Articles de revues : « Zinc leaching »

1

Yang, Jinlin, Xingnan Huo, Zongyu Li et Shaojian Ma. « Study on Hydrometallurgical Treatment of Oxide Ores Bearing Zinc ». Minerals 12, n^o 10 (7 octobre 2022) : 1264. http://dx.doi.org/10.3390/min12101264.

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As the depletion of zinc sulfide ores becomes more severe, investigations into the recovery of zinc from zinc oxide ores have aroused more interest. In this regard, acid-based hydrometallurgical treatment strategies have had great effectiveness. However, they are inadequate for low-grade zinc oxide ores. In this study, we examined the alkaline treatment of gossan for the recovery of oxide ores that bear zinc, such as siderite and limonite. Additionally, of particular note, the effects of a leaching agent, its concentration and time, temperature, liquid-to-solid ratio, as well as the agitation rate on the leaching of zinc from gossan were studied to evaluate the effects of these parameters on the kinetics of zinc dissolution. The results showed that the leaching of zinc is controlled by a single rate-controlling step with an activation energy of 4.458 kJ/mol before 120 min and 5.536 kJ/mol after 120 min, with zinc leaching efficiency less than 50% in all leachings.

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Zhang, Ya Li, Xian Jin Yu, Xiao Na Guo et Xiao Bin Li. « Recovery Technology of Zinc from Hydrometallurgical Zinc Residues ». Advanced Materials Research 396-398 (novembre 2011) : 620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.620.

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In this work, it was aimed to select and propose a feasible as well as an applicable method, or series of methods for the extraction of zinc. After determination of the components of the residue, water leaching, acid leaching and roasting-leaching were performed to reclaim Zn. Roasting-leaching was found to be effectively for Zn extraction by controlling acid mass, roasting duration and temperature as parameters. At the optimum conditions, 0.7 times the amount of H2SO4 at 250 °C for 150 min in roasting, 82.05% of initial Zn content was extracted.

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Ma, Shao Jian, Gui Fang Wang, Jin Lin Yang, Shao Juan Que, Li Qun Tang et Jin Peng Feng. « Study on Preparation Process of Zinc Ferrite ». Advanced Materials Research 201-203 (février 2011) : 1736–40. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.1736.

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Zinc ferrite is usually formed during the roasting of zinc sulfide concentrate with high content of iron and reduces zinc recovery during the leaching of zinc calcine. Because it is difficult to find pure zinc ferrite in nature ore resources or in chemicals market, which impedes the investigation of the reaction characteristics of zinc ferrite and the seek of new technologies for zinc ferrite dissolution, so it is of significance to obtain relatively pure zinc ferrite for further research on zinc calcine leaching. This article investigated the preparation process of zinc ferrite based on the dissolution characteristics of a zinc calcine with 19.38% iron and put forward a method to judge the reaction end point during the leaching of zinc calcine to produce zinc ferrite. The results show that the product of zinc ferrite could be prepared through recovering the leaching residue during leaching the zinc calcine under the initial H2SO4 concentration equal to or larger than 160g/L, and that the leaching end point can be judged by comparing the experimental curve of Zn leaching with the zinc theoretical dissolvability curve.

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Li, Hui, Yutian Fu, Jinglong Liang, Le Wang, Hongyan Yan et Linfei Zhao. « Preparation of Zinc Oxide and Zinc Ferrite from Zinc Hypoxide by Wet Process and Electrochemistry ». Crystals 11, n^o 9 (18 septembre 2021) : 1133. http://dx.doi.org/10.3390/cryst11091133.

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With the increase of zinc resource consumption, the recovery and utilization of zinc resources in zinc suboxide has become one of the current research hotspots. In this study, the electrochemical method was used to remove the impurities in the zinc leaching night and enrich the zinc ferrite in the ammonia leaching residue for the solution and ammonia leaching slag after the ammonia leaching of zinc hypoxide, in order to realize the comprehensive utilization of the essence of zinc immersion night and new resources. The results showed that the reduction potentials of copper, lead, cadmium, and zinc in the ammonia leaching solution were analyzed by electrochemical testing methods to be −0.76 V, −0.82 V, −0.94 V, and −1.3 V, respectively. Through constant potential electrodeposition, the removal rate of copper, lead, cadmium. The removal rate of cadmium is 98.73%, and the removal rate of lead and copper is more than 99%. The purified ammonia leaching solution is evaporated at 90 °C for 25 min to obtain basic zinc carbonate. The purity of ZnO obtained after calcination at 500 °C for 120 min is 96.31%. The ammonia leaching residue was pickled with 3 mol·L−1 acetic acid for 30 min to effectively remove PbCO3, and then magnetic separation was carried out with a current intensity of 1.4 A. The final zinc ferrite content was 83.83%.

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Wang, Jingxiu, Zhe Wang, Zhongzhi Zhang et Guangqing Zhang. « Comparison of Butyric Acid Leaching Behaviors of Zinc from Three Basic Oxygen Steelmaking Filter Cakes ». Metals 9, n^o 4 (7 avril 2019) : 417. http://dx.doi.org/10.3390/met9040417.

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The selective leaching of zinc from three different basic oxygen steelmaking (BOS) filter cakes by butyric acid was investigated to compare the leaching behaviors of zinc and further to establish the correlation of the zinc leaching performances and the chemical compositions. The effects of acid concentration and the acid to solid (L/S) stoichiometric ratio were studied, with different optimal leaching conditions obtained. BOS-1 showed the lowest leachability with only less than 10% of zinc removed by 0.5 M acid concentration and 90% of the L/S stoichiometric ratio in 10 h. The best zinc selectivity was achieved with BOS-2 at 51.2% of zinc leaching efficiency, with only 0.47% of iron loss under optimal conditions of 1.5 M acid concentration and a 70% stoichiometric ratio. BOS-3 showed the highest leaching of zinc but the optimal conditions depend on the priority consideration. Using 1.0 M acid and 90% stoichiometric ratio for 10 h, the leaching efficiency of zinc was 84.6% with 20% iron loss. The filter cakes and the leaching residues were characterized. The results indicate different zinc and iron leaching behaviors, which were probably related to the storage conditions, zinc containing phases and the leaching parameters.

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Yang, Jin Lin, Hong Mei Zhang, Xiu Juan Su et Shao Jian Ma. « Study on Leaching Zinc Calcine with High Iron ». Advanced Materials Research 826 (novembre 2013) : 118–21. http://dx.doi.org/10.4028/www.scientific.net/amr.826.118.

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In recent years, recovering zinc from zinc calcine with high iron has been a matter of discussion. In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on zinc and iron extraction in zinc calcine with high iron in which the grade of zinc and iron is 53.90% and 19.38%, respectively. Parameters, such as stirring speed, sulfuric acid concentration, liquid to solid ratio and leaching time, were investigated. The results show that leaching time has done nothing to the leaching rate, but has great influence on leaching efficiency. Liquid to solid ratio and sulfuric acid concentration have significant influence on leaching results, and stirring rate has not obvious influence on leaching results. Under the condition of 120g/L sulfuric acid, 6:1 liquid to solid ratio, 55°C leaching temperature and 120min leaching time, the recovery of zinc and iron is 82.24% and 9.64%, respectively. It is obvious that ZnO in zinc calcine is easy to dissolve in acidity solution, which shown in two aspects: high leaching rate and high leaching speed. ZnO can be dissolved entirely in sufficient sulfuric acid in 10min.

