Experimental Research on Resistance Characteristics of Hypophosphite to Coal Spontaneous Combustion

To explore the inhibition characteristics of hypophosphate inhibitors on coal spontaneous combustion oxidation, raw coal sample and the coal samples treaded by sodium hypophosphate and aluminum hypophosphate with the concentrations of 15%, 17% and 20% were prepared. The effect of hypophosphite inhibitors on CO emission during coal spontaneous combustion was analyzed by the oxidation experiment of programed heating. The optimum concentration of each phosphate inhibitor was determined by calculating the inhibition rate. The thermogravimetric and exothermic characteristics of coal spontaneous combustion oxidation were analyzed by synchronous thermal analysis. The results show that the hypophosphite inhibitors can inhibit the formation of CO during coal spontaneous combustion, and the optimum inhibition concentration is 20%. Hypophosphate inhibitors can significantly increase the characteristic temperature points of coal, such as the ignition temperature and the burnout temperature. Among them, the inhibitory effect of sodium hypophosphite inhibitor is better than that of aluminum hypophosphite inhibitor. In addition, sodium hypophosphite inhibitor can observably increase the initial heat release temperature and maximum heat release power temperature, and reduce the maximum heat release power and total heat release of coal spontaneous combustion.