Thermal stability of ammonium nitrate in high-temperature coal seam

Abstract

In order to investigate safety of blasting process in high-temperature coal seam, thermal decomposition characteristic of ammonium nitrate (AN) with coal was studied. The characteristic of HTCS was investigated firstly. The results found that organic materials presented in HTCS. TG–DSC results found that the notable exothermic reaction of AN with coal took place. And large amount of residue was found, which showed little amount of coal took part in thermal decomposition reaction. The activation energy results showed the coal was higher than AN. Isothermal experiments showed that AN with coal thermal decomposition is at about 135 °C. RSFTIR experiments found organic materials induced AN reaction at very low temperature. And NO3 − was found in molten AN. TG–MS experiments found that AN with coal thermal decomposition began at 146 °C. The essence of HTCS reaction was reaction between organic materials and HNO3. With temperature elevated, the organic materials were oxidized by HNO3, which caused exothermic and gave rise to premature and misfire in blasting process. The study results have significant implication in the understanding of safety of civil explosives in HTCS.