The glass-ceramics of CaO-Al2O3-SiO2system were prepared by sintering using lead-zinc tailings. Orthogonal experiment was carried out to optimize the ratio of lead-zinc tailings, chemical composition of basic-glass and other chemical materials in the system. Crystallization heat treatment conditions were confirmed by the differential thermal analysis (DTA) curve of glass aggregate. Crystalline phase, crystal morphology and mechanical property of the glass-ceramics samples were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), hardness and bending strength test. The results indicated that the optimized ratio of the samples was lead-zinc tailings 25%, quartz 46.63%, calcite 21.05%, Al2O310.19% and nucleating agent TiO21%. The optimized crystallization heat treatment was that basic glass was first heated to 800 °C at 10 °C/min, then 800°C-900 °C at 5 °C/min and held still at 900 °C for 2 h. After that, the basic glass was heated to 1230 °C at 1-1.5 °C/min,held for 1h. At last, the glass-ceramics was obtained after the cooling-down of the system. The main crystalline phase of microcrystal glass-ceramics are diopside. The hardness and bending strength were 9.14 GPa and 213.6 MPa, respectively. The glass-ceramics had excellent chemical durability in acid and alkali solution, with weight losses of 0.17% and 0.68%, respectively.
Effect of crystallization heat treatment on the microstructure of niobium-doped fluorapatite glass-ceramics
