Phase diagram of the SiO ₂ ‐FeO‐V ₂ O ₃ system at 1623 K (1350°C)

Abstract Owing to the shortage of phase equilibrium data for vanadium‐containing oxide systems, the SiO 2 ‐FeO‐V 2 O 3 system at 1623 K under iron‐saturated conditions was investigated using isothermal equilibration and quenching methods. Phase compositions of quenched samples were analyzed by X‐ray diffraction and electron probe microanalysis, which revealed nine phase regions involving combinations of liquid, Fe 3‐x V x O 4 , SiO 2 , Fe t O, and (V 2 O 3 ) s.s. . An isothermal phase diagram was constructed and compared with calculations from FactSage, and significant differences were found: First, the experimental liquid‐phase region was considerably smaller; Secondly, the solubility range of V in the Fe 3‐x V x O 4 phase was smaller (1.47 ≤ x ≤ 2.00) than the calculated value (1.23 ≤ x ≤ 2.00); Thirdly, the solubility limit of V 2 O 3 in Fe t O was 9.6 mass pct., higher than the calculated value of 8.0 mass pct. These results provide reliable experimental data for improving thermodynamic databases, refining phase diagrams, and supporting more accurate modeling of high‐temperature vanadium oxide systems in pyrometallurgical applications.