Nagwa I. Falila","doi":"10.1016/j.hydromet.2024.106403","DOIUrl":"10.1016/j.hydromet.2024.106403","url":null,"abstract":"<div><p>Titanium extraction from acidic solutions was investigated using Aliquat-336, considering factors like acid type and concentration for leaching, diluent type for solvent extraction, equilibration time, extractant concentration, phase ratio, and temperature. Kerosene exhibited superior performance as an aliphatic diluent for Aliquat-336 compared to other utilized diluents. The extraction efficiency was inversely proportional to the dielectric constant of the diluents. The quantitative Ti(IV) extraction efficiency from phosphoric acid (6 M H₃PO₄) leach liquor of ilmenite and rutile achived 98 % at room temperature (298 K) in 10 min after mixing with 0.1 M Aliquat-336 dissolved in kerosene at a phase volume ratio of 1:1 (Aq:Org). The exothermic extraction process occurred spontaneously. The proposed extraction mechanism using Aliquat-336/kerosene involves ion-pair association of the extractant with a Ti(IV) complex, confirmed by FTIR spectroscopy. The Ti(IV) ions were effectively stripped using HNO₃ (3 M) with an aqueous:organic phase volume ratio of 1:1 at 25 °C after a contact time of 10 min in each step. The Aliquat-336/kerosene efficiently tested for Ti(IV) recovery from acidic Abu-Ghalaga ilmenite and rutile leachate. The findings indicate that, the phosphate medium is highly efficient in extracting Ti(IV), even with low concentration of Aliquat-336 in kerosene, especially in comparison to the impurities such as Fe, Cr, and Al. The EDX, XRD, and wet chemical analyses of the final product after the hydrolysis of stripped Ti(IV) from samples originating from the Abu-Ghalaga area and rutile samples, confirmed the formation of high-purity TiO₂ (predominantly anatase phase). The SEM results showed particles with a regularly spherical structure and uniform size.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106403"},"PeriodicalIF":4.8,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142244150","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 extraction of silver from jarosite residues produced in the zinc hydrometallurgical process using thiourea under acidic conditions: Kinetic analysis and leaching optimization","authors":"Mary C. Nolasco ,&nbsp;Israel Rodríguez ,&nbsp;Javier E. Vilasó ,&nbsp;Mizraim U. Flores ,&nbsp;Thangarasu Pandiyan ,&nbsp;Emmanuel J. Gutiérrez ,&nbsp;Javier Aguilar ,&nbsp;Martín Reyes ,&nbsp;Iván A. Reyes","doi":"10.1016/j.hydromet.2024.106396","DOIUrl":"10.1016/j.hydromet.2024.106396","url":null,"abstract":"<div><p>In this work, an industrial hazardous jarosite residue produced in the zinc hydrometallurgical process containing silver was used to evaluate the feasibility of using thiourea (Tu) for silver leaching under acidic conditions in the presence of oxalate (C₂O₄²⁻ ion denoted as Ox²⁻). The shrinking core kinetic model (SCKM) was applied to evaluate the effect of variables on the reaction rate. The chemical reaction of H₃O⁺ with the jarosite surface was the controlling stage. The results of batch experiments revealed that silver extraction is influenced by various factors in the descending order: pH &gt; T (temperature) &gt; [Tu] (thiourea concentration) &gt; [Ox²⁻] (oxalate concentration). The extraction efficiency of Ag was 98 % at high levels of both T and [H₂SO₄], although a higher [Tu] was required. High Tu consumption was associated with the stability of Tu due to the presence of Fe³⁺ and Cu²⁺ ions leached along with Ag⁺, which affect the redox potential catalyzing Tu oxidation. Temperature is the most effective variable with a reaction rate constant of k_exp = 1.1 min⁻¹ at 60 °C, but it causes a decrease in silver extraction to 92.5 %. The kinetic parameters were obtained using the SCKM; furthermore, the experimental results were statistically validated through a surface response experimental design.</p></div>","PeriodicalId":13193,"journal":{"name":"Hydrometallurgy","volume":"231 ","pages":"Article 106396"},"PeriodicalIF":4.8,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162160","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}