Investigation of combustion characteristics and kinetics of coal gangue with different feedstock properties by thermogravimetric analysis

• Combustion characteristics of coal gangue are investigated by thermogravimetric analysis.
• Kinetic parameters are obtained by distributed activation energy model.
• Combustion condition and mineral decomposition exhibit different characteristic DTG curves.
• Ignition temperature is affected by volatile content and oxygen adsorption behavior jointly.
• Activation energy for the combustion of coal gangue is in the range of 117–300 kJ/mol.

The combustion behavior of eleven coal gangue was investigated by thermogravimetric analysis (TGA). The effects of feedstock properties (combustible matter and mineral matter) on combustion characteristics of coal gangue were analyzed. The kinetic parameters were obtained based on experimental results by distributed activation energy model (DAEM). The results show that the ignition temperature of coal gangue is affected by volatile content and oxygen adsorption behavior jointly. In the main weight loss stage, combustion reaction of combustible matter and dehydroxylation reaction of mineral matter proceeded simultaneously. Combustion conditions of volatile matter and fixed carbon, as well as, decomposition of kaolinite, illite and calcite exhibited different characteristic DTG curves. The activation energy for the combustion of coal gangue was in the range of 117–300 kJ/mol. Feedstock properties affected the change of activation energy with conversion values. The maximum relative errors between calculated and experimental results by DAEM model were 0.2–0.5%.