Thermodynamic and Structural Properties for the FeO–SiO<SUB>2</SUB> System by using Molecular Dynamics Calculation

Abstract

Molecular dynamics (MD) simulation has been widely used as a very useful method for the calculation of thermodynamic, structural and transport properties for the molten slags and fluxes at high temperatures. In this study, MD simulation using the Born-Mayer-Huggins type pairwise potential with partial ionic charges has been used to calculate the thermodynamic, structural and transport properties for the FeO–SiO2 system. The calculated structural properties such as pair distribution functions and fractions of bonding types of oxygen (bridging, non-bridging and free oxygen) with silicon atoms in FeO–SiO2 melts were in good agreement with previously measured and estimated results, and also the self-diffusion coefficients of iron, silicon and oxygen have been calculated at various temperatures and compositions. The enthalpy, entropy and Gibbs energy of mixing for the FeO–SiO2 system were calculated based on the thermodynamic and structural parameters obtained from MD simulation. The phase diagram for the FeO–SiO2 system estimated by calculated Gibbs energy of mixing shows good agreement with observed result in the range from pure iron to fayalite, and the liquid–liquid immiscibility region in the FeO–SiO2 system has also been assessed by MD calculation.