Study on combustion characteristics and mechanism of coal gangue under isothermal conditions

In this study, a vertical combustion test system is designed. The combustion characteristics of coal gangue under different environmental atmospheres are analyzed. Luminous parameters such as average gray value and image entropy were used to evaluate the intensity of combustion. Moreover, the combustion residue of coal gangue is also analyzed. Coal gangue combustion in furnace is mainly diffusion combustion. The combustion reaction process is mainly restricted by the mass transfer rate. At an oxygen concentration of 40 vol%, the image entropy decreases significantly, indicating higher burning brightness. Dehydroxylation reaction (removal of hydroxyl group in a reaction) and combustion reaction of combustible organic polymer occur simultaneously. Aluminosilicate minerals (minerals containing Al, Si and O) such as kaolinite contained in coal gangue can inhibit the combustion reaction to a certain extent.