To reveal the influence mechanism of the drying process of immersed coal on the spontaneous combustion characteristics and the change rule of the spontaneous combustion process, in this research, we measured the pore structure of coal with low-field nuclear magnetic resonance, the mass change during coal oxidation with thermogravimetry, and the change of the functional groups with Fourier transform infrared spectroscopy. Additionally, we conducted a temperature-programmed spontaneous combustion

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... experiment with coal samples with different treatments to study the oxygen consumption rate and heat release. The results showed that the pore volume content of the pores with pore sizes of less than 100 nm was significantly reduced. The diameter range of 100–1000 nm was gradually generated after 8 h of coal drying, and the proportion of large pores and cracks larger than 1000 nm increased significantly during the drying process of the immersed coal. The oxygen consumption rate and the heat release rate were significantly affected by the degree of dryness and the temperature of coal samples in the temperature-programmed process. The turning point temperature was 140°C. Below the turning point temperature, the raw coal had the fastest oxygen consumption and maximum heat release. When the coal temperature was higher than 140°C, the oxygen consumption rate and the heat release rate of the coal sample that was dried for 24 h were higher than those for the raw coal, followed by the samples that were dried for 8 h and dried for 48 h.