LEACHING OF SPENT BATTERIES POWDER WITH SODIUM CARBONATE AND CARBON DIOXIDE

Abstract

The processing of lead from scrap lead-acid batteries by pyrometallurgical route is generally accompanied byemissions of sulphur dioxide and high amount of slags. Therefore, lead is entrapped in the slags as xNa2S.yFeS.zPbSwhich makes the slag unsuitable to be disposed off as environmental friendly product. To overcome thesedifficulties, a sodium carbonate leaching process was investigated. The sample used for this study was a pastepowder from spent batteries. The reactions of sized battery paste powder with sodium carbonate media werestudied over a broad range of experimental conditions. Carbon dioxide gas was bubbled through sodium carbonatesolution at 20°C to form sodium hydrogen carbonate which enhanced the transformation of by-products,hydrocerrusite (Pb3(CO3)2(OH)2) and sodium lead carbonate (NaPb2(CO3)2OH) into PbCO3 which reduced theemissions of sulphur dioxide and high amount of slags . Results were discussed from kinetic behavior aspect,especially: leaching curves, stoichiometry of the reaction and X-ray diffraction analysis of the reaction products.Under these conditions, lead carbonate recovery of 68 % was obtained in less than about 40 minutes at roomtemperature.