Effect of temperature on the present forms of MgO in the reconstruction of steel slags

By varying reconstructed temperature of steel slag, present form, crystallizing conditions and lithofacies characteristics of MgO and RO were tested by XRD, SEM and lithofacies analyses. Contents of MgO and RO phase in other phases of steel slag were analyzed by phase separation. The results show that when the reconstructed temperature of steel slag increases, the content of gel minerals also increases, and the degree of crystallization comes nearer to completion. The existing state of MgO changed to solid solution state from the free state. When the reconstructed temperature of steel slag was at 1300 ºC, the contents of MgO solid dissolved in gel minerals (e.g., silicate and mesophase). However, at very high temperature, recrystallization occurred in the steel slag, and larger amounts of free MgO were generated, which could affect the strength of steel slag.