Isothermal Phase Diagram of CaO-SiO2-Nb2O5-5 wt.% Fe2O3-TiO2 System at 1100 °C

The phase diagram of the CaO-SiO₂-Nb₂O₅-Fe₂O₃-TiO₂ slag system has important significance for guiding the recycling and utilization processes of metallurgical slags containing niobium and titanium. In this paper, high-temperature equilibrium experiments were conducted at 1100 °C in air atmosphere to investigate the phase equilibria of the CaO-SiO₂-Nb₂O₅-Fe₂O₃-TiO₂ slag system. According to the experimental results, the liquidus surfaces of the liquid + CaTiO₃ and liquid + SiO₂ equilibrium coexistence regions in the CaO-SiO₂-Nb₂O₅-5wt.% Fe₂O₃-TiO₂ system at 1100 °C in air atmosphere were determined using interpolation and function fitting methods. Finally, the 1100 °C isothermal phase diagrams of the CaO-SiO₂-Nb₂O₅-5 wt.% Fe₂O₃-TiO₂ system were plotted. The composition range of liquid phase region was determined, and the positional relationships of the seven other equilibrium coexistence regions were illustrated.