Comparison of the inhibition mechanisms of five types of inhibitors on spontaneous coal combustion

Five inhibitorsZn/Mg/Al-CO3 layered double hydroxides (LDHs), thermosensitive hydrogel (P(NIPA-co-SA)), diammonium phosphate ((NH4)(2)HPO4), sodium phosphate (Na3PO4), and magnesium chloride (MgCl2)commonly used to forestall the spontaneous combustion of anthracite and coke coal were investigated in this study, and the inhibition effects were quantified. According to the results of thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy, and kinetic analysis, Zn/Mg/Al-CO3-LDHs, P(NIPA-co-SA), and (NH4)(2)HPO4 all exert substantial inhibiting effects on anthracite and coke coal. Specifically, P(NIPA-co-SA) was altered during the liquid-to-gel phase, which isolated the oxygen from the coal surface and produced an endothermic reaction that decreased the environmental temperature; this reaction further inhibited spontaneous combustion. Conversely, MgCl2 promoted a combustion reaction and reduced the apparent activation energy of coal, increasing the risk of spontaneous combustion. This study provides a reference for selecting suitable inhibitors to prevent the spontaneous combustion of coal.