Study On Lead Electrodeposition Based On Ion Exchange Membrane And Its Mechanism

As a common metal element in industry and life,lead has abundant reserves in the earth’s crust.China’s lead ore output has always been at the forefront of the world,but the lead resource recovery rate can only reach about 30%.In the long run,the sustainable use of lead resources presents challenges.The lead-acid battery industry,as the main force of lead resource consumption,is the most important field of lead resource recycling in China.Pyrometallurgy is mature but the recovery channel is not yet perfect.A large number of waste lead-acid batteries flow into illegal recycling channels,causing resources and the environment problems.Wet recycling equipment is flexible and has easier structure,but it has not been widely used due to technical deficiencies in the energy consumption,lead recovery rate,and waste liquid treatment of electrolysis.In this study,lead methanesulfonate was used as the electrolyte and ion exchange membranes were introduced into the electrolysis device to explore and optimize the electrolysis operation parameters.The aim was to improve the current electrolysis process of wet recycling process of lead,so that its advantages can be exerted.Help to break through the difficulties faced by lead recycling and promote the green and sustainable development of lead resources.The research mainly focuses on the following points:（1）The development and testing of electrolytic refining equipment in the wet recycling process of lead.This study introduces an anion exchange membrane in the traditional electrolytic refining lead equipment,which can avoid the loss of lead at the anode and recover acid in the anode chamber,improve lead recovery rate and achieve resource reuse;（2）Based on the diaphragm electrorefining device,explore the effects of lead methanesulfonate concentration,current density and additive dosage on the quality of electrodeposited lead and search for the best experimental operating conditions;（3）Combine the lead crystal growth theory to analyze and explain the experimental phenomena,discuss the deposition morphology of lead from the perspective of crystal growth,and realize the prediction of the experimental results to guide the actual operation.The study found that lead methanesulfonate as an electrolyte has the advantages of high solubility and environmental friendliness.Butyl acetate as an electrodeposition additive has a good improvement on the electrodeposition of lead;through experimental exploration,it was found that the control experimental conditions were:lead methanesulfonate concentration was 0.4 mol·L^-1,butyl acetate addition amount was 2.0 g·L^-1,and current density was 20 m A·cm^-2.The deposition quality is the best,and can guarantee higher current efficiency and lower mass specific energy consumption.Combined with the theoretical analysis of lead electrodeposition,it is found that the addition of butyl acetate will have a certain effect on the electrodeposition behavior of lead.The essential reason for the adjustment of experimental factors on the morphology of lead electrodeposition is that changes in these factors can change the state of the overpotential or the diffusion layer on the cathode surface.This article discusses the electrodeposition of lead from two aspects:experimental phenomena and theoretical analysis,which provides a reference for the optimization of the electrolytic refining process of lead.