Metallic lead recovery from exhausted lead-acid storage batteries - involves treating milled electrode paste with aqueous saline, reducing solubilised lead II ions with iron, reducing lead IV oxide and recovering salts for reuse

摘要

The recovery of lead from exhausted lead-acid storage batteries comprises (i) removing the H2SO4 solution, the coating element, electrode separators and metal parts (i.e. grids, connectors and poles) and (ii) milling the remaining electrode paste to obtain an extremely fine powder. The powder is then (a) treated with aqueous saline solution of pH 0-8 to solubilise Pb (II) sulphate and oxide but not Pb (IV) oxide, (b) the Pb (II) ions are reduced to metallic Pb by treatment with Fe metal (preferably in slight stoichiometric excess), (c) the Pb (IV) oxide is reduced and (d) the salts used in (a) are recovered by eliminating the iron sulphate that has formed.