Direct Electrolytic Refining of Lead Acid Battery Sludge

Abstract

The direct electrorefining of anode particles obtained from lead acid battery sludge to produce electrolytic lead powder without application of the conventional leaching process is the aim of this work. To create this target, exhausted lead acid batteries were crushed to smaller particles and separated from the internal and external plastic covers and fed into a titanium nets basket which acts as the anode in the electrolytic cell. Two pure lead permanent cathode sheets together with the Ti-anode basket were immersed in an acidified leach liquor electrolyte containing 1.24 wt% HCl acid and 2.2 wt% Pb ions. Different parameters were investigated, such as addition of NaCl to the electrolyte, electrolyte stirring rate, electrolysis mode (electrorefining or electrowinning), and presence of suspended PbCl2 particles in the electrolyte. Electrolytic lead powders with a dispersed shape with about 0.7 % Ti were obtained. The obtained results indicated that the electrorefining technique is better than electrowinning with both cathodic current efficiency and powder productivity, while the energy required for the electrowinning process is lower. The electrorefining process was carried out with cathodic current efficiency up to 64.69 % and specific electrical energy demand in the range from 2.598 to 3.827 kWh/kg Pb with powder productivity up to 2.5 g/A.h.