Crystallization behavior of glass ceramics prepared from the mixture of nickel slag, blast furnace slag and quartz sand

The purpose of this paper was to investigate the crystallization process of glass ceramics prepared from a mixture which was composed of nickel slag, blast furnace slag and a small amount of quartz sand. First, the parent glass of the mixture was prepared. Then, the glass ceramics were obtained by heat-treating for the parent glass. The crystallization behavior was studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). A large number of tiny spherical crystals were observed when the glass was heated up to 700 °C. Subsequently, the radial crystals were observed when the glass was heated up to 820 °C. By XRD analyzing, the spherical crystals and radial crystals were likely to be the crystals of diopside (CaMg(Si,Al,Fe)2O6) and hedenbergite (CaFe(Si,Al,Fe)2O6). The crystallization temperature was 860 °C and the final crystalline phases were identified to be diopside and hedenbergite. In addition, the activation energy of crystallization was evaluated by Kissinger method.