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Yang, Jin Lin, Shao Jian Ma, Wei Mo, Jin Peng Feng, Xiu Juan Su et Gui Fang Wang. « Study on Recovering Zinc from Gossan ». Advanced Materials Research 454 (janvier 2012) : 329–32. http://dx.doi.org/10.4028/www.scientific.net/amr.454.329.

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In this paper, the conventional physical separation method such as flotation, gravity separation, magnetic separation, alkaline leaching and sulfuric acid leaching were studied. The effects of grinding fineness, amount of agent, magnetic intensity, roasting temperature, roasting time, the leaching agent and leaching time on the leaching of zinc were investigated, respectively. The results show that the leaching rate of zinc is below 50% in the conventional alkaline leaching, and the leaching rate of zinc is below 85% and the leaching rate of iron is above 35% in sulfuric acid leaching. Compared with XRD pattern of the raw ore, the different diffraction peaks of smithsonite is off in alkaline leaching products. In sulfuric acid leaching, the different diffraction peaks of smithsonite are off in the leaching products when sulfuric acid concentration is less than 60 g/L. After 60 g/L, the different diffraction peaks of smithsonite and siderite are off in the leaching products.

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LI, Yong Jia, et Da Jin Yang. « Study of Leaching Zinc from Difficult Dealt Zinc Oxide Ore with High Silicon in the Alkali ». Advanced Materials Research 1120-1121 (juillet 2015) : 105–9. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.105.

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In this paper, the influencing factors in the process of alkali leaching of refractory zinc oxidize ores were studied. The influence of the particle size, reaction temperature, leaching time, alkali concentration and liquid-solid ratio on the leaching efficiency of zinc were investigated via leaching tests. The results indicate that the particle size has little influence on the leaching efficiency of zinc while the influences of other factors are larger. The optimal leaching condition is: the reaction temperature is 80 °C, the alkali concentration is 4.5 mol/L, and the leaching time is 1.5 h as well as the liquid- solid ratio is 10:1. In such conditions, the leaching efficiency can reach 82.22%.

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Jiang, Tao, Fei-yu Meng, Wei Gao, Yan Zeng, Huan-huan Su, Qian Li, Bin Xu, Yong-bin Yang et Qiang Zhong. « Leaching behavior of zinc from crude zinc oxide dust in ammonia leaching ». Journal of Central South University 28, n^o 9 (septembre 2021) : 2711–23. http://dx.doi.org/10.1007/s11771-021-4803-x.

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Zhang, Qian, Qicheng Feng, Shuming Wen, Chuanfa Cui et Junbo Liu. « A Novel Technology for Separating Copper, Lead and Zinc in Flotation Concentrate by Oxidizing Roasting and Leaching ». Processes 7, n^o 6 (18 juin 2019) : 376. http://dx.doi.org/10.3390/pr7060376.

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In this work, oxidizing roasting was combined with leaching to separate copper, lead, and zinc from a concentrate obtained by bulk flotation of a low-grade ore sourced from the Jiama mining area of Tibet. The flotation concentrate contained 7.79% Cu, 22.00% Pb, 4.81% Zn, 8.24% S, and 12.15% CaO; copper sulfide accounted for 76.97% of the copper, lead sulfide for 25.55% of the lead, and zinc sulfide for 67.66% of the zinc. After oxidizing roasting of the flotation concentrate, the S content in the roasting slag decreased to 0.22%, indicating that most sulfide in the concentrate was transformed to oxide, which was beneficial to leaching. The calcine was subjected to sulfuric acid leaching for separation of copper, lead, and zinc; i.e., copper and zinc were leached, and lead was retained in the residue. The optimum parameters of the leaching process were: a leaching temperature of 55 °C; sulfuric acid added at 828 kg/t calcine; a liquid:solid ratio of 3:1; and a leaching time of 1.5 h. Under these conditions, the extents of leaching of copper and zinc were 87.43% and 64.38%, respectively. Copper and zinc in the leaching solution could be further separated by electrowinning. The effects of leaching parameters on the extents of leaching of copper and zinc were further revealed by X-ray diffraction and scanning electron microscopy analysis.

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Zheng, Xuemei, Shiwei Li, Bingguo Liu, Libo Zhang et Aiyuan Ma. « A Study on the Mechanism and Kinetics of Ultrasound-Enhanced Sulfuric Acid Leaching for Zinc Extraction from Zinc Oxide Dust ». Materials 15, n^o 17 (29 août 2022) : 5969. http://dx.doi.org/10.3390/ma15175969.

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As an important secondary zinc resource, large-scale reserves of zinc oxide dust (ZOD) from a wide range of sources is of high comprehensive recycling value. Therefore, an experimental study on ultrasound-enhanced sulfuric acid leaching for zinc extraction from zinc oxide dust was carried out to investigate the effects of various factors such as ultrasonic power, reaction time, sulfuric acid concentration, and liquid–solid ratio on zinc leaching rate. The results show that the zinc leaching rate under ultrasound reached 91.16% at a temperature of 25 °C, ultrasonic power 500 W, sulfuric acid concentration 140 g/L, liquid–solid ratio 5:1, rotating speed 100 r/min, and leaching time 30 min. Compared with the conventional leaching method (leaching rate: 85.36%), the method under ultrasound increased the zinc leaching rate by 5.8%. In a kinetic analysis of the ultrasound-enhanced sulfuric acid leaching of zinc oxide dust, the initial apparent activation energy of the reaction was 6.90 kJ/mol, indicating that the ultrasound-enhanced leaching process was controlled by the mixed solid product layers. Furthermore, the leached residue was characterized by XRD and SEM-EDS, and the results show that, with ultrasonic waves, the encapsulated mineral particles were dissociated, and the dissolution of ZnO was enhanced. Mostly, the zinc in leached residue existed in the forms of ZnFe2O4, Zn2SiO4, and ZnS.

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Zhang, Jinxia, Jiajing Dong, Fusheng Niu et Chao Yang. « Properties and Kinetics of Selective Zinc Leaching with Choline Chloride and Urea ». Minerals 11, n^o 8 (9 août 2021) : 857. http://dx.doi.org/10.3390/min11080857.

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A choline chloride-urea (ChCl-urea) deep eutectic solvent (DES) was used to experimentally investigate the secondary recovery of zinc from zinc-bearing dust sludge via a leaching process. The effects of varying the liquid–solid ratio, leaching temperature, stirring speed, and leaching time on the zinc leaching efficiency were determined, and the optimum values of these parameters were found to be 15:1, 90 °C, 400 rpm, and 600 min, respectively, at which a leaching efficiency of 86.87% was achieved. XRF and EDS analyses confirmed that the zinc content in the sludge decreased noticeably after leaching, while those of other elements did not, indicating the selective and efficient leaching of zinc. A study of the leaching kinetics showed that the reaction conforms to the nuclear shrinkage model without solid product layer formation, and the calculated apparent activation energy is 22.16 kJ/mol.

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13

Wu, Dan Dan, Shu Ming Wen, Jing Yang, Yi Jie Wang et Chao Lv. « A Study on Leaching of Zinc Oxide Ore in Ammonium Sulfate Solution ». Applied Mechanics and Materials 522-524 (février 2014) : 1463–66. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.1463.

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In this paper, the leaching effect of zinc oxide ore was investigated using ammonium sulfate solution as leaching agent. The effects of temperature, concentration of ammonium sulfate, average particle size and stirring speed on the leaching of zinc oxide ore were studied. The leaching rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Ammonium sulfate solution can therefore be used as an effective leaching agent for zinc extraction from zinc oxide ore.

