Melting Properties and Phase Composition Transformation of Ti-Bearing Electric Furnace Slags in CaO–SiO₂–MgO–Al₂O₃–50%TiO₂ System

This study aims to experimentally investigate the influence of several key factors, including basicity, Al₂O₃ content, TiO₂ content, SiO₂/Al₂O₃ ratio, and titanium reduction, on the melting properties of electric furnace slags containing titanium in the CaO–SiO₂–MgO–Al₂O₃–50%TiO₂ system. The findings revealed that the melting temperature decreased with an increase in the CaO/SiO₂ ratio, Al₂O₃ content, and SiO₂/Al₂O₃ ratio, while it increased with higher TiO₂ content. To achieve a low melting temperature for the slags and an appropriate phase composition for titanium extraction, it is advisable to maintain a low CaO/SiO₂ ratio within the range of 0.6–0.7, and an Al₂O₃ content of 13% is recommended. Higher TiO₂ content is associated with elevated liquidus temperatures, while conversely, the SiO₂/Al₂O₃ ratio exhibits an inverse relationship. Efforts were made to limit the titanium reduction during smelting to a maximum of 0.4. Anosovite (MgTi₂O₅), CaAl₂Si₂O₈, Mg(Al, Ti)₂O₄, spinel (MgAl₂O₄), augite (Ca(Mg, Fe, Al) (Al, Si)₂O₆) and Ca₁₂Al₁₄O₃₃ were the primary phases in titanium slag. The calculated viscosity results align with the trends observed in the melting property results. Furthermore, the liquidus temperatures were obtained through FactSage aligns with the pattern observed in the melting temperature. These findings will serve as a valuable technical foundation to support the development of the direct reduction smelting process for the comprehensive utilization of vanadium titanomagnetite.