Study on Pyrolysis and Oxidation Characteristics of Coal Gangue Based on TGA-DSC

Abstract

Coal gangue spontaneous combustion has caused serious environmental and ecological problems. To investigate the reaction kinetic parameters of the gangue and the exothermic characteristics of the spontaneous combustion of the influence of the law, this study employs the thermogravimetric method to explore the characteristic parameters of the pyrolysis and oxidative combustion process of the gangue from the perspective of thermodynamics, and, at the same time, using the differential scanning calorimetry (DSC) on the exothermic effect of the gangue to explore the gangue to obtain the gangue and the original coal TG/DTG/DSC curves to be compared and from the perspective of thermodynamics. The change rule and potential parameters in the pyrolysis and oxidative combustion process of coal gangue (CG) were analyzed, the oxidation kinetic properties of CG were studied, and the reaction mechanism of oxidative spontaneous combustion of CG was further explained. The results show that the TG/DTG/DSC curves of CG in different gas atmospheres will have significant differences in all stages, and in the process of pyrolysis and oxidative combustion, the thermogravimetric curves of CG and those of the original coal show a consistent trend, except for the large difference in peak amplitude in different stages; in different gas atmospheres, as the rate of warming increases, the TG/DTG/DSC curves of the gangue are tilted toward the hightemperature region, they are inclined to the high-temperature region with the increase of the heating rate, and the phenomenon of "hysteresis" of characteristic temperature occurs. The research results provide a theoretical basis for the construction of a spontaneous combustion early warning system based on the fine division of gangue pyrolysis and oxidation combustion stages.