This study aims to characterize the whole reaction process of (i) emulsion explosive matrix and sulfide ores, and (ii) ammonium nitrate and pyrite by the thermodynamics analysis method. A series of experiments were carried out at atmospheric pressure from 25 °C to 350 °C at four heating rates (3, 5, 10, and 15 K/min) and the Coats–Redfern method was applied to calculate the apparent activation energy of samples at different heating rates. The results show that the thermogravimetric (TG) curve of sulfide ores and emulsion explosive matrix can be divided into four stages: the water evaporation stage, the dynamic balance stage, the thermal decomposition stage, and the extinguishment stage. However, the thermal decomposition process of ammonium nitrate and pyrite can be divided into the dynamic balance stage, the thermal decomposition stage, and the burnout stage. The ignition temperature (T0) and maximum peak temperature (Tm) of the samples increased with the heating rate, but the shape of the TG/DTG (Derivative Thermogravimetric) curve was not affected. The results show that the reaction process of sulfide ores and emulsion explosive matrix is similar to the reaction process of pyrite and ammonium nitrate. The thermal stability of emulsion explosive matrix decreases when sulfide ores are added. By contrast, when pyrite is added, the thermal stability of the ammonium nitrate decreases more significantly.