Thermodynamic calculation and experimental investigation on the dissociation of lead sulfide under vacuum

Lead sulfide is the main raw material employed to produce lead. And it is believed to be a very stable substance. The dissociation pathway of lead sulfide is believed to be 2PbS = 2Pb(l)+S2, and its initial dissociation temperature at 10 Pa is believed about 1273 K, and there is no report that it could directed dissociate into lead and sulfur. In this work, we theoretically calculated the stability of lead sulfide at the pressure of 10 Pa, and experimentally investigated the dissociation product of lead sulfide. The first part of this article investigated the dissociation pathways of lead sulfide based on thermodynamic calculation. The second part studies the dissociation as well as volatilization product using X-ray diffraction, ICP-AES and SED. The result indicated we could obtain lead from the direct dissociation of lead sulfide, and the dissociation pathway is 2PbS (g) = 2Pb(l)+S2. At 1153 K, the decomposition rate is 39.23%, and the purity of lead is 99.9%.