Structural and transport properties of FeO-TiO2 system through molecular dynamics simulations

Abstract

The viscosity of titanium slag has a crucial effect on the separation efficiency from metallic iron, the foaming extent of slag, and the kinetics of smelting reactions. Properties of slag depend on its microstructures essentially. Molten FeO-TiO2 system was investigated through molecular dynamics simulations to characterize its structural and transport properties at 1973 K. With FeO content increasing from 5 to 50%, CNTi-O decreases from 6.02 to 5.87, CNO-Ti decreases from 2.95 to 1.89, and the structural strength of the FeO-TiO2 system is hence reduced. [TiO6] octahedron is only one stable structural unit and is distorted in molten FeO-TiO2 system. [TiO6] octahedrons are connected by two ways: edge-sharing Ti-Ti and corner-sharing Ti-Ti. The edge-sharing Ti-Ti has stronger combining capacity than the corner-sharing Ti-Ti. The structural strength and viscosity of FeO-TiO2 system will be reduced by the transformation from Ti-O-Ti to Fe-O-Ti, which is resulted from the addition of FeO. Furthermore, the self-diffusion coefficients of Fe2+, Ti4+, and O2– follow the order: Fe2+ > Ti4+ > O2−. With FeO content increasing from 5 to 50%, the viscosity of molten FeO-TiO2 system decreases from 0.1272 to 0.0232 Pa·s. The results will contribute to understand and predict the macroscopic properties of high-temperature titanium slag.