Abstract: Lead paste generated from spent lead acid battery has been converted to lead carbonate using NH4HCO3+NH3·H2O as the desulfurization conversion agents.Effects of the dosage of conversion reagents，liquid-solid ratio，conversion temperature，and conversion time on desulfurization rate and lead recovery were investigated，and the optimal conditions were confirmed.The results showed that the desulfurization rate of lead paste was up to 99.5% under the conditions that the dosage of NH4HCO3+NH3·H2O was 2 times of theoretical value，liquid-solid mass ratio was 5∶1，conversion temperature was at room temperature， and conversion time was 2 h.Under different experimental conditions，the change of the content of lead in desulfurized paste was not obvious，all about 30%（mass fraction），far from the content of lead in the starting lead paste which was 71.87%，so the recovery rate of lead was less than 50%.Meanwhile，the desulfurized paste and the starting lead paste were analyzed by XRD，and the results also showed that the desulfurization rate of lead paste could reach more than 99%.

Key words: spent lead acid battery；carbonatation；NH4HCO3+NH3·, H2O