PbSO4 decomposition kinetic and phase transformation mechanism during lead waste recycling

PbSO4 is the main component of lead paste, lead smoke and other lead-containing solid wastes. It usually matches with the primary lead concentrate to co-smelt for lead extraction, mostly in the oxidation smelting stage. The lead waste quickly experiences different temperature and atmosphere fields from feeding the furnace to the completion of the reactions. This work investigated PbSO4 decomposition kinetic and phase transformation mechanism during lead waste pyrometallurgical recycling. The results show that the activation energy of the decomposition reaction of PbSO4 at 800 degree celsius similar to 1000 degree celsius in Ar atmosphere is 121.35 kJ/mol. The PbSO4 decomposition reaction in Ar and Air is a multi-step decomposition process, which may undergo PbSO4 -> PbO<middle dot>PbSO4 -> 2PbO<middle dot>PbSO4 -> 4PbO<middle dot>PbSO4 -> PbO. PbO is not generated through direct decomposition of PbSO4. The results are expected to provide guidance for the lead wastes co-smelting process to achieve a target PbSO4 decomposition product.