A study on the thermal decomposition of coal-derived pyrite

The thermal behavior of coal-derived pyrite as well as ferrous sulfide compound during heat treatments was investigated by temperature-programmed decomposition–mass spectrometer analysis (TPD–MS) and X-ray diffraction (XRD) measurements. An influence of atmosphere on pyrite and FeS decomposition and the interaction between pyrite and a coal-like environment were examined. The results showed that pyrite decomposition under inert atmosphere occurred in steps and the different transition states with Fe/S value were formed during heat treatments. The final solid state under helium contained only Fe(1−x)S phase. The presence of carbon support and hydrogen could promote pyrite transfer and change the sulfur evolution behavior during decomposition process. However, hydrogen was the principal factor which could determine the presence of iron phase in the final products.