Novel Lead Battery Recycling Process Combining Pyrometallurgical Anode Preparation and Electrorefining

Lead acid batteries are processed mainly by using pyrometallurgical operations with problems related to SO2 evolution. Many efforts have been devoted to solving this concern. In this work, where only the anode preparation was a pyrometallurgical process, this problem has been overcome by limiting the process temperature. Several tests have been carried out in order to determine the starting mix composition that allows to reduce the process temperature and then SO2 emissions. Three different anode types were cast and tested. Independently on the anode type, the complex composition of the anode requires to design a special electrolytic cell composed by two different compartments. Preliminary electrorefining tests highlighted that the best results were obtainable by using the anode cast in a titanium holder that allowed to obtain high-purity lead, high anode durability, and low quantity of anodic mud. By using this anode, the specific energy consumption varied over the 0.04–0.17 kWh/kg range.