Estimating Viscosities in Iron and Steelmaking Slags in the CaO-Al2O3-MgO-SiO2-(TiO2) System with Basis on a Thermodynamic Model

Slags are critical components in several iron and steelmaking processes. In steelmaking, different slags with various properties are used in the different processing steps from melting and refining to continuous casting. Thermodynamic properties, viscosity and surface tension are among the most important properties considered in the design of slag compositions for steel processing. A brief literature review of the approaches at modeling viscosities shows that viscosity correlations with chemical composition, basicity (both chemical and optical), and more recently with slag constitution have been attempted with different degrees of success. In this work, a model based on the Riboud viscosity model combined with the thermodynamic Kappor-Frohberg-Gaye cell model is described and presented as a potential alternative to obtaining slag viscosity estimates directly from computational thermodynamics software. The first results of the adjustment and application of the model to the CaO-Al2O3-MgO-SiO2 system are presented. The quality of the adjustment is discussed as well as its current limitations. Future steps in the model development involve its extension to include FeO, TiO2, and CaF2.