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Xu, Hong Sheng, Chang Wei, Cun Xiong Li, Yan Song, Zhi Gan Deng et Gang Fan. « Kinetics of Pressure Acid Leaching of Zinc from Zinc Silicate Ore ». Advanced Materials Research 402 (novembre 2011) : 266–71. http://dx.doi.org/10.4028/www.scientific.net/amr.402.266.

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The present work is concerned with the kinetic study of pressure leaching of zinc silicate ore in sulfuric acid solutions. The effects of leaching temperature, particle size, sulfuric acid concentration and agitation speed on the zinc extraction were evaluated. The results obtained show that the zinc extraction increases with increasing sulfuric acid concentration and leaching temperature. The leaching kinetics was analyzed by using a shrinking core model with diffusion control given by: 1-2/3x-(1-x)2/3=Kt, which represented well the experimental data. The apparent activation energy was determined to be 44.56kJ/mol at temperatures ranging between 80 and 140°C.

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Leelarungroj, Kittitat, Suched Likitlersuang, Thanakorn Chompoorat et Dao Janjaroen. « Leaching mechanisms of heavy metals from fly ash stabilised soils ». Waste Management & ; Research : The Journal for a Sustainable Circular Economy 36, n^o 7 (12 juin 2018) : 616–23. http://dx.doi.org/10.1177/0734242x18775494.

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Fly ash is an industrial waste material that is repurposed as a soil stabiliser worldwide. In Thailand, many ground improvement projects utilise mixtures of cement and fly ash to stabilise weak soils. In this study, leaching mechanisms of arsenic, chromium, lead, and zinc from cement and fly ash stabilised soils were investigated in the laboratory. Leaching tests were performed, with different leachants and pH conditions, on cement and fly ash stabilised soils used for soil improvement in road embankment construction projects in Northern Thailand. The results suggested that chemical compounds (CaO and MgO) on fly ash surfaces can control the pH of the fly ash and soil leachant. The dissolution of chromium and zinc was found to be amphoteric and controlled by oxide minerals at a high or low pH. Arsenic leaching was found to be oxyanionic where AsO43- prevented the adsorption of arsenic onto the negatively charged fly ash surface. Different types of leachant also leached out in different amounts of heavy metals.

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Ozberk, E., M. J. collins, M. Makwana, I. M. Masters, R. PülIenberg et W. Bahl. « Zinc pressure leaching at the Ruhr-Zink refinery ». Hydrometallurgy 39, n^o 1-3 (octobre 1995) : 53–61. http://dx.doi.org/10.1016/0304-386x(95)00044-h.

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Niu, Fusheng, Shengtao He, Jinxia Zhang et Chen Wen. « Study on Ultrasonically-Enhanced Deep Eutectic Solvents Leaching of Zinc from Zinc-Containing Metallurgical Dust Sludge ». Metals 12, n^o 11 (30 octobre 2022) : 1856. http://dx.doi.org/10.3390/met12111856.

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In this study, the zinc containing dust and sludge of iron and steel smelting was taken as the research object, and the new ionic liquid of choline-urea was prepared and synthesized as the leaching agent. The conventional and ultrasonic leaching of zinc were compared, and the influence of liquid-solid ratio, temperature, time, ultrasonic power and other conditions on the zinc leaching rate were analyzed. The leaching residue was characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD), and the kinetic equations of ligand leaching based on ultrasonically enhanced metallurgical dust sludge were constructed. The results showed that the choline chloride-urea ionic liquid has a special solubilization ability for ZnO, and the leaching rate of Zn at temperature 60 °C, ultrasonic power 350 W, and leaching time 240 min reached more than 98%. Kinetic fitting of the ChCl-urea leaching process revealed that the ChCl-urea leaching process was in accordance with the nucleation contraction model under both conventional and ultrasonic conditions, and the leaching process was dominated by interfacial mass transfer and solid film layer diffusion control for the reactions, respectively. The activation energies were Ea1 = 44.56 kJ/mol and Ea2 = 23.06kJ/mol

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Skrzekut, Tomasz, Andrzej Piotrowicz, Piotr Noga, Maciej Wędrychowicz et Adam W. Bydałek. « Studies of Selective Recovery of Zinc and Manganese from Alkaline Batteries Scrap by Leaching and Precipitation ». Materials 15, n^o 11 (2 juin 2022) : 3966. http://dx.doi.org/10.3390/ma15113966.

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Recovery of zinc and manganese from scrapped alkaline batteries were carried out in the following way: leaching in H2SO4 and selective precipitation of zinc and manganese by alkalization/neutralization. As a result of non-selective leaching, 95.6–99.7% Zn was leached and 83.7–99.3% Mn was leached. A critical technological parameter is the liquid/solid treatment (l/s) ratio, which should be at least 20 mL∙g−1. Selective leaching, which allows the leaching of zinc only, takes place with a leaching yield of 84.8–98.5% Zn, with minimal manganese co-leaching, 0.7–12.3%. The optimal H2SO4 concentration is 0.25 mol∙L−1. Precipitation of zinc and manganese from the solution after non-selective leaching, with the use of NaOH at pH = 13, and then with H2SO4 to pH = 9, turned out to be ineffective: the manganese concentrate contained 19.9 wt.% Zn and zinc concentrate, and 21.46 wt.% Mn. Better selectivity results were obtained if zinc was precipitated from the solution after selective leaching: at pH = 6.5, 90% of Zn precipitated, and only 2% manganese. Moreover, the obtained concentrate contained over 90% of ZnO. The precipitation of zinc with sodium phosphate and sodium carbonate is non-selective, despite its relatively high efficiency: up to 93.70% of Zn and 4.48–93.18% of Mn and up to 95.22% of Zn and 19.55–99.71% Mn, respectively for Na3PO4 and Na2CO3. Recovered zinc and manganese compounds could have commercial values with suitable refining processes.

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Picazo-Rodríguez, Nallely G., Ma de Jesus Soria-Aguilar, Antonia Martínez-Luévanos, Isaias Almaguer-Guzmán, Josue Chaidez-Félix et Francisco Raul Carrillo-Pedroza. « Direct Acid Leaching of Sphalerite : An Approach Comparative and Kinetics Analysis ». Minerals 10, n^o 4 (17 avril 2020) : 359. http://dx.doi.org/10.3390/min10040359.

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The present work reports the direct leaching of zinc from a sphalerite concentrate in acid media. Lab-scale and pilot-scale experiments were conducted in atmospheric-pressure and low-pressure reactors, respectively. Leaching of zinc and precipitation of iron was achieved in the same stage using different reagents like Fe3+, O2, O3, and Fe2+ (which is continuously oxidized in the leaching solution by H2O2 and O2). The highest percentage of zinc extraction (96%) was obtained in pilot-scale experiments using H2SO4, Fe2+, and O2. Experimental results were compared with those of other researchers to provide a better understanding of the factors influencing the dissolution of zinc. In the first instance, it was determined from analysis of variance that leaching time and the use of an oxidant agent (O2 or O3) were the most influential factors during the direct leaching of zinc from the sphalerite concentrate. Kinetic models were also evaluated to determine the rate-limiting step of the sphalerite leaching; it was concluded that the type of the sulfur layer formed in the residue (porous or non-porous) depends on the type of the oxidant used in the leaching media, which determines the dissolution kinetics of zinc.

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Liu, Chen, Hang Jun He, Duo Qiang Liang, Han Huang, Lu Man Man, Yu Song et Si Qiang Luo. « Influence of the Mechanical Activation on the Reactivity of Germanium-Containing Zinc Neutral Leaching Residue ». Advanced Materials Research 581-582 (octobre 2012) : 868–72. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.868.

