Study on inhibition performance of coal spontaneous combustion by sodium phosphate

In order to explore the inhibiting effect of sodium phosphate inhibitors on spontaneous combustion oxidation of coal, taking gas coal as the experimental coal sample, two types of sodium phosphate (NaH₂PO₄ and Na₃PO₄) were selected to prepare inhibitors. By synchronous thermal analysis experiment and programmed temperature-rise oxidation experiment, the effects of sodium phosphate on the characteristics of thermal weight loss, thermal release and gas phase during coal spontaneous combustion were analyzed.The results show that Na₃PO₄ no longer has resistance when the spontaneous combustion of coal reaches the pyrolysis temperature; NaH₂PO₄ significantly improves the critical temperature, dry crack temperature and ignition temperature of coal spontaneous combustion, in addition, NaH₂PO₄ not only effectively increases the initial exothermic temperature and maximum exothermic temperature, but also reduces the maximum exothermic power and heat release of coal spontaneous combustion; NaH₂PO₄ improves the initial generation temperature of CO, CO₂ and hydrocarbon gases during coal spontaneous combustion and weakens its release intensity, its resistance rate reaches 65.4%; compared with Na₃PO₄ inhibitor, NaH₂PO₄ inhibitor has better inhibiting effect and plays an inhibitory role in the whole process of coal spontaneous combustion.