Molecular dynamics simulations of microstructural properties of CaO–SiO 2 –TiO 2 fluorine-free slag systems

Abstract

The microstructural properties of F-free slag, the CaO–SiO₂–TiO₂ (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 TiO₂ 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 (Q³ and Q⁴), suggesting the simplification of melt polymerisation. Substituting CaO with SiO₂ and maintaining a constant TiO₂ level causes the microstructure of the slag to become more complex. Both SiO₂ and TiO₂ 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, TiO₂ is regarded as network former in terms of its structure within CST system when the content of TiO₂ excessed 28 mass%.