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Zinc neutral leaching residue from conventional roast-leach-electrowin often contains a considerable content of germanium. In two-stage leaching process (weak acid leaching and hot acid leaching), dissolution yield of germanium as well as zinc is low due to the compact structure of the residue. In the paper, an attempt of increasing their dissolution yield was made by pretreatment of mechanical activation. The experimental results obtained show that the activated residue has much faster leaching kinetics, and that according to current technical standard operating in Yunnan Chihong Zinc & Germanium Co., Ltd, dissolution of germanium and zinc is increased by 18.12% and 22.93%, respectively. The increase may mainly be due to the structure deformation of the residue by further investigation.

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Prasetyo, Erik, Corby Anderson, Fajar Nurjaman, Muhammad Al Muttaqii, Anton Sapto Handoko, Fathan Bahfie et Fika Rofiek Mufakhir. « Monosodium Glutamate as Selective Lixiviant for Alkaline Leaching of Zinc and Copper from Electric Arc Furnace Dust ». Metals 10, n^o 5 (15 mai 2020) : 644. http://dx.doi.org/10.3390/met10050644.

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The efficacy of monosodium glutamate (MSG) as a lixiviant for the selective and sustainable leaching of zinc and copper from electric arc furnace dust was tested. Batch leaching studies and XRD, XRF and SEM-EDS characterization confirmed the high leaching efficiency of zinc (reaching 99%) and copper (reaching 86%) leaving behind Fe, Al, Ca and Mg in the leaching residue. The separation factor (concentration ratio in pregnant leach solution) between zinc vs. other elements, and copper vs. other elements in the optimum condition could reach 11,700 and 250 times, respectively. The optimum conditions for the leaching scheme were pH 9, MSG concentration 1 M and pulp density 50 g/L. Kinetic studies (leaching time and temperature) revealed that the saturation value of leaching efficiency was attained within 2 h for zinc and 4 h for copper. Modeling of the kinetic experimental data indicated that the role of temperature on the leaching process was minor. The study also demonstrated the possibility of MSG recycling from pregnant leach solutions by precipitation as glutamic acid (>90% recovery).

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Xie, Zeqiang, Tao Jiang, Feng Chen, Yufeng Guo, Shuai Wang et Lingzhi Yang. « Phase Transformation and Zinc Extraction from Zinc Ferrite by Calcium Roasting and Ammonia Leaching Process ». Crystals 12, n^o 5 (29 avril 2022) : 641. http://dx.doi.org/10.3390/cryst12050641.

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Zinc ferrite (ZnFe2O4), one of the major forms of zinc in electric arc furnace dust and zinc leaching residue, is very difficult to chemically dissolve in either acidic or alkaline solutions. It is therefore necessary to study the extraction of zinc from zinc ferrite to achieve the full recovery of the zinc resources. In this paper, CaO was used to degrade the structure of zinc ferrite and then the ammonia leaching method was applied to recover zinc. The thermodynamic analysis indicated that the zinc ferrite could react with CaO to form zinc oxide and dicalcium ferrite. The CaO–Fe2O3–ZnO phase diagram shows that Ca2Fe2O5 can be in equilibrium with ZnO rather than ZnFe2O4 at a higher CaO area. The experimental results indicated that the phase transformation of zinc ferrite, reacted with CaO, to zinc oxide and dicalcium ferrite could be completely achieved with a CaO addition of 2.4:1 (mole ratio). The peaks of zinc ferrite in the X-ray diffraction (XRD) patterns cannot be clearly observed after calcium roasting at 1220 °C for 2 h. The ammonia leaching tests showed that the zinc leaching rate was about 90% under optimal roasting conditions.

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Ferella, Francesco, Ida De Michelis, Francesca Beolchini, Valentina Innocenzi et Francesco Vegliò. « Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution ». International Journal of Chemical Engineering 2010 (2010) : 1–13. http://dx.doi.org/10.1155/2010/659434.

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The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a24full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 gL-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.

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Ma, Aiyuan, Xuemei Zheng, Lei Gao, Kangqiang Li, Mamdouh Omran et Guo Chen. « Enhanced Leaching of Zinc from Zinc-Containing Metallurgical Residues via Microwave Calcium Activation Pretreatment ». Metals 11, n^o 12 (28 novembre 2021) : 1922. http://dx.doi.org/10.3390/met11121922.

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Given the shortage of zinc resource, the low utilisation efficiency of secondary zinc resource, and the crucial problem that the synchronous dissolution of zinc from different mineral phases, an activation pretreatment method merged with calcium activation and microwave heating approach was proposed to enhance the zinc leaching from complex encapsulated zinc-containing metallurgical residues (ZMR). Results indicated that under the optimal pretreatment conditions, including microwave activation temperature of 400 °C, CaO addition of 25% and activation time of 20 min, the zinc leaching rate reached 91.67%, which was 3.9% higher than that by conventional roasting pretreatment. Meanwhile, microwave heating presents excellent treatment effects, manifested by the zinc leaching rates, all exceeding that of conventional roasting under the same conditions, while the process temperature is decreased by 200 °C. In addition, XRD and SEM-EDS analysis denoted that microwave calcification pretreatment can effectively promote the transformation of the refractory zinc minerals like Zn2SiO4 and ZnFe2O4 into the easily leachable zinc oxides. The distinctive selective heating characteristics of microwave heating strengthened the dissociation of mineral inclusion, and the generated cracks increased the interfacial reaction area and further enhancing the leaching reaction of zinc from ZMR.

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Jankola, W. A. « Zinc pressure leaching at Cominco ». Hydrometallurgy 39, n^o 1-3 (octobre 1995) : 63–70. http://dx.doi.org/10.1016/0304-386x(95)00045-i.

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Krysa, B. D. « Zinc pressure leaching at HBMS ». Hydrometallurgy 39, n^o 1-3 (octobre 1995) : 71–77. http://dx.doi.org/10.1016/0304-386x(95)00046-j.

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Bulaev, Aleksandr, Vitaliy Melamud et Anna Boduen. « Two-Stage Agitation Leaching of Old Flotation Tailings ». Solid State Phenomena 298 (octobre 2019) : 116–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.298.116.

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The goal of the present work was to develop hydrometallurgical approaches based on acid leaching for selective extraction of base metals from the sample of old flotation tailings as well as obtaining solution, which can be used for leaching of substandard copper-zinc concentrate. Old flotation tailings contained 23.2% of iron, 0.36% of copper, and 0.23% of zinc. Copper-zinc concentrate contained 23.8% of iron, 16% of copper, and 5.3% of zinc. Agitation leaching of old flotation tailings with distilled water and sulfuric acid solutions (of 0.5 to 10% H2SO4) for 3 h at pulp density of 20% made it possible to extract of 26 to 34% and of 58 to 70% of copper and zinc, respectively. Concentrations of copper and zinc in the pregnant solutions were of 0.19 to 0.25 g/L and of 0.27 to 0.32 g/L, respectively. The increase in H2SO4 concentration up to 10% did not lead to significant increase in base metals extraction but led to significant increase in iron ions concentration in the pregnant solutions. Pregnant solution obtained during the leaching with water contained less than 1 g/L of iron ions, while that obtained during the leaching with 10% sulfuric acid contained about 9 g/L of iron ions. Therefore, two-stage acid leaching with water and 10% sulfuric acid was proposed for selective extraction of non-ferrous metals in the first stage and obtaining of ferric iron solution in the second stage. Two-stage leaching at pulp density of 40% with water made it possible to extract 31 and 64% of copper and zinc, respectively. It was shown, that second stage did not allow to increase non-ferrous metals extraction but made it possible to obtain solution containing 11g/L of ferric iron. This pregnant solution was used for oxidative leaching of copper-zinc concentrate. Leaching at 80°C made it possible to extract 13 and 48% of copper and zinc, respectively.

