Nano-crystal glass-ceramics obtained from high alumina coal fly ash

Glass has been obtained by melting high alumina coal fly ash with fluxing additives. A thermal treatment was employed to convert the obtained glass into nano-crystal glass-ceramics. X-ray diffraction (XRD) patterns show that the main crystalline phases in both the glass-ceramics are anorthite (CaAl₂Si₂O₈) and wollastonite (CaSiO₃). The crystals are homogeneously dispersed within the parent glass. The average crystal size is below 200 nm. Physical and mechanical properties, such as density, thermal expansion coefficient, hardness, and bending strength, of the glass have been examined and the corresponding microstructures are discussed. The results demonstrate that the glass-ceramics have potential for a wide range of construction application.