Effect of TiO2 on crystallization kinetics, microstructure and properties of building glass-ceramics based on granite tailings

Abstract

The R2O-CaO-MgO-Al2O3-SiO2 building glass-ceramics based on granite tailings (56 wt%) were prepared by melt-cooling method followed by nucleating and crystallization. The nucleating agent TiO2 was added to the batches to investigate its effect on the crystallization, phases and microstructure of the glass-ceramics. The crystallization kinetics, microstructure, and physical- and chemical-properties of the baseline glasses/glass-ceramics were characterized by differential scanning calorimetry (DSC), scanning electron microscopy and Energy-dispersive X-ray spectroscopy (SEM-EDS), mechanical property and chemical resistance test. The results show that, for the baseline glasses containing TiO2 ≥ 3 wt%, the main phases of the glass-ceramics are hornblende and anorthite while nucleating at 730 °C for 2 h and crystallizing at 1030 °C for 2 h, fine grains and dense microstructure of the glass-ceramics are achieved, resulting in their good chemical resistance to the acid- and alkali-solution. Moreover, the bending strength and Vickers hardness of the glass-ceramics are higher than 200 MPa and 8.2 GPa respectively. These properties meet the national standards of glass-ceramics for building decoration (JC/T872-2000 and JC/T258-1993), thus the prepared glass-ceramics using 56 wt% of the granite tailings as raw material are potential building glass-ceramics for architectural decoration.