Surface Tension Calculation of Molten Slag in SiO2–Al2O3–CaO–MgO–‘FeO’–‘Fe2O3’ Systems Based on a Statistical Modelling Approach

A calculation model for surface tension of molten slags in SiO2–Al2O3–CaO–MgO systems, based on a statistical modelling approach, was further extended to SiO2–Al2O3–CaO–MgO–‘FeO’–‘Fe2O3’ multi-component systems. A total number of 1493 surface tension data reported in literatures, including 661 iron-containing data in this study, have been collected and critically reviewed for optimizing model parameters. The model achieves an excellent agreement with literature values for iron -containing melts with an average error of 4.9% and overall absolute error of 29.75 mN/m. Moreover, the dependence of surface tension on composition and temperature the composition has been discussed using the present model. The results show that the surface tension always obviously decrease with the increment of SiO2 content and substitution of CaO or Al2O3 by MgO will cause a decrease in the surface tension. In case of silica-free ternary systems such as the Al2O3–CaO–‘Fe2O3’ and CaO–MgO–‘Fe2O3’, the surface tension decreases with increasing ‘Fe2O3’ concentration with constant Al2O3 and CaO level respectively, indicating the network former role of ‘Fe2O3’ in these studied systems. Temperature coefficient is closely related with the melt composition and positive values for high ‘FeO’ and ‘Fe2O3’ contents in the melts were found.