Abstract
In this study, as part of developing a green recycling process of spent lead-acid battery that can avoid both smelting and electrowinning, leaching agent citric acid and other additives (such as sodium citrate and hydrogen peroxide) in aqueous media were reacted with spent lead-acid battery paste. PbO, PbO2 and PbSO4, which are the three main components in a spent lead-acid battery paste, were leached to form lead citrate precursor which was crystallized and then separated from the solution. Reaction between spent lead-acid battery paste and citric acid based reagents at the pH of 3~4, yielded lead citrate, Pb(C6H6O7)ˇH2O, which was characterized by XRD, SEM and FT-IR analysis. The optimal conditions for leaching spent lead-acid battery paste at room temperature were found to be: 2.19 mol L-1 of C6H8O7ˇH2O, 1.29 mol L-1 of Na3C6H5O7ˇ2H2O solution, 1/5 as the starting ratio of spent lead-acid battery paste to water (S/L) and reaction time of 8 h. The results showed that up to 98 % of lead from spent lead-acid battery paste was converted to the lead citrate under the optimal conditions.