Preparation and Properties of CaO-Al₂O₃-SiO₂ Glass-Ceramics Prepared from Waste Materials by Direct Sintering

Taking waste glass, fly ash and calcia as raw materials, CaO-Al2O3-SiO2 (CAS) glass-ceramics were prepared from by the direct sintering method, and effects of CaO content and sintering temperature on sintering properties, crystalline composition, microstructure and bending strength of CAS glass-ceramics were studied. The results show that bulk density of the glass-ceramics initially increased and then decreased with the increase of CaO content and sintering temperature, and high CaO adding amount and sintering temperature could promote formating column-shaped wollastonite phase. The bending strength of CAS glass-ceramics exhibited the same tendency as bulk density. The CAS glass-ceramic prepared by 18wt% CaO showed maximum bulk density of 2.26 g·cm-3 after it was sintered at 1 100 ℃ for 2 h, its cystalline phase was a single wollastonite structure with a crystallinity degree of 50.7 % and maximum bending strength of 81.5 MPa.