Integrated utilization of coal gangue for synthesis of β-Sialon multiphase ceramic materials

To realize the effective utilization of the industrial waste coal gangue, in this study, beta-SiAlON multiphase ceramic material was successfully prepared using coal gangue as main raw material. The thermodynamic analysis of beta-SiAlON synthesis was firstly performed. We also investigated the performance of the synthetic materials under different conditions. We found that an increase in thermal treatment temperature promotes the formation of the beta-SiAlON phase. The optimal holding time was determined to be 4 h at 1500 degrees C, under which the flexural and compressive strengths of the material were 10.1 MPa and 24.7 MPa, respectively. Meanwhile, the shrinkage and porosity value were 13.1% and 22.3%, respectively. At last, the reaction direction of impurity elements and the migration of heavy metals in the synthesis process were also mentioned.