The application of zinc calcine as a neutralizing agent for the goethite process in zinc hydrometallurgy

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.

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Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process

Minerals ◽

10.3390/min11060586 ◽

2021 ◽

Vol 11 (6) ◽

pp. 586

Author(s):

Yunpeng Du ◽

Xiong Tong ◽

Xian Xie ◽

Wenjie Zhang ◽

Hanxu Yang ◽

...

Keyword(s):

Hazardous Waste ◽

Acid Leaching ◽

Copper Recovery ◽

Water Leaching ◽

Flotation Process ◽

Metal Levels ◽

Valuable Metals ◽

Leaching Experiments ◽

Zinc Hydrometallurgy ◽

Poor Stability

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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Effects of temperature and neutralizing agent on lactic acid production by Rhizopus sp. fermentation

10.1063/5.0051959 ◽

2021 ◽

Author(s):

Whiny Erliana ◽

Tri Widjaja ◽

Tectona Indah ◽

Daryl Susilo ◽

Annisa Dewi

Keyword(s):

Lactic Acid ◽

Acid Production ◽

Lactic Acid Production ◽

Neutralizing Agent ◽

Effects Of Temperature ◽

Rhizopus Sp

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PHEX neutralizing agent inhibits dentin formation in mouse tooth germ

Tissue and Cell ◽

10.1016/j.tice.2010.12.008 ◽

2011 ◽

Vol 43 (2) ◽

pp. 125-130 ◽

Cited By ~ 2

Author(s):

Hongbing Lv ◽

Sheng Fu ◽

Gancha Wu ◽

Fuhua Yan

Keyword(s):

Tooth Germ ◽

Neutralizing Agent ◽

Dentin Formation

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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 ◽

10.1515/ijcre-2021-0077 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Jihao Guo ◽

Hongao Xu ◽

Bo Li ◽

Yonggang Wei ◽

Hua Wang

Keyword(s):

Hydrogen Peroxide ◽

Acid Concentration ◽

Acid Leaching ◽

Metal Extraction ◽

Agitation Rate ◽

Leaching Kinetics ◽

Solid Ratio ◽

Zinc Hydrometallurgy ◽

Kinetics Of ◽

Leaching Efficiency

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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