Thermal kinetics analysis of coal-gangue selected from Inner Mongolia in China

Abstract

Thermal behavior and kinetics analysis of coal-gangue sample selected from Inner Mongolia Autonomous Region in China were investigated by using thermogravimetry–derivative thermogravimetry, X-ray diffraction (XRD) analysis, and Fourier transform infrared (FT-IR) spectroscopy. The mineralogy of coal-gangue was mainly determined as kaolinite, quartz, and boehmite. The XRD and FT-IR results showed that the structure change in coal-gangue with the temperature increased. The structure parameters of the microcrystal carbon in coal-gangue sample, including interlayer spacing (d₀₀₂), average lateral sizes (L_a), stacking heights (L_c), and aromaticity (f_a), were calculated based on XRD data. With the increase in temperature, the values of d₀₀₂ and L_a decreased from 3.982 and 0.223 to 3.373 and 0.198 nm, respectively; however, the values of L_c and f_a increased from 0.111 and 0.633 to 0.156 and 0.852 nm, respectively. The average activation energy of coal-gangue was 102.66 and 103.73 kJ mol⁻¹, respectively, based on the Coats–Redfern and Flynn–Wall–Ozawa method.