Vacuum decomposition thermodynamics and experiments of recycled lead carbonate from waste lead acid battery

Lead acid batteries have been widely used in different fields, so abundant waste lead acid battery was generated. Waste lead acid battery is regarded as a toxic material due to the metallic lead and the lead paste compounds. Once lead and its compounds enter the human body and the environment, which will cause serious threats. At present, the waste lead acid batteries are mainly recovered in the form of metal lead, which has many problems. Thus, this paper put forward a novel technology to recycle waste lead acid battery. Vacuum thermal decomposition was employed to treat recycled lead carbonate from waste lead acid battery. Thermodynamics analysis and experiments were finished from the reaction free energy of lead carbonate decomposition and vacuum furnace. The results showed that the recycled lead carbonate began to be decomposed when the temperature reached 250°C. Above 340°C, most of intermediate PbCO3•2PbO were converted to red α-PbO and then transformed to yellow β-PbO when the temperature was raised further to 460°C. Furthermore, the study provided the fundamental data for the preparation of α-PbO and β-PbO in vacuum, which also demonstrated a new way for the reuse of spent lead acid battery resource and an outlook of sustainable production.