The use of metal carbonates to intensify coal ignition and combustion is considered. To coal powder (<0.1 mm fraction), 5 wt admixtures of Na_2CO_3, K_2CO_3, CaCO_3, MgCO_3, and CuCO_3 are introduced, by a mechanical method. The oxidation, ignition, and combustion of the mixtures is studied by thermal analysis and high-speed video recording in a combustion chamber with an atmospheric temperature of 700°C. The metal carbonates tend to increase the reactivity of the coal, as indicated by the increase in oxidation rate (established by thermal analysis), the heat liberation (according to differential scanning calorimetry), and the shorter delay in ignition and combustion (according to video data). The carbonates also result in more complete coal combustion and decrease the emissions of gaseous CO and NO_x. In the later stages, combustion of the modified samples is accompanied by periodic microexplosions. The change in coal reactivity is greatest in the case of copper carbonate.
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