Preparation mechanism of ceramic material with solid waste of coal gangue and red mud

Coal gangue and red mud, are solid waste found in the central and western parts of China, and are very difficult to be recovered. It is an effective way to realize high-value utilization of solid waste by using them to prepare ceramics. In this paper, the coal gangue and red mud from the Hejin area of Shanxi province were used as raw materials to prepare the whole-solid waste ceramic samples. The effects of raw material ratio, sintering temperature and sintering time on the physical properties and microstructure of the samples were studied by XRD, SEM and alkali metal leaching tests. The results showed that the raw material ratio could affect the crystal phase and pore structure of the samples. The optimum conditions were the raw material ratio between coal gangue and red mud of 1∶1, the sintering temperature of 1 200 ℃ and the sintering time of 15 min. Under these conditions, the water absorption rate of the samples was 0.15%, and their flexural strength was 90.40 MPa. The structure was dense and the main mineral phases were anorthite and hauyne. The alkali metals in the red mud were effectively solidified. Compared with the samples before sintering, the consolidation rates of sodium and potassium ions reached 97.17% and 96.76%, respectively. The main occurrence mineral phases of alkali metal ions were anorthite and hauyne.