Effect of Steel Slag on Crystallization and Bending Strength of Glass Ceramics Based on Blast Furnace Slag

The glass ceramics based on steel slag and blast furnace slag presented light-khaki color to deep-brown color with increasing content of steel slag. The major crystalline phase is gehlenite (Ca2Al2SiO7) with minor akermanite phase (Ca2MgSi2O7) for all the samples. Decreasing Al2O3 and increasing Fe2O3 in the samples increased glass viscosity, and decreasing SiO2 decreased the amount of liquid phase. Both the above effects result in the increasing optimum sintering temperature. The grain size and amount of crystalline phase were increased with content of steel slag. The bending strength of the samples first increases with content of steel slag up to a maximum 90 MPa, then decreases. The bulk density of the samples decreases with increasing content of steel slag, from 2.76 g/cm(3) to 2.60 g/cm(3), owing to lower content of glass phase during sintering process. The samples exhibit good chemical resistance, and the weight loss values in alkali are lower than those in acid. Therefore, the glass ceramics based on steel slag and blast furnace slag may have great potential for applications as building decorative materials, and it provides a promising way for the utilization of steel slag.