| The technology of zinc hydrometallurgy has made progress continuously since it was put into production in industry at the early 20th century, and more than 80% total output of zinc is using this technology. Zinc hydrometallurgy has shortcomings of high energy consumption in the electrowinning process. Therefore,it's necessary to speed up the process energy-saving and environment protection technology and actively promote the changing of equipment and technological transformation with a view energy saving and emissions reduction, so we must use the new equipment and technology which is helpful to saving energy and protecting environment, enhance the holistic utilization of resources and promote the clearer production and develop circular economy and the industry of energy saving and environmental protection technology. It's essential to develop high technology industry energetically and achieve the optimization and upgrading of the industrial structure and independent innovation.The dissertation regards ZnSO4-H2SO4 system as the object of study, and research the technology of zinc electrowinning. The main contents can be summarized as follows:1.The study of parameters optimizing and energy consumption in ZnSO4-H2SO4 system:After the technology conditions which influenced energy consumption in electrowinning process were analyzed synthetically, some contents were researched as follows:(1) the effect of the zinc sulfate and sulfuric acid concentration on the electrolyte density at different temperatures; (2) the effect of the zinc sulfate and sulfuric acid concentration on the electrical conductivity at different temperatures; (3) the effect of the zinc sulfate and sulfuric acid concentration on the cell voltage in electrowinning process; (4) the effect of the zinc sulfate and sulfuric acid concentration on the current efficiency in electrowinning process; (5) the effect of the zinc sulfate and sulfuric acid concentration on the energy consumption during electrowinning process. Regression analysis method was used to analyze the experimental date and the regression equations were deduced variational laws among each parameter based on test.. These equations can help us to analyze some practical questions of zinc electrowinning, and provide definite guidance for the use of status of improving electrical power and optimizing technical condition in hydrometallurgy of zinc.2.The study of effect of impurities on zinc electrowinning in ZnSO4-H2SO4 system:There are more than 20 kinds of impurities in zinc sulphate electrolyte, and Co, Ni, As, Sb, Ge are the main factors effecting the zinc product surface quality and current efficiency. We adopted the electrochemical methods to research the effects of Co, Ni, As, Sb, Ge impurities on zinc electrowinning in the experimental study. Through investigating above mentioned five impurities effects of transient and steady cathodic polarization curves from one dimension (on impurity) to five dimensions in different concentrations and temperatures. Through measuring data from polarization curv found e and calculating dynamic parameters according to Tafel and Butel-Volmer formulas we the electrons transferring number. It found that the concentration of Co>6mg/L, Ni>14mg/L, As>6mg/L, Sb≥1mg/L, and Ge≥lmg/L had appreciable impact, Co and Ni had minimal impact, Sb and Ge has more impact on zinc electrowinning. The three-stage purifying technology was put forward through experiments, which could actualize deeply deprivated.3. The study of effect of additives on the zinc electrowinning in ZnSO4-H2SO4 system:This text testing over ten reagents such as glutin, DBS and thiourea, which influenced on surface quality of zinc as additives. Optimize some additives which are good effect to we had more thorough research in mechanism of action through photos. The experiments revealed that glutin was absolutely necessarily in deposition process of zinc, compare single additive; compounded additive could make more ideal effect. Ideal additive could enhancement surface quality of zinc,increase current efficiency,economy cost obviously, additive could also depression return-dissolution phenomenon, had some value in industry.4. The study of effect of magnesium on zinc electrowinning:Mg2+which was more negative than zinc was not removed when the low concentration of Mg2+ had no effect on electrowinning process. But magnesium salt increased continuously in the hydrometallurgy system, it makes the density, viscosity and resistivity of the electrowinning solution increased when it reaches saturated concentration, which leaded to the resistance, the current efficiency and the energy consumption increasing. It was studied that the effects of Mg2+concentration on the density, viscosity and resistivity of electrowinning solution, and the current efficiency and energy consumption at different temperatures in this paper. And some experimental data were provided, which could be useful for hydrometallurgy factory and the correlation technological personnel.5. The study of the reaction kinetics model about zinc electrowinning with magnesium ion:the reaction kinetics model about zinc electrowinning in the zinc current sulfate solution with magnesium was presented in this paper. Density functional theory based on first principle and CASTEP quantization tools were used to demonstrate above model in theory.Some specific measures of energy conservation in zinc electrowinning were put forward through studing technology. The contents are listed as follows:(1)selecting optimized parameter system. When experimental condutions were certain(the current density was 527A/m2, temperature was 40℃, the dosage of glutin was 10mg/L, the period was 24h), the Zn2+concentration was 52g/L, the H2SO4 concentration was 134g/L, the energy consumption was the minimum value, which was 2961.344kW·h/tzinc.(2) Carrying through three-stage deeply purifying. Comparing with traditional purifying technology, the current efficiency was observed to increase 5%, and energy consumption to decrease 150kW-h/t using deeply purifying solution after electrowinning 48h. (3) Adding combined additives into electrolyte. It was thiourea and glutin, the dosage of thiourea was 20mg/L, the dosage of glutin was 15mg/L. after adding combined additives, the current efficiency was observed to increase 3%, and energy consumption to decrease 150kW·h/t, and the effect of combined additives was more evident when the period of electrowinning was more than 48h.The main innovation points:(1) The effects of the temperature, H2SO4 and Zn2+concentration on electrolyte density, electrical conductivity, the cell voltage and the current efficiency were studied, and the regression equation about the effect of electrowinning parameters on energy consumption was built up, which has directive significance for the actual production of zinc electrowinning.(2) Three-stage deeply purifying technology was put forward through systematically studying the effects of impurities on zinc electrowinning. Using this purifying technology the energy consumption could be decreased 150kWh/t. and the mechanism of hydrogen evolution about zinc electrowinning was researched.(3) The combined additives were obtained through studying the effects of single additive on zinc electrowinning, which were thiourea and glutin. Adding combined additives the energy consumption could be decreased 150kWh/t in zinc electrowinning.(4) Magnesium on the effect of zinc electrowinning was first researched, and got the reaction mechanism of zinc sulphate electrolyte with magnesium.
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