Viscosity-structure-crystallization of the Ce2O3-bearing Calcium-aluminate-based Melts with Different Contents of B2O3

In order to restrain the slag-metal interface reaction in the process of heat resistant steel continuous casting, the aluminate-based mold flux was devised. The effect of B2O3 on the viscosity, structure and crystallization property of the aluminate-based melts was studied. Appropriately adding B2O3 could decrease the viscosity of the melts. However, the viscosity could remain relatively constant when the addition of B2O3 exceeded 5 mass%. The structures of the melts, which were correlated to the viscosity, were confirmed through Fourier transformed infrared spectroscopy. The main network former of the melts was AlO4-tetrahedral unit. With adding B2O3, B2O3 formed 2D BO3-triangular unit, the bridging oxygen of the network combined by AlO4-units was broken, the polymerization of the melts decreased, and the viscosity, the apparent activation energy decreased consequently. With no B2O3 addition, the main crystalline phase was CaO. Because of Ca–O have the strongest interaction force and the weakest irregular thermal motion. The crystallization of CaO could be restrained by adding B2O3, the crystalline phase transferred from CaO to LiAlO2 and CaCeAlO4. CaCeAlO4 precipitated later than LiAlO2 because of the different interactions and the irregular motion ability of different structure units.