Effect of Ce2O3 content on structure, viscosity, and melting properties of CaO-Al2O3-MgO-SiO2-Ce2O3 slag

To ensure the reliable operation of high aluminum steel smelting, it is common practice to employ low-reactivity CaO-Al 2 O 3 -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 Ce 2 O 3 content on the crystalline phase and structure within the CaO-Al 2 O 3 -MgO-SiO 2 slag. Concurrently, the slag properties of viscosity and melting temperature are assessed. The findings reveal that the principal crystalline phases in the CaO-Al 2 O 3 -MgO-SiO 2 slag include Ca 3 Al 4 MgO 10 , Ca 3 Al 2 O 6 , and MgO. Additionally, the introduction of Ce 2 O 3 leads to the formation of the high melting temperature CaCeAlO 4 phase, whose abundance correlates positively with the Ce 2 O 3 content. Ce 2 O 3 demonstrates efficient bridging oxygen bond disruption, causing the transformation of network former [AlO 4 ]-tetrahedron into network modifier [AlO 6 ]-octahedron. Simultaneously, Q 4 Al shifts to Q 2 Al and Q 3 Al in [AlO 4 ]-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 Ce 2 O 3 content is beyond 15 wt%, Q 2 Al and Q 3 Al transform into Q 4 Al , which lead to an upward trend in high-temperature viscosity. Furthermore, as the temperature decreases, the precipitation of the CaCeAlO 4 phase from the slag occurs. The content and precipitation temperature of CaCeAlO 4 increase with rising Ce 2 O 3 content, representing the primary factor behind the elevation of low-temperature viscosity and melting temperature.