Phase composition and liquidus temperatures of the CaO–SiO2–MgO-13 wt%Al2O3–TiO2 system in reduction conditions

Abstract

Effects of TiO2, binary basicity and MgO content on the liquidus temperatures of TiO2–CaO–SiO2–MgO–Al2O3 slags were experimentally studied in equilibrium with carbon. The experimental techniques include high temperature equilibration, quenching and Electron Probe X-ray Microanalysis (EPMA). It was found that the major primary phase in the composition range investigated is M3O5 (M = Ti, Mg, Al). The liquidus temperatures increase with increasing TiO2 and MgO contents, whereas decrease with increasing CaO/SiO2 mass ratio. The experimentally determined liquidus temperatures are much higher than the predicted ones by FactSage and the primary phases between the experiment results and predictions are also different. The mole fractions of Al2TiO5 and Ti3O5 in the M3O5 phase decrease, but MgTi2O5 increases with increasing MgO content and CaO/SiO2 in the samples. Moreover, the proportions of Al2TiO5 and MgTi2O5 in the M3O5 phase decrease, while Ti3O5 proportion in the M3O5 phase increases with increasing the reaction time. The mole ratio of Ti3+/Ti4+ in the M3O5 phase decreases with MgO content and CaO/SiO2 mass ratio in the samples but increases with increasing reaction time.