A green and cost-effective process for recovery of high purity a-PbO from spent lead acid batteries

Herein, we propose a green, cost-effective and short-loop route for recovering high-purity alpha-lead oxide (alpha-PbO) from spent lead-acid batteries. This newly proposed route consists of leaching, carbonation and thermal decomposition processes. In the leaching process, the lead sulfate (PbSO4) from spend lead paste was reacted with conjugated solution of ammonium sulfate-ammonia ((NH4)(2)SO4NH3) to form a soluble complex. The dissolved PbSO4 in the conjugated solution was converted into lead carbonate (PbCO3) precipitate via absorption of carbon dioxide (CO2). Afterwards, the high-purity alpha-PbO was obtained by thermal decomposition of PbCO3. Results show that the leaching rate of PbSO4 from lead paste reaches up to 99.8 +/- 0.15%, the recovery rate of lead is 99.85% and the purity of the obtained alpha-PbO is as high as 99.992%, indicating the recovered alpha-PbO has high purity. As well, the recovered alpha-PbO shows a better electrochemical activity than the conventional Shimadzu ball-milling method. Beside of recovering high-purity alpha-PbO, the used raw materials of conjugated solution and the intermediate product of CO2 could be collected and utilized in the next batch. Therefore, the present work develops a new green and economic route to solve the recovery problems of high purity alpha-PbO from spent lead-acid batteries.