Optimization of heat treatment of glass-ceramics made from blast furnace slag

CaO-MgO-Al2O3-SiO2 glass-ceramics with diopside as the main crystalline phase were prepared by melting blast furnace slag obtained from Baotou Iron and Steel Company. The effect of heat treatment on the crystallization behavior of glass-ceramics, containing a large proportion of melted blast furnace slag, was studied by means of differential thermal analysis and scanning electron microscopy. The optimum heat-treatment regime was obtained by orthogonal experimental results for glass-ceramics in which blast furnace slag comprised 70% of the composition and 1% Cr2O3 and 4% TiO2 were used as nucleating agents. The nucleation temperature was 750 degrees C for 2.5 h and the crystallization temperature was 930 degrees C for 1 h. Under this regime, the performance of the glass-ceramic was better than that of other groups in the orthogonal experiment.