Dissolution of pastes in lead-acid battery recycling plants

The dissolution of the active materials of lead-acid batteries in fluoboric electrolyte has been studied. The use of redox couples such as Ti3+/Ti4+ is proposed for an efficient and quick dissolution of lead and lead dioxide mixtures. For PbO2 and Pb electrodeposited on platinum electrodes the rate of dissolution in HBF4 (200 g dm−3) containing Ti ions (0.3m) corresponds to a current density of 400 A cm−2 and 160 A cm−2, respectively. Dissolved oxygen has a marked influence on lead dissolution acting as an oxidizer of Ti3+ to Ti4+. It has also been shown that the Fe2+/Fe3+ couple can be used, although with lower benefits. For industrial applications, a concentration of Ti ions of about 0.051m and the use of a counter-current electrolyte flow in the electrolysis cell can advantageously accomplish the leaching process of pastes and slimes in a batteries recycling plant.