Effect of Ce 2 O 3 content on structure,viscosity,and melting properties of CaO-Al 2 O 3 -MgO-SiO 2 -Ce 2 O 3 slag

To ensure the reliable operation of high aluminum steel smelting, it is common practice to employ low-reactivity CaO-Al₂O₃-based slag. Various analytical methods, including scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and so on, are employed to investigate the impact of Ce₂O₃ content on the crystalline phase and structure within the CaO-Al₂O₃-MgO-SiO₂ slag. Concurrently, the slag properties of viscosity and melting temperature are assessed. The findings reveal that the principal crystalline phases in the CaO-Al₂O₃-MgO-SiO₂ slag include Ca₃Al₄MgO₁₀, Ca₃Al₂O₆, and MgO. Additionally, the introduction of Ce₂O₃ leads to the formation of the high melting temperature CaCeAlO₄ phase, whose abundance correlates positively with the Ce₂O₃ content. Ce₂O₃ demonstrates efficient bridging oxygen bond disruption, causing the transformation of network former [AlO₄]-tetrahedron into network modifier [AlO₆]-octahedron. Simultaneously, Q⁴_Al shifts to Q²_Al and Q³_Al in [AlO₄]-tetrahedron, resulting in a marked reduction in degree of polymerization of slag. This reduction is evident in decreased viscosity and melting temperature, reaching the minimum value of 0.153 Pa·s and 1331 °C, respectively. However, the Ce₂O₃ content is beyond 15 wt%, Q²_Al and Q³_Al transform into Q⁴_Al, which lead to an upward trend in high-temperature viscosity. Furthermore, as the temperature decreases, the precipitation of the CaCeAlO₄ phase from the slag occurs. The content and precipitation temperature of CaCeAlO₄ increase with rising Ce₂O₃ content, representing the primary factor behind the elevation of low-temperature viscosity and melting temperature.