Influence of different content of FeS2 on spontaneous combustion characteristics of coal

To ascertain the influence of different FeS2 contents on the microstructure and spontaneous combustion characteristics of coal, TG-DSC-FTIR, chromatographic oxygen absorption experiments and scanning electron microscopy were used to study the variation characteristics of parameters such as the TG-DSC curve, characteristic temperature, functional group, activation energy and surface structure of coal samples with different FeS2 contents. The results showed that the addition of FeS2 had little effect on the surface morphology, and the fine particles on the surface of the coal decreased after the temperature rose. As the sulfur content increased, the water loss temperature (T1) gradually decreased, the oxygen absorption temperature (T2) first decreased and then increased, the ignition temperature (T3) increased overall, and the extreme point appeared at a 3% sulfur content. Aromatic hydrocarbons, aliphatic hydrocarbons and oxygen-containing functional groups in the coal structure first increased, then decreased and then increased during the oxidation process. The peak chromatographic value of oxygen absorption appeared at a 3% sulfur content, an increase of 15.33%; the promotion rate was the largest at 9.94%, and the activation energy reached a minimum. Therefore, when the sulfur content was 3%, the promotion effect on spontaneous coal combustion was the greatest. The research results have important theoretical and practical significance for the prevention and utilization of spontaneous coal combustion.