MINERALS ENGINEERING
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2024
·
IF 4.9
Guowei Zhang,Lei Hou,Peng Chen,Qi Zhang,Yu Chen,Nasriddinov Zamoniddin Zainiddinovich,Chunhui Wu,López Valdivieso Alejandro,Feifei Jia
Gold thiosulfate leaching is renowned for its non-toxic and high leaching efficiency. However, in traditional thiosulfate leaching systems, the presence of a high mixed potential and oxidizing metal ions in the solution environment leads to the consumption of thiosulfate through oxidation and causes passivation of the gold surface. Here, we proposed a novel thiosulfate leaching system mainly using non-toxic copper-ethydiaminedhephen acetic (EDDHA) replacing the conventional copper-ammonia. In this system, the gold leaching process mainly catalyzed by the stable Cu-EDDHA complex ion (as oxidizing agent analyzed by UV–vis spectrophotometer). The complexation of Cu(II) attributed to EDDHA reduces the mixed potential in the leaching process. The coordination also prevents the oxidation of thiosulfate by free copper ions. Accordingly, thiosulfate consumption during leaching is minimized, as it mitigates oxidation and self-decomposition. Besides, Raman and XPS spectrum demonstrate that introduce of EDDHA into the thiosulfate system can effectively eliminate the harmful surface passivation of gold, which enhance the gold leaching efficiency. In addition, by fulfilling a set of conditions, a gold extraction of 82.84 % can be attained in new system compared with 56.02 % for conventional cyanide leaching. Further, adding EDDHA to the thiosulfate leach reduced the reagent consumption from 103.19 kg/t to 10.54 kg/t. The results are benefits to the development and utilization of thiosulfate gold leaching.
研究领域:
冶金化学
·
环境科学
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产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2019
·
IF 3.315
Zaizheng Dong,Yimin Zhu,Yuexin Han,Xiaotian Gu,Kai Jiang
Pyrite, usually associated with gold deposit, is disadvantageous to gold leaching. In this study, an environmentally friendly oxidizing agent, chlorine dioxide (ClO 2 ), was used for the first time to efficiently oxidize pyrite under mild experimental conditions, so as to remove the adverse effects of pyrite on gold leaching. Firstly, with established content determination method, the prepared pure ClO 2 solutions with different concentrations were investigated on their impacts on pyrite oxidation efficiency. Secondly, solid NaClO 2 was used to oxidize pyrite under acidic condition, providing a new oxidation approach for practical application. In fact, the key of the approach is the use of solid NaClO 2 in acidic environment to generate ClO 2 and then oxidize pyrite. For the pyrite pulp with 400 mL volume with an initial concentration of 0.025 M, the oxidation efficiencies of Fe and S in pyrite reached 99.8% and 98% at a NaClO 2 concentration of 0.125 M and C 4 H 6 O 6 concentration of 0.0025 M with magnetic stirring for 1 h at 30 °C in a constant temperature water bath. The addition of C 4 H 6 O 6 can increase the acidity of the system and form a complex with iron ions, thereby preventing the precipitation of ferrihydrite from acidity changes caused by overdose NaClO 2 . After redox reaction, the acidity and oxidation–reduction potential (ORP, E h ) of the system were noticeably increased. The results of chemical composition analysis and X ray diffraction (XRD) analysis of pyrite oxidation residue confirmed that pyrite was oxidized to ions by ClO 2 , and no solid by-products such as Fe 2 O 3 or Fe(OH) 3 were formed. The scanning electron microscope (SEM) analysis of residual pyrite indicated that small pyrite particles were oxidized first, and then oxidants eroded the defects of large particles, gradually oxidizing all pyrites. This method is expected to be used as a pretreatment approach for pyrite oxidation before gold leaching process.
