Thermal activation and structural succession of coal gangue in southern Sichuan, China

Coal gangue is rich in kaolin clay minerals, which can be used as raw materials for the preparation of adsorbents and intermediates of adsorbents, and is important for the high added value utilization of coal gangue. In this study, coal gangue from southern Sichuan, China, was activated and characterized by calcination at 100~900 °C, and the succession laws of the phase, microstructure and physical properties under thermal activation conditions were studied. Results showed that the content of active hydroxyl groups in the thermally activated coal gangue was the highest, and the chemical reaction activity was highest at 800 °C for 2 h. The pore structure of thermally activated coal gangue is primarily mesoporous, which nearly disappears at 900 ℃. The specific surface area of thermally activated coal gangue is highest at 600 ℃ and lowest at 900 ℃. The results of this study provide a reference for the preparation of adsorbents and adsorbent intermediates from coal gangue.