Viscosity estimation models for ternary slags

Five models to estimate slag viscosity have been compared with the experimental data obtained using the rotating cylinder method. The comparison was made for four ternary silicate systems, viz. FeO‐MgO‐SiO2, CaO‐MnO‐SiO2, FeO‐MnO‐SiO2 and CaO‐FeO‐SiO2. The KTH model and the model using the Gibbs energy of mixing have been found successful in estimating the slag viscosity. On the other hand, the comparisons of the experimental results with the calculated viscosity using the Riboud, Urbain and NPL models have shown poor agreement. While the limited number of the data points used for parameter optimisation would be one of the reasons for the failure of the Riboud and NPL models when applied for these ternary systems, the description of the slag composition in Urbain's approach could probably explain the disagreement between the estimated and experimental viscosity. Further studies are needed for the KTH model to accommodate fluorides in the model structure.