Kinetics of the interaction of iron, copper, and nickel sulfides with a sodium nitrate-sodium carbonate mixture

The interaction of FeS2, Cu2S, and Ni3S2 with sodium nitrate and sodium carbonate between 573 and 973 K has been investigated by chemical analysis, X-ray diffraction, electron probe X-ray microanalysis, and thermal analysis. The kinetic limitations in these reactions are due to the formation of a passivating layer of reaction products on metal sulfide particles. The solid products of the reactions are sodium sulfate, Fe2O3, CuO, NiO, and copper metal.