Effect of Ce2O3 and CaO/Al2O3 on the Phase, Melting Temperature and Viscosity of CaO-Al2O3-10 Mass% SiO2 Based Slags

The melting temperature and viscosity of CaO-Al2O3-10 mass% SiO2 based slag system with various concentrations of Ce2O3 have been studied using the melting point detector and the rotating crucible viscometer. And X-ray diffraction analysis has been used for phase identification. The results show that cerium is stable in Ce3+ state existing mainly as CeAlO3 and Ce4.67(SiO4)3O phase in slags and CeAlO3 phase appears in green color. The melting temperature gently decreases with Ce2O3 additions in 1.57 of CaO/Al2O3. Moreover, the melting temperature increases first and then decreases with the increasing of CaO/Al2O3 from 1.17 to 1.52 at 4.47 mass% Ce2O3. In addition, at 1.57 of CaO/Al2O3, the viscosity increases at the beginning and then decreases with the increasing Ce2O3 content from 4.39 to 11.48 mass%. Furthermore, at 4.47 mass% Ce2O3, the viscosity decreases at the first and then increases with the increasing CaO/Al2O3 from 1.17 to 1.52. Meanwhile, from the slopes of the Arrhenius relationship for viscosity, the activation energy range of viscous flow is from 179.07 to 433.70 kJ/mol. On the basis of these results, slag composition of 45.64 mass% CaO-39.02 mass% Al2O3-10.73 mass% SiO2-3.83 mass% Ce2O3 is melting temperature of 1361 °C and viscosity of 0.398 Pa·s (1500 °C), which has superiority and is more suitable for the actual refining process