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Fomchenko, N. V., et M. I. Muravyov. « Selective leaching of zinc from copper-zinc concentrate ». Applied Biochemistry and Microbiology 53, n^o 1 (janvier 2017) : 73–77. http://dx.doi.org/10.1134/s0003683817010197.

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Prica, Miljana, Milena Dalmacija, Bozo Dalmacija, Jelena Trickovic et Snezana Maletic. « The use of cardboard factory sludge in the remediation of zinc contaminated sediment ». Journal of the Serbian Chemical Society 77, n^o 8 (2012) : 1097–107. http://dx.doi.org/10.2298/jsc111111022p.

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Paper and cardboard factory sludges are generated by various processes during pulp, cardboard and paper production, and the increasing quantities produced make the disposal of this sludge a problem. This study investigates the use of cardboard factory sludge as a stabilizing agent in the solidification/stabilization (S/S) treatment of zinc polluted sediment. Semidynamic and toxicity leaching tests were conducted to assess the effectiveness of the solidification/stabilization treatment and long-term zinc leaching behaviour. A diffusion-based model was used to elucidate the controlling leaching mechanisms. The applied S/S treatment was effective in immobilizing zinc, and the controlling leaching mechanism appeared to be diffusion, which indicates that a slow leaching of zinc could be expected when cardboard mill sludge is applied as a S/S agent.

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Yang, Jin Lin, Hong Mei Zhang, Gui Fang Wang, Shao Jian Ma et Min Zhang. « Sulfuric Acid Leaching on Low Grade Oxide Ore ». Advanced Materials Research 826 (novembre 2013) : 122–25. http://dx.doi.org/10.4028/www.scientific.net/amr.826.122.

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In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on metal extraction in a low grade complex gossan ore in which the grade of zinc and iron is 13% and 40.2%, respectively. Parameters, such as sulfuric acid concentration, liquid to solid ratio and leaching temperature, were studied. The results show that the zinc leaching rate is almost 80%, while the iron leaching rate is about 45% used strong acid with 200g/L. It can be seen from the results that sulfuric acid leaching could not effectively recover zinc from gossan ores studied in this paper because of iron dissolving greatly.

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Li, Jia Feng, Lin Lin Tong, Qiao Chen, Zhe Nan Jin et Hong Ying Yang. « Bioleaching Experiments on a Low-Grade Complex Zinc Ore from Inner Mongolia ». Solid State Phenomena 262 (août 2017) : 155–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.155.

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When dealing with a low-grade complex Zinc ore from Inner Mongolia, problems of low leaching rate, high energy consumption, low economic benefits and pollution were encountered. To treat this low-grade zinc ore economically and effectively, bioleaching was used. This approach produces reliable data for an environmentally friendly and efficient processing of the zinc ore. The results indicate that Zinc occurs in the ore mainly as sphalerite, the latter also containing Indium. The experimental results demonstrated an excellent leaching performance: A leaching rate of nearly 100% is achieved at a temperature of 45°C, a pulp concentration of 10%, an initial pH of 1.8, and an aeration rate of 0.8m3/h. In the initial stage the leaching rate is higher than at the end. It starts with 85% of zinc leaching rate in three days. The Indium in the sphalerite is leached almost completely. This makes a further comprehensive use of such resources possible.

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Du, Yunpeng, Xiong Tong, Xian Xie, Wenjie Zhang, Hanxu Yang et Qiang Song. « Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process ». Minerals 11, n^o 6 (31 mai 2021) : 586. http://dx.doi.org/10.3390/min11060586.

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Zinc-leaching residue (ZLR) is a strongly acidic hazardous waste; it has poor stability, high heavy metal levels, and releases toxic elements into the environment. ZLR has potential as a valuable resource, because it contains elevated levels of zinc and silver. In this paper, the recovery of zinc (Zn) and silver (Ag) from ZLR wastes from zinc hydrometallurgy workshops using water leaching followed by flotation was studied. During water leaching experiments, the zinc and copper recovery rates were 38% and 61%, respectively. Thereafter, various flotation testing parameters were optimized and included grinding time, reagent dosages, pulp density, flotation time, and type of adjuster. Experimental results demonstrated this flotation method successfully recycled Ag and Zn. A froth product containing more than 9256.41 g/t Ag and 12.26% Zn was produced from the ZLR with approximately 80.32% Ag and 42.88% Zn recoveries. The toxicity characteristic leaching procedure (TCLP) results indicated the water-leaching flotation process not only recycled valuable metals such as zinc and silver in zinc-containing hazardous wastes but lowered the hazardous waste levels to those of general wastes and recycled wastes in an efficient, economical, and environmentally friendly way.

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Wang, Jie, Wei Xiong et Bao Ping Zhang. « Experimental Study on Zinc Leaching of Blast Furnace Gas Ash by Ammonia Leaching ». Advanced Materials Research 962-965 (juin 2014) : 780–83. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.780.

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Blast furnace gas ash is one of the main solid wastes in iron and steel enterprise. The recovery of zinc from gas ash can result in considerable economic and environmental benefits. The effect of NH3/NH4+, L/S, [NH3]T and leaching time on the zinc leaching rate of blast furnace gas ash by using ammonia leaching process had been investigated in this paper. The results show that L/S and NH3/NH4+ are the main influence factors under the experimental condition. The optimal conditions for leaching process are: NH3/NH4+=2:1, L/S=4:1, [NH3]T =5mol/L, and the leaching time is 3 hours. The zinc leaching rate is 82.84% under the optimized conditions. The lead content in leaching solution is high, so the main task is to improve the removal rate of lead in the purification process.

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Deng, F. L., G. X. Xu, W. W. Fan, S. Li et R. X. Ma. « Atmospheric curing of zinc sulfide concentrate by sulfuric acid below 300°C ». Journal of Mining and Metallurgy, Section B : Metallurgy, n^o 00 (2022) : 16. http://dx.doi.org/10.2298/jmmb220302016d.

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Because the traditional roasting-leaching-electrowinning zinc hydrometallurgy process has a small sulfuric acid sales radius and a high inventory pressure, the process of direct leaching zinc concentrate is gaining popularity. but the pressurized leaching process is a high-pressure condition, which requires strict equipment material and high safety requirements. Furthermore, the atmospheric leaching efficiency is low and generally introduces impurities and chloride ions, which increase the cost of subsequent decontamination. Therefore, a new environmentally friendly hydrometallurgy extraction method of zinc was proposed: an atmospheric pressure medium temperature sulfuric acid curing-leaching process. In an open-air condition, zinc sulfide concentrate was cured with sulfuric acid at different acid-to-ore ratios and heated to 220?C~260?C for a different time, then leaching the cured product. The effects of temperature, curing time, acid-to-ore ratio and sulfuric acid concentration on the leaching ratio of zinc (hZn) were studied. The results demonstrated that hZncould reach as high as 98.23% under the optimized conditions of temperature 240?C, curing time 2.5 hours, acid-to-ore ratio 1.4:1 and sulfuric acid concentration 60 wt.%. The leaching residue ratio is 6%, with silicate accounting for the majority of it. The kinetic results support the shrinking core model, which is controlled by an interface chemical reaction with an apparent activation energy of 43.158 kJ/mol.

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Panayotova, Marinela, et Vladko Panayotov. « Studies on zinc recovery from technogenic waste ». E3S Web of Conferences 295 (2021) : 03008. http://dx.doi.org/10.1051/e3sconf/202129503008.

