Effect of glass content on sintering kinetics, microstructure and mechanical properties of glass-ceramics from coal fly ash and waste glass

Abstract In this paper, coal fly ash and waste glass were used as raw materials to prepare CaO-Al2O3-SiO2 system glass-ceramics by direct sintering. The effects of glass content on the kinetics, phase, microstructure and mechanical properties of glass-ceramics were studied by means of liquid phase sintering formula, X-ray diffraction, scanning electron microscope and the corresponding property tests. The results showed that as glass content increased, the activation energy of glass-ceramics first decreased and then increased due to the precipitation of tridymite and augite, and the surface of glass-ceramics gradually became smooth and dense. The water absorption and total porosity of the glass-ceramics were decreased with increase of glass content，while the flexural strength and bulk density were increased. When the amount of waste glass added is 40% and the sintering temperature is 1100 °C, the glass-ceramics have dense surface and high bending strength, which is suitable for high-strength building glass-ceramics. The experimental results of this paper provide a basis for direct sintering industrial production of glass-ceramics.