Combustion properties of coal gangue using thermogravimetry-Fourier transform infrared spectroscopy

This study investigated the combustion properties of coal gangue (CG) from the Gongwusu coal mine in northern China. Three CG samples collected from various parts of the spontaneous combustion gangue dump were evaluated using a proximate analyzer, thermogravimetry, and Fourier transform infrared spectroscopy. The results revealed that the total mass losses of the three samples were 15.5%, 30.3%, and 19.42%, which were consistent with the volatile and fixed carbon contents (Vad + FCad). The calculated combustion performance indices (Sn) of CG for the three samples were 6.01 × 10−10, 29.42 × 10−10, and 15.65 × 10−10%2/(min2 K3). The Sn values increased with an augment of Vad + FCad/Aad. Sample 2 had a higher de-volatilization rate, burnout performance, and total mass loss, and it was easier to ignite during the spontaneous combustion process. The combustion performance of CG was more favorable when Vad + FCad was high and the ash content was low. In addition, the CG samples from the same mine area contained analogous hydroxyl, aliphatic, and oxygen functional groups, and aromatic compounds.