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Results from laboratory experiments are presented on extraction of zinc available in waste from lead-zinc metallurgy, mixed with lead-zinc flotation tailings and some waste rock, by leaching it under atmospheric conditions with sulfuric acid (H2SO4) solutions (5 and 10 wt. %) and 30 % hydrogen peroxide in the temperature range of 25 - 80 °C, at leaching time 30 - 120 min. Material leaching with 10 % H2SO4 solution at 70 °C for one hour brings into pregnant leach solution (PLS) around 80 % of zinc available. Imposing an electrochemical impact during the leaching process increases the quantity of leached zinc by around 5 %. Direct electrowinning from the PLS obtains zinc metal of grade 75-76 %. The suggested treatment removes metals-pollutants from accumulated mixed technogenic waste therefore rendering it more environmentally friendly. Experiments showed that old mixed waste from mining, mineral processing and metallurgy activities merits further studies as secondary source of metals.

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Wang, Zhongxue, Yun He, Weian Wang, Yongkun Yang, Guoxing Qiu et Xiaoming Li. « Study on Preparation of Nano-ZnO by Zinc Hypoxide in Rotary Hearth Furnace ». Metals 12, n^o 8 (17 août 2022) : 1364. http://dx.doi.org/10.3390/met12081364.

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To realize the high value-added utilization of zinc hypoxide in a rotary hearth furnace, nano-ZnO was prepared by H2SO4 wet leaching combined with the Na2CO3 precipitation process. The effects of different process conditions on the leaching rate of Zn were analyzed, and the feasibility of preparing nano-ZnO from zinc hypoxide was discussed. The results showed that the optimal process conditions for H2SO4 leaching of zinc hypoxide in a rotary hearth furnace were as follows: H2SO4 concentration 2.0 mol·L−1, leaching temperature 60 °C, leaching time 90 min, and liquid-solid ratio 8:1. Under these conditions, the leaching rate of Zn reached 95%. The calculation results of leaching kinetics showed that the restrictive link of the H2SO4 leaching process was a chemical reaction process; the apparent activation energy was 14.45 kJ·mol−1; and the reaction order was 0.6. The precursor obtained by Na2CO3 precipitation treatment was Zn5(OH)6(CO3)2. After calcination at 400 °C, the nano-ZnO with a diameter of less than 100 nm and length greater than 1 μm was obtained. H2SO4 leaching combined with the Na2CO3 precipitation process provided a new approach for high value-added utilization of zinc hypoxide in a rotary hearth furnace.

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Guo, Jihao, Hongao Xu, Bo Li, Yonggang Wei et Hua Wang. « Leaching kinetics of copper and valuable metal extraction from copper-cadmium residues of zinc hydrometallurgy by oxidation acid leaching ». International Journal of Chemical Reactor Engineering 20, n^o 3 (5 novembre 2021) : 295–303. http://dx.doi.org/10.1515/ijcre-2021-0077.

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Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

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Yang, Li Jiao, Nan Chun Chen, Xia Ping Zhong, Jun Gao, Yao Xiu Lang, Zhen Feng Wang, Chang Miao Liu et Zhao Yang Wu. « Factors on Leaching Zinc and Copper from Zinc Leach Residue ». Key Engineering Materials 633 (novembre 2014) : 169–72. http://dx.doi.org/10.4028/www.scientific.net/kem.633.169.

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It is found that cuprous sulfite, zinc sulfate and zinc sulfide were the main phases of copper and zinc in zinc leach residue, through analyzing its composition and phase characteristics by XRF and XRD. The method that cooperate sulfuric acid leaching with oxidant was chosen. 60 g/L H2SO4 at 60 °C for 2 h with 4% KMnO4 and liquid/solid ratio of 5..1, 84.29 % of Cu and 92.02 % of Zn are extracted. The ion concentration of copper and zinc are tested by UV-VIS spectrophotometer and EDTA titration respectively. The results show that the amount of acid is sufficient for leaching at the condition of 60 g/L H2SO4 and liquid/solid ratio of 5..1. At the same time, copper change from low valence into high valence after adding KMnO4 which strengthen the leaching, and the chemical reaction can reach balance at 60 °C for 2 h. This method has good extraction effect on copper and zinc.

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Guerra, R. N. G., Carlos A. Nogueira et Fernanda Margarido. « Leaching Studies of Spent Zinc-Manganese Alkaline Batteries with Sulphuric Acid ». Materials Science Forum 587-588 (juin 2008) : 763–67. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.763.

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The hydrometallurgical processing of metal bearing residues is one of the established routes envisaging metals recovery. In these processes, the leaching operation plays a central role as allows the solubilization of metals for further separation and recovery as pure products. This route can be applied to spent domestic batteries recycling, which studies on sulphuric acid leaching of spent alkaline batteries are reported in this paper. Material samples used in the trials were prepared concerning the real proportion of the most common sizes and shapes of batteries found in the usual stream of this type of wastes. The research involved the evaluation of some factors which affect leaching yields namely temperature, reaction time and stirring speed, through a two-level factorial design methodology and analysis of variance. In this study, other factors related with leachant concentration and stoichiometry were maintained constant. Zinc leaching yields were generally high and even near 100% when the high levels of the variables were used, meaning that zinc oxides present in the electrodes are very reactive to acid leachant. The variables had all positive effects being temperature the most significant factor (confidence level 99%) while the other factors were less significant (98.8% for time and 95% for stirring speed). Concerning manganese, leaching yields obtained were more dependent from the factors, being also positive and varying from 11% (for low levels of factors combination) to 89% (for high levels of factors combination). Temperature and time were highly significant (confidence levels above 99.9%) while stirring speed was less significant (97%). Contamination of leach liquors with iron was also evaluated since it is an impurity which requires special attention during the process development. For the higher levels of the factors (t = 1 h, T=80°C and ω=400 rpm) the final solution contained 10 g/L Zn, 15 g/L Mn and 3.2 g/L Fe. The removal of the iron from the solution is a necessary step prior to the separation and recovery of zinc and manganese.

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Pedrosa, Fátima, Marta Cabral, Fernanda Margarido et Carlos A. Nogueira. « Recycling of Exhausted Batteries and EAF Dusts by Leaching with Several Aqueous Media ». Materials Science Forum 730-732 (novembre 2012) : 636–41. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.636.

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Zinc is a base metal present in several products of general use, and therefore found in numerous residues and end-of-life products. The two main sources of zinc containing wastes are spent Zn-MnO2 portable batteries and electric arc furnace (EAF) dusts from steelmaking plants. The recovery of metals from these residues by appropriate recycling processes is mandatory due to environmental, economic and resource conservation issues. Concerning the similar composition of both residues, their simultaneous processing can be envisaged. The research herein described consists on the hydrometallurgical treatment of zinc bearing waste, where several leaching routes for solubilising metals, mainly zinc, are studied. The leaching of shredded batteries and EAF dusts was carried out using three different leaching solutions containing sulfuric acid, hydrochloric acid or ammonium chloride. The acid leaching of zinc in the oxide form (zincite) using both acids, was very efficient and quick, allowing the recovery of practically all Zn contained in batteries and about of 80% of Zn in dusts. Regarding to the leaching media the behaviour of lead oxides present in dusts was different, being insoluble with H2SO4 and partially soluble with HCl (40-90% yield, depending on conditions). For battery waste stream, manganese is also other important metal, which oxides were only partially soluble in acid media, attaining a maximum leaching yield of 90% Mn. Iron, considered a contaminant in both residues, was partially leached and required further purification steps. The use of an ammoniacal medium (NH4Cl) was very selective for zinc, being iron practically insoluble. However, the maximum zinc leaching yield attained for both residues was only near 60%. Under these conditions, manganese contained in batteries was very insoluble while lead from dusts was leached up to 70% due to the relative solubility of lead chloride. This research showed that hydrometallurgical treatment can provide versatile solutions for recycling metals from Zn waste. Ammoniacal leaching allows high selectivity for zinc but less recovery efficiency is attained, while acid leaching allows higher metal recovery yields but unwanted elements like iron are co-dissolved.

