Equilibrium Phase Relationships of CaO-SiO2-TiO2 System with 5 wt% Cr2O3 Addition for Titania-Bearing Slag Recycling

It has been proved that Cr 2 O 3 is favorable to promote the crystallization of perovskite in the Selective Crystallization and Phase Separation (SCPS) process. However, the related thermodynamic data of equilibrium phase relations was quite limited. In the present work, the equilibrium phase relations of CaO-SiO 2 -TiO 2 system with the addition of 5 wt% Cr 2 O 3 were experimentally carried out using the high temperature equilibration-quenching technique followed by X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM–EDS), as well as thermodynamic calculation. More attention has been focused on the influence of 5 wt% Cr 2 O 3 addition on the liquid-perovskite two-phase coexisting region. The results indicated that the crystallization of perovskite was promoted by Cr 2 O 3 addition by expanding the primary phase of perovskite toward higher SiO 2 areas. Meanwhile, distinct discrepancies were found when the present experimental results were compared with the data from the literature and the isotherms calculated by FactSage, indicating that the present results are not only meaningful for the improvement of the SCPS process, but also important for the optimization of titania related oxide thermodynamic database. Graphical Abstract