Molecular dynamics simulations of microstructural properties of CaO-SiO2-TiO2 fluorine-free slag systems

The microstructural properties of F-free slag, the CaO-SiO 2 -TiO 2 (CST) systems, are investigated by molecular dynamics (MD) simulations. The results show that in the CST system, the average bond length of Si-O remains in 1.61 Å. The addition of TiO 2 contributes to the increase in the concentrations of 4-coordinated Si and 4-coordinated Ti. Increasing the amount of CaO decreases the proportion of bridging oxygen (BO) atoms and the degree of network connectivity (Q 3 and Q 4 ), suggesting the simplification of melt polymerisation. Substituting CaO with SiO 2 and maintaining a constant TiO 2 level causes the microstructure of the slag to become more complex. Both SiO 2 and TiO 2 contribute to the more complex structures of the melts. Simultaneously, Si-O-Ti linkages are more favourable than Si-O-Si or Ti-O-Ti linkages. Thus, TiO 2 is regarded as network former in terms of its structure within CST system when the content of TiO 2 excessed 28 mass%.