研究领域:
矿物学
·
环境科学
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产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2019
·
IF 3.315
Zaizheng Dong,Yimin Zhu,Yuexin Han,Peng Gao,Xiaotian Gu,Yongsheng Sun
Arsenopyrite is a typical arsenic-containing mineral, and gold is generally hosted by arsenopyrite mineral which adversely affects gold leaching. In this study, a novel environmentally friendly oxidant, chlorine dioxide (ClO 2 ), was used for the first time to efficiently oxidize arsenopyrite under acidic conditions, preventing the adverse effect of arsenopyrite on gold leaching. The addition of solid NaClO 2 to acidic arsenopyrite slurry made the oxidation of arsenopyrite feasible for practical purposes, as NaClO 2 generates ClO 2 under acidic conditions, which then oxidizes arsenopyrite. For a 400 mL sample of arsenopyrite pulp with the initial concentration of 4.07 g/L (0.025 M), the oxidation efficiencies of Fe and As in arsenopyrite reached 94.25% and 85.39%, respectively for NaClO 2 and H 2 SO 4 concentrations of 0.125 M each, under magnetic stirring for 1 h at 30 °C in a constant-temperature water bath. At the end of the reaction, both the acidity and oxidation-reduction potential of the system increased, and the ClO 2 concentration correspondingly decreased. Chemical composition analysis, X-ray diffraction analysis, particle size distribution measurements, scanning electron microscopy combined with energy dispersive spectrometer analysis, and X-ray photoelectron spectroscopy of arsenopyrite mineral ore and its oxidized residues were performed under different reaction conditions. Analysis results indicated that tiny amorphous precipitates of the oxidation by-products, such as FeAsO 4 ·7H 2 O, H 3 AsO 3 , Fe 2 (SO 4 ) 3 ·7H 2 O, and hydrated ferric oxides would cover the surface of unreacted arsenopyrite at low H 2 SO 4 concentration, which prevented the oxidation-reduction reaction from proceeding. As the concentrations of H 2 SO 4 and NaClO 2 increased, fine arsenopyrite particles were oxidized first, and ClO 2 gradually eroded the surface of the unreacted arsenopyrite minerals to form cracks, defects, and pores, until arsenopyrite was fully oxidized. ClO 2 presents several advantages: it can be easily prepared, it is a strong oxidant, and is non-polluting. Therefore, the procedure in this study is expected to be used as a novel method for preventing the effect of arsenopyrite enwrapping gold in refractory gold ores and for directly leaching gold.
研究领域:
化学工程
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环境科学
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冶金学
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DOI
高影响因子
JOM
·
2019
·Vol. 71
·期 10
·3673-3681
·
IF 2.305
Gao Guilan,He Xin,Lou Xiaoyi,Jiao Zheng,Guo Yaoguang,Chen Shuai,Luo Xingmin,Sun Suyang,Guan Jie,Yuan Hao
Recycling of valuable metals from spent lithium-ion batteries (LIBs) appears inevitable for both environmental protection and resource recovery. In the present study, an efficient hydrometallurgical leaching of Co and Li from cathode materials of spent LIBs using a citric acid/sodium thiosulfate (Na 2 S 2 O 3 ) system is explored. The effects of citric acid and Na 2 S 2 O 3 concentrations, leaching time, temperature, and the solid/liquid ( S / L ) ratio on the leaching processes are also examined. With the exception of the S / L ratio, the increase of citric acid concentration, Na 2 S 2 O 3 concentration, leaching time, and temperature all have positive effects on the leaching of Co and Li. Ultimately, approximately 96% of Co and 99% of Li are recycled from the spent LIBs in this citric acid/sodium thiosulfate system under the leaching conditions of an S / L ratio of 20 g l −1 , concentration of Na 2 S 2 O 3 of 0.3 M, concentration of citric acid of 1.2 M, leaching time of 30 min, and leaching temperature of 70°C. The Avrami equation is well fitted by the data of the leaching processes, and model equations are built to describe the leaching of Co and Li. Furthermore, pure sulfur can be obtained as a by-product during the leaching process, and SO 2 produced during the reaction is easily collected as a raw material for industrial production of sulfuric acid. The present study represents a promising process for hydrometallurgical recovery of valuable metals from spent LIBs.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 4
·835-850
·
IF 7.2
Li Jinlin,Sun Chunbao,Kou Jue,Wang Peilong,Liu Xinyu
Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety hazards during transportation and use. Therefore, it is necessary to develop gold leaching reagents that can replace cyanide. This paper introduces a method for synthesizing a gold leaching reagent. Sodium cyanate is used as the main raw material, with sodium hydroxide and sodium ferrocyanide used as additives. The gold leaching reagent can be obtained under the conditions of a mass ratio of sodium cyanate, sodium hydroxide, and sodium ferrocyanide of 15:3:1, synthesis temperature of 600°C, and synthesis time of 1 h. This reagent has a good recovery effect on gold concentrate and gold-containing electronic waste. The gold leaching rate of roasted desulfurized gold concentrate can reach 87.56%. For the extraction experiments of three types of gold-containing electronic waste, the gold leaching rate can reach over 90% after 2 h. Furthermore, the reagent exhibits good selectivity towards gold. Component analysis indicates that the effective component in the reagent could be sodium isocyanate.
