Investigation on activation technology of self-heating decarbonization of coal gangue by a sintering process

Coal gangue is a solid waste discharged in coal mining and dressing process. Large-scale decarbonization and activation treatment are key steps toward massive and efficient utilization of coal gangue. In this paper, a new process for the preparation of a cement admixture from coal gangue by effectively utilizing its calorific value was developed. The mineral composition, crystal structure, and microstructure of the sintered products obtained under different sintering conditions were investigated using XRD, FTIR, SEM and mechanical property analysis to reveal the activation mechanism of coal gangue. The blended cement containing 30% activated coal gangue prepared by adding 3% coal and no return fine exhibited the best mechanical properties. Furthermore, the mechanical properties of the cement containing 30% activated coal gangue prepared without coal and return fine were adequate, reaching a productivity of 0.96 t/(m 2 ·h). The results show that the thermal activation of exhaust sintering can greatly improve the cementitious activity of coal gangue. Finally, the applied technology is promising for industrial application.