Improve The Current Efficiency Of Zinc Electrolysis Process System

Zinc hydrometallurgy is mainly composed of the roasting,the gas to assit sulphation,the leaching,clarified solution,electrodeposit,the casting。After 1980's,the The proportion of zinc produced by this method is more than 80%of the whole zinc industry in the world.But,the high consumption of electricity is a big disadvantage of this method.In the whole process of the roasting and leaching and electrolytic of the fine zinc sulfide to the obtainment the the zinc,the power consumption is about 50×10⁹J /(t·Zn). The power consumption of the process of electrodeposit account for 80%of the whole.So reducing the power consumption of the electrodeposit working procedure a important mean for saving the energy and power and promoting the economic benefit,First,we make kinetic analyze of the electrodeposit.This electrode process is a integration of all reactions that occur on the surface of the electrode under a electric potential that different from the electrocal equilibrium potential,It is a very complicate process.It is the electrochemical reaction itself that have a great influence on the electrodeposit.secendly,with thermodynamics analyzing,Here is the principle of the electrodeposit:in the purified ZnSO4 aqueous solution,the Pb-Ag alloy acts as anode,the pure aluminum sheet acts as cathode,with the direct current, the Zn²⁺in the solution discharge and separate out zinc,the OH in the solution discharge and produce O2.Try to find the main reason of the low level of the current efficiecy, we make a thoroughly test of the of the following parameters of the present electroanalysis system:(1):the concentration of Mg²⁺(2)the content of F^-,Cl^-(3)the content of sulphation in the electroly solution(4)the management of the cell(5)the zinc of the cathode conglutinate the(6)the process of the cathode zinc sheet stripping(7)the process of the cathode zinc overflowing the solution(8)cathode plateAfter a detailed inspection of the process of electrolytic zinc production of the YUNNAN LUOPING AND ELECTRICITY CO LTD,we make a detailed discussion about how to promote the current efficiency and make some improvement experiments in this articleThe following scheme can be adopted:(1)control the concentration of Mg²⁺(2)removing the F^-,Cl^-.(3)change the pole plates(4)improve the managementWith these methods,we can keep the concentration of the Mg²⁺under 25g/L,F^- under 80mg/L,Cl^- under 160 mg/L,then we can get a current efficiency above 85%.