Vitrification and Crystallization Behavior of CaO-SiO2-MgO-Al2O3-Fe2O3-Cr2O3 System

The effect of basicity and Cr2O3 content on vitrification of the CaO-MgO-SiO2-Al2O3-Fe2O3-Cr2O3 system during a melt-quenched process and the crystallization and mineralogical evolution of the obtained glasses were investigated. X-ray diffraction (XRD) analysis of the quenched samples indicated that lower basicity (B = 0.8 and 1.0) and lower Cr2O3 concentration (< 4 wt pct) were favorable for glass formation. B = 1.25 and 1.5 samples were crystallized much easier, with most of the Cr captured in the spinel structure. Differential scanning calorimetry measurements revealed that the glass transition and crystallization temperatures both increased upon increasing the heating rate from 5 K to 20 K (°C)/min. In addition, compared with the samples without Cr2O3, the crystallization activation energy of those with Cr2O3 were lower for the same basicity. For glassy samples heated above 1228 K (955 °C), XRD and scanning electron microscopy characterizations suggested that diopside and wollastonite were the main precipitated phases for the samples with B = 0.8, whereas akermanite and wollastonite were the main phases for samples with B = 1.0.