Phase equilibria relations in V2O5-rich part of the Fe2O3-TiO2-V2O5 system at 1200°C related to converter vanadium-bearing slag

The efficient recycling of vanadium from converter vanadium-bearing slag is of great significance for sustainable development and circular economy. The key to developing novel processes and improving traditional routes lies in the thermodynamic data. In this study, the equilibrium phase relations for the Fe2O3-TiO2-V2O5 system at 1200 °C in air were investigated using a high temperature equilibrium-quenching technique, followed by analysis using Scanning Electron Microscopy-Energy Dispersive and X-ray Photoelectron Spectroscopy. One liquid phase region, two two-phase regions (liquid-rutile and liquid-ferropseudobrookite), and one three-phase region (liquid-rutile-ferropseudobrookite) were determined. The variation of TiO2 and V2O5 concentrations with Fe2O3 concentration was examined for rutile and ferropseudobrookite solid solutions. However, upon further comparison with the predictions made by FactSage 8.1, significant discrepancies were identified. This highlights the need for greater attention to be given to updating the current thermodynamic database related to vanadium-bearing slag systems.