New Process And Engineering Research Of Perchloric Crude Lead Electrolysis Refining

Lead-acid batteries have become an important chemical power source for automobiles,electric vehicles,UPS and solar cell due to their mature technology,stable electrochemical performance,and low price,which has greatly promoted the growth of refined lead consumption.Crude lead refining mainly consists of two refining processes:fire refining and electrolytic refining.Because of the complicated process of pyrometallurgical smelting process,low vertical recovery,low precious metal recovery rate,high energy consumption and other deficiencies,the wet refining process becomes the preferred process.The existing wet electrolysis process is the Betts method in which fluosilicic acid is used as the electrolyte.This method not only has the problem of high energy consumption in electrolysis,but also heats the electrolysis process and volatilizes and decomposes toxic fluorine compounds HF and SiF4,the workshop environment and the atmosphere cause severe fluorine pollution.In view of the problems of crude lead wet electrolysis,this article uses dilute perchloric acid solution as a stable non-oxidizing electrolyte,and established an 9.1 m3 electrolyzer in Anyang Minshan Group to study onengineering process of new technology for fluoride-free energy saving crude lead electrolysis.Around the crude lead electrorefining process,the main contents of this work are as follows:(1)The effects of the combined additives on the cathodic electrodeposition process of lead were studied by means of constant current electrolysis,potentiodynamic scanning,alternating current impedance and Tafel,The results showed that additive A additive D and additive C can be used as a joint additive,lead deposition can get a good effect.(2)Electrochemical methods were used to study the effect of main impurities in the electrolyte on the cathodic electrodeposition process.The results of the study show that the electrolyzers with perchloric acid as the electrolyte have a lower voltage and impurities do not accumulate to harmful levels;At the current density 400 A m-2,anode slime 0.4 g L-1,Cu2+ 0.003 g L-1,Bi3+ 0.002 g L-1,Fe3+ 1.5 g L-1,and Sb3+ 0.3 g L-1 will not cause great harm to the electrolytic cell voltage,the purity and morphology of the deposited lead;For the problem of excessive impurities in the early stage of re-production,the electrolyte solution can be used to purify the electrolyte below the safety line.(3)Over 200 days of continuous electrolysis in three phases of 200 L,500 L to 9 m3,The results showed that at the range of electrolysis conditions HClO4 240-250 g L-1,Pb2+ 85-95 g L-1,electrolysis temperature 35-50 ?,electrolyte circulation rate 20-45 L min-1 and current density 170-350 A m-2;With a current density of 170 A m-2,the new process energy consumption of per ton lead is only 48 kWh and the current efficiency is more than 99%,compared with Betts method,it can save energy by 60%and the purity of deposited lead can reach 99.9991%;When the current density is 300 A m-2,the per ton lead energy consumption is only 90 kWh,and the current efficiency is greater than 97%;Crude lead electrorefining in the perchloric acid system can achieve the goals of energy saving,production increase,and environmental protection and achieve both economic and social benefits.