Sintering Process and Characteristics of Glass-Ceramics from Coal Fly Ash

In this study, glass-ceramics was prepared with coal fly ash by direct sintering to solve the problem of resource utilization of coal fly ash. The effects of the sintering temperature on volume density, water absorption, and open and closed porosity from 1000 to 1200 °C were investigated. The sintering process of glass-ceramics was also investigated by XRD and SEM. The data indicate that the sintering process was accomplished by dissolving the solid amorphous phases, hematite, and portion quartz of coal fly ash to form anorthite. During the process, the open porosity of the material gradually tended to closure. The glass-ceramics fired at 1180 °C for 30 min featured good strengths, with compressive strength of 122 MP and bending strength of 34 MP. The obtained relatively low density of 1.94 g cm−3 and moderate water absorption of about 1% would make these materials suitable for lightweight construction tiles. Besides, owing to the abundance of coal fly ash produced from thermal power plants, the present technology should be suitable for large-scale manufacturing of glass-ceramics, with economic benefits and possible solutions to environmental and wastes disposal concerns.