Softening–Melting Behaviors of a MgO-SiO 2 -FeO Slag System on a Coke Bed

MgO is crucial for improving the softening–melting properties of pellets. By considering primary slags of magnesium pellets with high FeO and SiO 2 and moderate MgO contents, the effect of MgO/SiO 2 and FeO contents on the softening–melting behaviors of a MgO-SiO 2 -FeO slag system were studied. Relevant mechanisms were clarified using FactSage 7.0, XRD, and EPMA. By increasing the MgO/SiO 2 ratio from 0.3 to 0.9, the softening and melting temperatures of the slag increased by approximately 30°C. As the FeO content increased from 5% to 20%, the softening and melting temperatures of the slag decreased from 1368°C to 1271°C and 1395°C to 1342°C, respectively. The MgO/SiO 2 and FeO contents had little effect on the permeation temperature. Increasing the MgO/SiO 2 ratio improved the softening and melting temperatures of slag; however, increasing the FeO content decreased these temperatures owing to the substitution effect of Mg 2+ on Fe 2+ .