Some aspects of electrowinning of lead for treatment of scrap lead acid batteries

Disposal of lead acid batteries has assumed importance with constant growth of automobile industries. Paste fraction of the battery waste is always an area of environmental concern. Pyrometallurgical operation currently employed causes emission of oxides of lead and particulate lead causing atmospheric pollution. Electrolytic route is investigated as an alternative. Anodic deposition of PbO2 is a major problem identified in the electrowinning of lead. Addition of certain soluble compounds of phosphorous or arsenic is found to inhibit PbO2 effectively. Levelling of lead deposit is another aspect of investigation. Addition of levelling agent and grain refiner in proper proportion avoids dendritic growth. Over potential measurement is found to be useful in monitoring the concentration of additives in the electrolyte during electrowinning of lead.