STUDY OF PbSO sub(4) SOLUBILISATION IN NaOH SOLUTION, FOR THE TREATMENT OF OXIDE-SULPHATE PASTES OBTAINED FROM DISMEMBERED LEAD-ACID BATTERIES

The paste from dismemberment of discarded lead-acid batteries contains mostly lead sulphate and lead oxide. Both can be solubilized with high yielding sodium hydroxide, the result being sodium with lead that can ultimately be exposed to electrolysis. A small quantity of insolubilized paste, which remains in the form of solid residue, is recycled to a classification phase. Using this procedure, no residue is to be generated during the hydrometallurgical process. The method of sodium hydroxide solution solubilisation belongs to a recent initiative of obtaining lead, while attempting a double win: the control for the pollution of the environment and the processing of other secondary resources, such as the volatile dusts resulted from the metallurgical extraction of lead from primary resources. This work presents the experimental results regarding the solubility of the lead sulphate. The parameters considered were the Na OH concentration, the S:L ratio, and the temperature under the working circumstances: concentrations 2; 4; 6 and 8M NaOH, S:L, ratios of 1:10, 1:30, 1:50, at temperatures 40[degrees]C, 60[degrees]C and 80[degrees]C.