Phase equilibria of TiO2–SiO2–CaO–10%Al2O3-7.5%MgO at 1773 K and effects of MgO on the distribution of phase fields

Abstract

The 1773 K phase diagram of the TiO2–SiO2–CaO-10 wt%Al2O3-7.5 wt%MgO system was constructed experimentally using the quenching method, focusing on the composition range of high TiO2 content. The obtained isothermal section contains four phase fields: the liquid phase field, the primary phase field of pseudo-brookite, the primary phase field of perovskite, and the liquid + perovskite + pseudo-brookite phase field. The pseudo-brookite particle precipitated in its primary phase field is more suitable for the efficient selective enrichment and separation of titanium resources. The increase of MgO from 5 % to 7.5 % in the TiO2–CaO–SiO2-10 wt%Al2O3–MgO system leads to a decrease of the liquidus temperature and an expansion of the liquid + pseudo-brookite + perovskite phase field. The increase of MgO promotes the enrichment of TiO2 into the pseudo-brookite phase and reduces the TiO2 level in the glass phase.