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Mao, Ying Bo, Zhi Cong Wei, Jian Jun Fang, Shan Wang et Tie Min Zhang. « Studying on Leaching Zinc Oxide Ore in the System of H₂SO₄ ». Advanced Materials Research 785-786 (septembre 2013) : 1087–90. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.1087.

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Leaching test on the Oxidized Zinc Ore coming from Yunnan Province is studied in the H2SO4 system;Systematic studies are made to show the effects of various factors on the leaching rate of zinc. The optimum conditions for leaching is finally confirmed, namely the grinding size is 75% of-0.074mm, concentration of sulfuric acid 15%, temperature 60°C, solid to liquid ratio 3:1, and leaching time 2.5h. Ultimately, the leaching rate of Zn could reach more than 59%.

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Turan, Mehmet Deniz, Galymzhan Karamyrzayev et Rashid Nadirov. « Recovery of zinc from copper smelter slag by sulfuric acid leaching in an aqueous and alcoholic environment ». Chemical Bulletin of Kazakh National University, n^o 4 (22 octobre 2021) : 4–11. http://dx.doi.org/10.15328/cb1244.

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The content of zinc in copper smelter slags obtained from pyrometallurgical copper production is comparable to the content of this metal in zinc ores. Therefore, these slags are considered a valuable secondary resource for zinc recovery. At the same time, the features of the mineralogical composition of the slag make the extraction of zinc from it very problematic. Most of the zinc is concentrated in the refractory zinc ferrite (ZnFe2O4). To avoid the formation of a viscous pulp when leaching copper smelter slag with an aqueous solution of sulfuric acid, in this work, the slag was leached with sulfuric acid also in isopropanol and n-pentanol, under the following conditions: 0.5 M H2SO4, pulp density 50 g/L, magnetic stirrer rotation speed 600 rpm. The influence of the duration and temperature of leaching milled (≤100 μm) copper smelter slag of the Balkhash copper smelter on the extraction of zinc into solution was investigated. It was found that the maximum zinc recovery into an aqueous solution was 75 ± 2% at 363 K and 210 min. Replacing water with isopropanol or n-pentanol led to an increase in zinc recovery to 82 ± 2% at 210 min and a lower temperature (353 K) than in an aqueous environment. An increase in temperature to 383 K during leaching in n-pentanol made it possible to extract 92 ± 2% of zinc. A shrinking core model was used to describe the kinetics of the zinc leaching process. It was found that the limiting stage of the process under all investigated conditions is the chemical leaching reaction. Some kinetic characteristics of the leaching process were calculated, in particular, the apparent reaction rate constants, as well as the activation energy.

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Ma, Shao Jian, Jin Lin Yang, Gui Fang Wang, Wei Mo et Xiu Juan Su. « Alkaline Leaching of Low Grade Complex Zinc Oxide Ore ». Advanced Materials Research 158 (novembre 2010) : 12–17. http://dx.doi.org/10.4028/www.scientific.net/amr.158.12.

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Alkaline leaching is an important way for treating low grade metal oxide ore, which has some advantages such as low corrosion and low pollution compared to acidic leaching. In order to recover the zinc from a low grade complex zinc oxide ore in which the grade of Zn and Fe are 13 wt.% and 40.2 wt.%, respectively, and 52.8% of Zn is contained in siderite, 34.63% in limonite and 11.55% in smithsonite, this paper presents a preliminary investigation of this type of ore by alkaline leaching method. In this study, ammonia-ammonium chloride and ammonia-ammonium carbonate were used as the leaching reagents. The effects of alkaline concentration, leaching time, leaching temperature and liquid to solid ratio (L/S) were studied, respectively. The results show that 43.15% of initial Zn content was extracted adopting ammonia-ammonium chloride as the leaching reagent in 4.5M at 30°C for 3h with a liquid to solid ratio of 4:1, while 43.07% of Zn recovery was achieved employing ammonia-ammonium carbonate as the leaching reagent at 5M, 30°C and 4:1(L/S). The low leaching rate of Zn is probably attributed to that the zinc contained in siderite was not extracted completely because Zn and Fe exist as isomorphism in siderite.

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Xiao, Junhui, Kai Zou, Wei Ding, Yang Peng et Tao Chen. « Extraction of Lead and Zinc from a Rotary Kiln Oxidizing Roasting Cinder ». Metals 10, n^o 4 (2 avril 2020) : 465. http://dx.doi.org/10.3390/met10040465.

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In this study, sulfuric acid leaching and gravity shaking-table separation by shaking a table are used to extract lead and zinc from a Pb-Zn oxidizing roasting cinder. The oxidizing roasting cinder—containing 16.9% Pb, 30.5% Zn, 10.3% Fe and 25.1% S—was obtained from a Pb-Zn sulfide ore in the Hanyuan area of China by a flotation-rotary kiln oxidizing roasting process. Anglesite and lead oxide were the main Pb-bearing minerals, while zinc sulfate, zinc oxide and zinc ferrite were the main Zn-bearing minerals. The results show that a part of lead contained in lead oxide is transformed to anglesite, and a 3PbO·PbSO4·H2O-dominated new lead mineral phase after acid leaching. A zinc leaching efficiency of 96.7% was obtained under the leaching conditions used: a leaching temperature of 55 °C; a leaching time of 90 min; a sulfuric acid dosage of 20%; a sulfurous acid dosage of 4%; a cinder particle size of <0.3 mm; and a solid-liquid ratio of R = 1:4. After the gravity shaking-table separation, a lead concentrate with 50.2% Pb, 2.33% Zn and lead recovery of 86.0% was produced. The main chemical compounds in leaching residue are anglesite, 3PbO·PbSO4·H2O, SiO2 and ZnFe2O4, while the main chemical compounds in lead concentrate are anglesite, 3PbO·PbSO4·H2O and SiO2.

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Jiang, Jia Chao, Xiao Yu Yang et You Cai Zhao. « Recovery of Zinc from EAF Dust by Alkaline Extraction ». Advanced Materials Research 113-116 (juin 2010) : 2299–304. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.2299.

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In this paper, a series of lab-scale experiments have been focused on the zinc recovery from electric arc furnace (EAF) dust by alkaline extraction, combining with the novel alkaline zinc electrowinning technology. Effects of several leaching variables, i.e. leaching time (1-3 h), NaOH concentration (150-400 g/L), solid/liquid ratio (S/L, 1/5-1/12), temperature (30-90 °C) and stirring speed (300-500 rpm) on zinc recovery (%) were investigated. Around 84 %Zn and 92 % Pb were respectively recovered when the leaching process was operated with 250 g/L NaOH and S/L 1/10 at 90 °C for 2 h. After Pb was selectively removed by sodium sulfide precipitation, the alkaline zinc solution was subjected to electrolysis and zinc powder with a purity of 98.5 % was then obtained. The leaching residue is suitable for safe disposal, while the purifying residue can be marketed for lead recovering.

