Recovery of lead in form of high purity lead carbonates from spent lead batteries incl. electrode paste

摘要

Wet process of low environmental impact recovers the lead content of an electrode slime and/or of lead minerals in the valuable form of high purity-lead carbonates that are convertible to highly pure lead oxide by heat treatment in oven at relatively low temperature, perfectly suited for making active electrode pastes of new batteries or other uses. The process basically comprises the following steps: a) adding sulphuric acid to a different acid leach suspension of the starting impure material for converting all dissolved lead compounds to insoluble lead sulphate; b) separating the solid phase constituted by lead sulphate and undissolved impurities from the acid leach solution; c) selectively dissolving lead sulphate contained in said separated solid phase in an aqueous solution of a lead solubilizing compound comprising preferably sodium acetate; d) separating the solution containing dissolved lead sulphate from the solid phase residue including undissolved impurities; e) adding to the separated solution of lead sulphate a carbonate of the same cation of said dissolving compound for forming insoluble lead carbonate and/or and lead oxycarbonate and a dissolved sulphate of the same cation; f) separating the precipitated carbonate and/or oxycarbonate of lead from the dissolving solution now containing also sulphate of the cation of said solubilizing compound.