研究领域:
冶金化学
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环境科学
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材料科学
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DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Zhihui Shen,Tiantian Wu,Jianlong Wang,Song Mao,Xianchen Wang
Efficient pretreatment of fine-disseminated gold ore is a challenge in effective gold extraction due to the invisible occurrence of the most encapsulated gold. In this study, we investigated the mechanism of co-pretreatment with eco-friendly CaO and Na 2 CO 3 to improve gold extraction from fine-disseminated gold ore using element content and valence measurement, phase composition analysis, micromorphology and structure characterization, and thermodynamic calculation . The results indicated that more than 75% of gold was encapsulated in pyrite, quartz and calcite . The gold leaching rate evidently increased with the reagent content and slurry temperature of the pretreatment , reaching a maximum of 86.55% at 60 °C and CaO and Na 2 CO 3 concentrations of 16 and 32 g/L, respectively. At lower concentrations of OH − or CO 3 2− , pyrite oxidation and quartz corrosion were both limited. Interestingly, at higher concentrations of OH − and CO 3 2− , pyrite was ultimately converted to Fe 2 O 3 and SO 4 2− under aerobic conditions ; meanwhile, partial dissolution products of quartz reacted with the intermediates of pyrite oxidation, generating a new phase of Fe 2 SiO 4 . In addition, the soluble intermediate ferric carbonate complexes, formed by the induction of sufficient CO 3 2− , inhibited the accumulation of the passivation layer on the pyrite surface, resulting in constant oxidation of pyrite. Furthermore, the oxidation of pyrite was the maximum at 60 °C, but limited at 90 °C due to the hindrance of oxidation product coating. As a result, the phase transition of gold-bearing pyrite and quartz could be enhanced by the synergistic pretreatment of CaO and Na 2 CO 3 , resulting in an approximately 30% increase in both exposed gold content and gold leaching rate. This research proposes a promising green pretreatment with cost benefits for fine-disseminated gold ore and provides significant insights into phase transition regulation to improve gold leaching.
研究领域:
矿物加工工程
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冶金学
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环境科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Qihao Gui,Libo Zhang,Shixing Wang,Jianjun Fang,Zixing Song,Zhicong Wei,Dianwen Liu
Pyrite enclosure poses a significant challenge in refractory gold ore processing, inhibiting gold leaching. This study explores Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs) as an effective alternative for pretreating such ores. The oxidation pretreatments were performed under heat and ultrasound activation methods, including heat and ultrasound, and the influences of pretreatment time, pH, ultrasound power, pretreatment temperature, and precursor (PDS) concentration were investigated. Both ultrasonic and heat activation effectively mitigate the negative impact of pyrite enclosure on gold leaching. Specifically, the gold leaching rate improved from 21.9 % to 46.1 % and 74.9 % with heat and ultrasound activation, respectively The and generated by PDS dominate the pyrite oxidation according to EPR and quenching tests. Meanwhile, the SR-AOPs treatment also promotes the interactions between pyrite enclosure and leaching agent, reducing the negative influences of pyrite. Kinetic studies indicated that the oxidation processes are different under heat and ultrasound activation. Heat activation is governed by an interfacial chemical reaction, with an activation energy of 25.57 kJ/mol. In contrast, ultrasound-induced cavitation and microjets remove the oxidation layer, disrupt the pyrite crystal structure, and expose encapsulated gold. These effects accelerate pyrite oxidation, shifting the kinetic control step from interfacial chemical reaction to internal diffusion, with a reduced activation energy of 35.06 kJ/mol.
研究领域:
矿物加工工程
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Rong Mu,Zepeng Lv,Shaolong Li,Jilin He,Jianxun Song
Spent SCR catalysts, classified as high-risk solid waste, are produced in large quantities and are rich in critical metals such as Ti, V, W, and Mo, making them highly valuable for recycling. This study proposes a novel process combining hydrogen-rich reduction with hydrometallurgical leaching for the recycling of spent SCR catalysts. Thermodynamic calculations and experimental validation showed that the proposed process converts high-value oxides (TiO 2 , V 2 O 5 , WO 3 and MoO 3 ) into multicomponent carbides under a CH 4 –H 2 atmosphere. The effects of temperature, reaction time, and Fe 2 O 3 additives on phase transformation were systematically investigated. To remove residual impurities that were not reduced in the high-temperature reaction, selective acid and alkaline leaching were employed. Owing to their chemical stability, the formed multicomponent carbides remained inert during leaching. The optimized recycling process involved the addition of 8 wt% Fe 2 O 3 to the catalyst, followed by thermal treatment at 1400 °C for 3 h. Impurities were removed using 0.5 mol·L⁻¹ HCl and 1 mol·L⁻¹ NaOH solutions. The final product exhibited a face-centered cubic structure with a uniform distribution of Ti, V, W, and Mo and an average lattice parameter of 4.3012 Å, as revealed through Rietveld refinement. Impurities such as Fe, Al, Si, Ca, and S were effectively removed. The product can be used in fields such as conductive materials and hard alloys. This study provides a promising route for the high-value utilization of spent SCR catalysts.
研究领域:
环境工程
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冶金学
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材料科学
·
化学工程
·
废弃物回收
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）