Phase Equilibria of SiO2-Ce2O3-CaO-25wt.% Al2O3 System at 1773 K

The utilization of rare earthRare earth resources, especially secondary resources (e.g., RE-oxide system slag), has been limited by the lack of thermodynamic information. In order to supplement and refine the thermodynamicExperimental thermodynamics data related to rare earthRare earth, the equilibrium experiments of SiO2-Ce2O3-CaO-25wt.% Al2O3 system phase diagram were carried out at 1773 K by the high-temperature isothermal equilibration/quenching technique in the current paper. The composition of seven phase regions was determined by FE-SEM, XRD, EPMA, and XRF analysis on the samples obtained by high-temperature equilibrium technology at 1773 K, including the primary crystal regions of three compounds (C2AS, 2CaO·SiO2, and CaO·2Ce2O3·3SiO2), three three-phase coexistence regions (L + C2AS + 2CaO·SiO2, L + C2AS + CaO·2Ce2O3·3SiO2, and L + CaO·2Ce2O3·3SiO2 + CeAl11O18), and a liquid region. The phase relations and isotherms of SiO2-Ce2O3-CaO-25wt.% Al2O3 system obtained in current work are beneficial to the recycling of rare earthRare earth resources containing cerium.