A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pressure on the phase equilibria and liquidus in CaO-Al2O3 -FeOx system with the intermediate oxygen partial pressures of 10.13Pa and 1.01×10 -3 Pa.The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA (Scanning Electron Microscope/Electron Probe Micro-Analysis) and XRD (X-Ray Diffraction) .The phase equilibrium results include two cases,the two-phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13Pa or 1.01×10 -3 Pa.Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO Al2O3 and CaO2 Al2O3 were notable.With the decrease of oxygen partial pressure,the liquid area expands and the liquidus of CaO Al2O3 and CaO2 Al2O3 primary fields moves to the Al2O3-FeOxregion.On the other hand,the liquid area of CaO-Al2O3-FeO x system extends extremely to the high Al2O3 region with the temperature increasing from 1 400to 1 500℃,especially at lower oxygen partial pressure.The present experiment results are in good agreement with the calculated ones by FactSage.
