Analysis of Microstructure Molecular Dynamics and Slag-Metal Reaction of Low-Basicity CaO-SiO2-Al2O3-MgO System Refining Slag

To clarify the effect of slag composition changes on the slag-metal interface reaction, the microstructure of the CaO-SiO2-Al2O3-MgO system molten refining slag is analyzed using molecular dynamics simulation. In the simulation results, it is shown that in the slag, the Si-O bond and Al-O bond mainly exist in a tetrahedral coordination, mainly including five structural forms: Q0, Q1, Q2, Q3, and Q4. In addition, Al-O also exists in a pentahedral and hexahedral coordination. With the increase of basicity, the proportion of aluminum-oxygen tetrahedral structure in the slag increases, the Al-O bond length decreases, and the average diffusion ability of each atom in the slag increases, which can promote the reduction of aluminum in the slag into the steel melt. With the increase of Al2O3 content, the degree of slag polymerization increases, the proportion of pentacoordinated and hexacoordinated aluminum increases, the Al-O bond length increases, and the average diffusion ability of each atom in the slag decreases, which can inhibit the reduction of aluminum in the slag into the steel melt.