Phase Diagram of CaO-Al₂O₃-VO_x Slag System Under Reducing Atmosphere

The phase diagram information of the CaO-Al₂O₃-VO_x system is of significant importance for the direct alloying study of vanadium (V) during the smelting process of V-containing alloy steel, as well as for subsequent process optimization. This study has utilized the high-temperature phase equilibrium experimental method, combined with scanning electron microscope–energy dispersive spectrometer (SEM–EDS), electron probe micro-analysis (EPMA) and X-ray photoelectron spectroscopy (XPS) detection techniques, to research the phase equilibrium of the CaO-Al₂O₃-VO_x system under argon (Ar) atmosphere at 1400°C. This study reveals that the phase diagram of CaO-Al₂O₃-VO_x system, under the specified conditions, comprises 4 three-phase regions, 7 two-phase regions, and a liquid phase region. This study has plotted the CaO-Al₂O₃-V₂O₅-VO₂ three-dimensional phase diagram and represented the phase equilibrium in CaO-Al₂O₃-V₂O₅, CaO-Al₂O₃-VO₂, CaO-Al₂O₃-VO_2.335, and Ca-Al-V systems. At the same time, the reliability of each projected phase diagram was quantitatively assessed.