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ANGELOV, Todor. « Industrial Scale Testing and Evaluation of Silver Recovery Process ». Eurasia Proceedings of Science Technology Engineering and Mathematics 19 (14 décembre 2022) : 68–77. http://dx.doi.org/10.55549/epstem.1219169.

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In this paper an industrial scale testing and evaluation of a silver recovery process for treating silver-containing materials is presented. The process that is based on the thiourea leaching, followed by silver cementation allows for recovery of the majority of silver as a metallic product. The thiourea leaching was developed specifically for the zinc cake residue, produced from the conventional zinc roast-leaching process at the KCM 2000 AD (Bulgaria), which contains up to 200 g/t silver. The material has a complex zinc ferrite dominated mineralogy with minor zinc hydrosulfate, gypsum, anglesite and plumbojarosite. The feed zinc cake residue is washed with water to remove water soluble zinc by pulping it into 25-30% solids slurry. The washing is carried out in 60 minutes and the resulted slurry is sent to the solid/liquid separation section for filtration. The resulted solids are sent to thiourea leaching and the zinc-containing solution is sent for further zinc recovery. The washed (water-soluble zinc free) solids is pulped into 20% solids slurry. Using thiourea as lixiviant, ferric iron as oxidant, sodium metabisulfite as a reductant and sulfuric acid for pH control, the leaching is performed for 35 minutes at 35oC. Within the leaching process the operating conditions are controlled to allow high silver extraction, while reducing the detrimental effects of thiourea degradation. Silver is recovered from the pregnant leach solution by cementation that results in the formation of a high-grade silver cement product. Iron powder is used as a cementation agent to recover over 94% silver at ambient temperature for 90 minutes. Details of the development work and key process steps are described. The operational data and outcomes of the industrial scale testing are presented along with process performance evaluation.

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Rudnik, Ewa, Grzegorz Włoch et Leszek Szatan. « Comparative studies on acid leaching of zinc waste materials ». Metallurgical Research & ; Technology 115, n^o 1 (22 novembre 2017) : 110. http://dx.doi.org/10.1051/metal/2017076.

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Three industrial waste materials were characterized in terms of their elemental and phase compositions, leaching behaviour in 10% sulfuric acid solution as well as leaching thermal effects. Slag from melting of mixed metallic scrap contained about 50% Zn and 10% Pb. It consisted mainly of various oxides and oxy-chlorides of metals. Zinc spray metallizing dust contained about 77% Zn in form of zinc and/or zinc-iron oxides, zinc metal and Zn-Fe intermetallic. Zinc ash from hot dip galvanizing was a mixture of zinc oxide, metallic zinc and zinc hydroxide chloride and contained about 80% Zn. Dissolution efficiency of zinc from the first material was 80% (independently on the solid to liquid ratio, 50–150 kg/m3), while decrease of the efficacy from 80% to 60% with increased solid to liquid ratio for the two remaining materials was observed. Both increase in the temperature (20 °C to 35 °C) and agitation rate (300 rpm to 900 rpm) did not improve seriously the leaching results. In all cases, transfer of zinc ions to the leachate was accompanied by different levels of solution contamination, depending on the type of the waste. Leaching of the materials was exothermic with the similar reaction heats for two high oxide-type products (slag, zinc ash) and higher values for the spray metallizing dust.

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Yang, Kun, Shi-wei Li, Li-bo Zhang, Jin-hui Peng, Ai-yuan Ma et Bao-bao Wang. « Effects of Sodium Citrate on the Ammonium Sulfate Recycled Leaching of Low-Grade Zinc Oxide Ores ». High Temperature Materials and Processes 35, n^o 3 (1 mars 2016) : 275–81. http://dx.doi.org/10.1515/htmp-2014-0215.

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AbstractThe effects of sodium citrate on ammonium sulfate recycled leaching of low-grade zinc oxide ores were studied. By applying various kinds of detection and analysis techniques such as chemical composition analysis, chemical phase method, scanning electron microscopy and energy dispersive spectrum (SEM/EDS), X-ray diffraction (XRD) and Fourier-transforming infrared spectrum (FT-IR), zinc raw ore, its leaching slag and the functional mechanism of sodium citrate were investigated. Based on a comprehensive analysis, it can be concluded that in contrast to hemimorphite (Zn4Si2O7(OH)2 · H2O), amorphous smithsonite (ZnCO3) and zinc silicate (Zn2SiO4) prove to be refractory phases under ammonium sulfate leaching, while sodium citrate has a better chelating action with the refractory phases, resulting in a higher zinc leaching rate. Under conditions of [NH3]/[NH3]T molar ratio being 0.5, [NH3]T being 7.5 mol/L, [Na3C6H5O7] being 0.2 mol/L, S/L ratio being 1:5, temperature being 303 K, holding time being 1 h in each of the two stages, and stirring rate being 300 rpm, the leaching rate of zinc reached 93.4%. In this article, sulfate ammonium recycled technology also reveals its unique advantage in processing low-grade zinc oxide ores accompanied by high silicon and high alkaline gangue.

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Ma, Aiyuan, Xuemei Zheng, Song Li, Yihong Wang et Shan Zhu. « Zinc recovery from metallurgical slag and dust by coordination leaching in NH 3 –CH 3 COONH 4 –H 2 O system ». Royal Society Open Science 5, n^o 7 (juillet 2018) : 180660. http://dx.doi.org/10.1098/rsos.180660.

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Metallurgical slag and dust (MSD) from lead and zinc smelting, steel dust and galvanized steel scrap are important secondary sources of zinc and other valuable metals. This paper describes the production feasibility and rationality of a cleaner zinc recovery process using MSD and a hydrometallurgical method. It was found that the addition of CH 3 COONH 4 to a NH 3 –H 2 O system promotes zinc extraction, and 83.76% of zinc could be dissolved and recovered from the MSD under the following conditions: total ammonia concentration of 5 mol l −1 , stirring speed of 300 r.p.m., ammonia/ammonium ratio of 1 : 1, solid/liquid ratio of 1 : 5, leaching temperature of 25°C and a leaching time of 60 min. A leaching kinetic study indicates that the leaching process is controlled by the diffusion and interface transfer and that the reaction apparent activation energy is 22.66 kJ mol −1 . Fourier transform infrared spectroscopy and electrospray ionization mass spectrometry analysis showed that zinc can combine with the carboxylate anion to form Zn complexes such as [Zn 2 (Ac) 3 (NH 3 ) 2 ] + . Zn 2 SiO 4 , ZnS and ZnFe 2 O 4 in NH 3 –CH 3 COONH 4 –H 2 O system did not disappear according to X-ray diffraction analysis for leaching residue.

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Li, Cun Xiong, Chang Wei, Hong Sheng Xu, Ji Qiang Liao, Zhi Gan Deng et Gang Fan. « Leaching Behaviour of Metals from a Sphalerite Concentrate in Sulfuric Acid-Oxygen System ». Advanced Materials Research 201-203 (février 2011) : 1725–31. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.1725.

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Leaching behaviors of zinc, copper, indium and iron from a sphalerite concentrate in sulfuric acid-oxygen system has been investigated in the present paper. Various parameters were studied including particle size, concentration of sulfuric acid, partial pressure of oxygen, leaching temperature, and leaching time. The experimental data indicated that under the typical plant conditions employed up to 99% zinc , 85% copper and 90% indium extraction were achieved. The mineralogical analysis of the residue showed that the main minerals are elemental sulphur, unreacted pyrite and quartz, the amount of sulphide sulphur oxidized to sulfur during leaching is 81%. This process provides an effective way for the extraction of zinc, copper and indium from sphalerite concentrate.

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