Study on the Influence of Intrinsic and Associated Pyrite on Spontaneous Combustion of Anthracite

The anthracite in Yangquan mining area contains intrinsic pyrite, and there is a considerable content of associated pyrite in the coal seam, which are easy to cause coal spontaneous combustion and seriously restricts the mine safety. In order to study the influence of intrinsic pyrite and associated pyrite on coal spontaneous combustion, the different contents of intrinsic pyrite in coal were removed by physical flotation and the associated pyrite was added to desulfurized coal. The synchronous thermal analysis and temperature-programmed chromatography were used to determine the difference of two kinds of pyrite on coal spontaneous combustion. The results suggested that with the increase of intrinsic pyrite content in coal, the characteristic temperature of coal decreases, the weight gain, the heat release increases and the release of SO2 increase, and the index gas production and activation energy also show an increasing trend. When the associated pyrite is added to the coal with the lowest intrinsic pyrite content (WK15-4), the weight, heat release and index gas release intensity also show an increasing trend, while the characteristic temperature decreases. The comparison shows that both AP and intrinsic pyrite of coal can promote coal spontaneous combustion, but the ability of AP to promote coal spontaneous combustion is stronger than that of intrinsic pyrite.