Research of thermal destruction dynamics of coal particles in oxidizing medium with copper nitrate

Oxidation of brown coal containing 5% by weight of (Cu(NO₃)₂) initiation additive has been studied. The experiment was conducted using thermogravimetric analysis at a heating rate of 2.5°C/min up to a maximum temperature of 600°C in air. Based on DTA results, the oxidation characteristics were analytically evaluated. It has been discovered that addition of (Cu(NO₃)₂) initiation agent leads to a significant decrease of initial temperature of oxidation, which serves to shift the reaction to the low-temperature region. The effect of the initiation additive also manifested in significant reduction of sample residence time within sublimation of volatile compounds. Mass-spectrometric analysis has revealed the presence of NO_x (intense peak at 180°C) in oxidation products of the modified sample, which is explained by decomposition of copper nitrate. SEM results for the coal partially oxidized in the muffle furnace indicate significant change of surface and internal structure of the modified sample particles.