Research carried out on the interactions between PbSO4 and ZnS, using mixtures with variable molar ratios of PbSO4:ZnS, showed that the process starts at 803 K. It was found that a few reactions occur at the same time, including transformation of zinc sulfide into its oxide and PbS formation; the secondary lead sulfate containing the sulfur from ZnS also appears. The PbS is derived primarily from PbSO4, and some of it contains the sulfur from ZnS.