In view of the lack of phase equilibria data of vanadium-bearing oxide system and the desirability of
them for design or optimisation of vanadium extraction process, the phase equilibria relationships of
V2O3-FeO-SiO2-CaO(15 mass per cent) system were determined experimentally and then an
isothermal section phase diagram of this system was constructed. Totally, 81 samples of different
composition were equilibrated at 1623 K for 48 hours in iron crucible under Ar atmosphere. The
equilibrated samples were quenched quickly in cold water, and then the phase constituents of all the
samples were identified by X-ray diffraction (XRD) combined with electron probe microanalysis
(EPMA) measurements.