Accurate Viscosity Prediction for Molten Slags: A New Model and Database

Abstract

We present a new structurally-based viscosity model and database for accurately predicting the viscosity of multicomponent molten slags in the whole composition and large temperature ranges. The model is based on the CALPHAD (CALculation of PHAse Diagrams) approach and the thermodynamic two-sublattice ionic liquid formalism, which means that the underlying structure of oxide melts is taken into account and a full description of a multicomponent system is achieved by using the information of only binary and ternary systems. The model is implemented in the Thermo-Calc software package and is applied to optimize model parameters for the FeO_x–CaO–MgO–Al₂O₃–SiO₂–CaF₂–CrO_x–Na₂O–MnO_x–TiO₂–ZrO₂–P₂O₅–Gd₂O₃–La₂O₃–V₂O₅–NiO–CuO_x system. Encompassing the obtained viscosity model parameters, the new thermodynamic database TCOX10 is shown to be able to give highly reliable calculation results for industrial and geological applications. Compared with previously reported modelling work by using the same large experimental datasets on the key subsystem CaO–MgO–Al₂O₃–SiO₂ (CMAS), the present model and database are found to give the smallest deviations to the measurements, which is also proved true for the CMAS-based multicomponent glass that can significantly impact the performance of airplane turbine engines.