zinc hydrometallurgy
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Author(s):  
Jihao Guo ◽  
Hongao Xu ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang

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.


2021 ◽  
Vol 170 ◽  
pp. 107030
Author(s):  
Abd. Maihatchi Ahamed ◽  
M.N. Pons ◽  
Q. Ricoux ◽  
S. Issa ◽  
F. Goettmann ◽  
...  

Author(s):  
Fuxian Yang ◽  
Yubo Xing ◽  
Zhigan Deng ◽  
Chang Wei ◽  
Xingbin Li ◽  
...  

Abstract Iron removal is an important step in zinc hydrometallurgy, and hematite process not only can effectively remove iron, but also is environmentally friendly and has certain economic benefits, so it has great application potential in zinc hydrometallurgy. The oxidative hydrolysis of Fe(Ⅱ) was studied by the change of ions in solution with different initial ferrous ion concentration. Meanwhile, the oxidation rates of Fe(Ⅱ) at different initial Zn(Ⅱ) concentrations were also studied. The results show that temperature has an important influence on the oxidative hydrolysis of Fe(Ⅱ). Increasing the temperature can inhibit the formation of complex and make more Fe(Ⅱ) precipitate directly in the form of hematite, which is not limited by the hydrolysis rate of Fe(Ⅲ). The oxidation reaction of Fe(Ⅱ) approximately conforms to the second order reaction rate. Zinc sulfate can promote the oxidation of Fe(Ⅱ). When the initial Zn(Ⅱ) concentration was 20, 40, 60 and 80 g/L, the oxidation kinetic constants of Fe(Ⅱ) were 2.433, 4.492, 10.106 and 14.857 L·mol−1·min−1, respectively.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 586
Author(s):  
Yunpeng Du ◽  
Xiong Tong ◽  
Xian Xie ◽  
Wenjie Zhang ◽  
Hanxu Yang ◽  
...  

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.


JOM ◽  
2021 ◽  
Author(s):  
Julien Comel ◽  
Eric Meux ◽  
Nathalie Leclerc ◽  
Sebastien Diliberto ◽  
Philippe Pierrat ◽  
...  

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 387
Author(s):  
Yiting Liang ◽  
Yuanhua Zhang ◽  
Yonggang Li

A mechanistic kinetic model of cobalt–hydrogen electrochemical competition for the cobalt removal process in zinc hydrometallurgical was proposed. In addition, to overcome the parameter estimation difficulties arising from the model nonlinearities and the lack of information on the possible value ranges of parameters to be estimated, a constrained guided parameter estimation scheme was derived based on model equations and experimental data. The proposed model and the parameter estimation scheme have two advantages: (i) The model reflected for the first time the mechanism of the electrochemical competition between cobalt and hydrogen ions in the process of cobalt removal in zinc hydrometallurgy; (ii) The proposed constrained parameter estimation scheme did not depend on the information of the possible value ranges of parameters to be estimated; (iii) the constraint conditions provided in that scheme directly linked the experimental phenomenon metrics to the model parameters thereby providing deeper insights into the model parameters for model users. Numerical experiments showed that the proposed constrained parameter estimation algorithm significantly improved the estimation efficiency. Meanwhile, the proposed cobalt–hydrogen electrochemical competition model allowed for accurate simulation of the impact of hydrogen ions on cobalt removal rate as well as simulation of the trend of hydrogen ion concentration, which would be helpful for the actual cobalt removal process in zinc hydrometallurgy.


2021 ◽  
Vol 200 ◽  
pp. 105523
Author(s):  
Jiahui Wu ◽  
Liyuan Chai ◽  
Zhang Lin ◽  
Yangjin Wei ◽  
Meiqing Shi ◽  
...  

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 255
Author(s):  
Željko Kamberović ◽  
Nataša Gajić ◽  
Marija Korać ◽  
Sanja Jevtić ◽  
Miroslav Sokić ◽  
...  

By-products from zinc hydrometallurgy are classified as hazardous waste with strong leaching toxicities. Even though numerous research papers are dedicated to valorizing valuable metals in it, the primary management route is still disposal or partial reuse, such as the Waelz process. Presented experimental research investigates possibilities of sulfidization and further processing as a technologically sustainable route for valuable metals valorization from non-standard jarosite-PbAg sludge. The comprehensive thermodynamic analysis was done by HSC Chemistry®, through optimizing process parameters, i.e., temperature, sulfur addition, and selection of possible additives. Technological possibility of magnetic separation, flotation, and smelting of sulfidized material was also investigated; the results were below the values that allow practical application, due to the obtained texture of sulfidized jarosite, which does not allow the liberation of minerals. Smelting tests were performed on sulfidized jarosite with sulfur and without and with carbon as additive. By smelting sulfidized jarosite-PbAg sludge with added carbon in sulfidization stage at 1375 °C, obtained products were matte, slag, raw lead, and dust in which base, critical, and slag forming components were valorized. Valuable metals were concentrated in smelting products so as to enable further processing, which also could be interesting in the case of treatment of complex, polymetallic, and refractory primary materials, which represent a significant contribution to the circular economy.


2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Qianqian Wang ◽  
Minan Tang ◽  
Aimin An ◽  
Jiawei Lu ◽  
Yingying Zhao

<p style='text-indent:20px;'>Impurity removal is a momentous part of zinc hydrometallurgy process, and the quality of products and the stability of the whole process are affected directly by its control effect. The application of dynamic model is of great significance to the prediction of key indexes and the optimization of process control. In this paper, considering the complex coupling relationship of stage II purification process, a hybrid modeling method of mechanism modeling and parameter identification modeling was proposed on the basis of not changing the actual production process of lead-zinc smeltery. Firstly, the overall nonlinear dynamic mechanism model was established, and then the deviation between the theoretical value and the actual detected outlet ion concentration was taken as the objective function to establish the parameter identification optimization model. Since the built model is nonlinear, it may pose implementation problems. On the premise of deriving the gradient vector and Hessian matrix of the objective function with respect to the parameter vector, an optimization algorithm based on the steepest descent method and Newton method is proposed. Finally, using the historical production data of a lead-zinc smeltery in China, the model parameters were accurately inversed. An intensive simulation validation and analysis of the dynamic characteristics about the whole model shows the accuracy and the potential of the model, also in the perspective of practical implementation, which provides the basis for the optimal control of system output and the guidance for the optimal control of zinc powder addition.</p>


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