Effect of SiO2/Al2O3 ratio on sintering behavior, crystallization behavior and properties of diopside-anorthite glass-ceramics

Diopside-anorthite glass-ceramics were prepared by direct sintering with extracted titanium slag (ETS), coal fly ash (CFA) and quartz sand (SA), the effect of sintering temperature (1120–1180°C) and the SiO2/Al2O3 ratio (1.85–2.63) on the phase transitions, physical characteristics and microstructure was examined by adding CFA (28.5–40%) and SA (0–12.5%) to ETS (60%). The results revealed that the sintering temperature and the ratio of SiO2/Al2O3 have a substantial impact on the sintering and processing properties of glass-ceramics. When the sintering temperature is lower than 1160°C, the sample sintering is incomplete, and when the sintering temperature is higher than 1170°C, the sample is prone to over-sintering and foaming. With the increase of SiO2/Al2O3 ratio, anorthite content increases, while diopside content decreases. When SiO2/Al2O3 ratio is 2.13, 1160°C sintering 1 h, the better performance of diopside-anorthite-based glass-ceramics was prepared. The linear shrinkage, bulk density, water absorption and bending strength of the obtained glass-ceramics are 9.96%, 2.52 g/cm3, 0.943%, and 96.1 MPa, respectively. The results show that the prepared glass-ceramics are industrially applicable.