For better prevention of spontaneous fire in gobs affected by water immersion,variation on the microstructure and spontaneous combustion characteristics of Bulianta and Xiqu coal before and after long-term water immersion were investigated by detection techniques such as DSC,FTIR,XRD etc.Results showed that after 30-90 d immersion the activation energy de-creased 1.73-7.94 kJ/mol,and the heat release rate of coal samples in the process of low temperature oxidation were increased.And the absorption peaks of —CH2—,—OH,C—O etc.changed significantly.Besides,after long-term water immersion,mineral elements Si,Na,Ca,Fe,S etc.gathered on coal surface.Meanwhile,SiO2 content in coal was sharply reduced,which resulted in the treated coal swelled and broken continuously.Micropores (＞10 nm) also enlarged 4.61％-17.35％ in treated coal,which increased the oxygen diffusion rate.Due to the tensile strength of treated coal dropped to 0.192-0.495 MPa,block coal can more easily break into fine coal with different particle sizes,which increased the risk of spontaneous fire in goaf.In comparison,after water immersion,the change of self ignite characteristics in Bulianta coal is stronger than that in Xiqu coal,which could be attributed to the differences in the minerals composition and content of coal.%为了更好地防治水浸采空区的自燃火灾,利用DSC,FFIR,XRD等手段研究长期水浸前后补连塔烟煤与西曲烟煤的微观结构及自燃特性变化.发现经过30～90 d的水浸后,煤样在低温氧化过程中的活化能降低1.73 ～7.94 kJ/mol,且放热量增大,煤中—CH2-,—OH,C—O等活性结构吸收峰变化显著.此外,水浸后煤中SiO2含量大幅降低,煤表面Si,Na,Ca,Fe,S等元素富集,矿物质的析出致使煤体膨胀、破碎,大于10 nm的孔隙增加4.61％～17.35％,提高了煤中氧扩散速率;同时,由于水浸后煤的抗拉强度最低降至0.192 ～0.495 MPa,完整的块煤更容易破碎,加剧了采空区自燃风险.煤中矿物组分与含量的差异导致水浸后补连塔与西曲煤自燃特性变化的幅度也有所不同.
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