Process for recovering lead from used lead-acid batteries

Abstract

The invention relates to a process for recovering lead from spent lead-acid batteries by hydrometallurgy comprising the following steps: (i) mixing and stirring a paste obtained from spent lead-acid batteries containing mainly lead sulfate, lead oxide and lead powder into an organic acid solution to convert the lead oxides and lead ions into lead complexes; (ii) Add H2O2 solution while stirring the reaction mixture, maintaining the reaction to dissolve all the lead powder and convert all the lead cans into lead(II) complex; (iii) Add alkali metal citrate salts to the reaction mixture until the pH is between 4.5 and 5.5 to convert the lead(II) complexes into lead(II) citrate complexes; and (iv) Filter to obtain a solution containing lead(II) citrate complex; in which: - organic acids are selected from the group including lactic acid, acetic acid, oxalic acid; - The temperature throughout the entire process is maintained between 30°C and 80°C; - The concentration of the H2O3 solution is between 5 and 15% by weight.