Multicomponent diffusion in molten slags

A method for investigating the diffusion of metal cations in multicomponent slag systems was developed. This method used microprobe analysis and allowed the analysis of the diffusion of multiple species within a single system. This project focused on the diffusion behavior of manganese, iron, calcium, and silicon in silicate slags, in order to simulate industrial steel and ferromanganese production. The molecular structure of CaO-Al₂O₃-SiO₂ slags was investigated with Raman spectroscopy, and oxidation states of manganese and iron in slags of varying composition were determined. This study identified the variation in diffusivity of slag components with changes in composition and temperature of multicomponent slag systems. An empirical model based on the correlation between optical basicity and diffusivity was developed to predict the multicomponent diffusivity of ionic species in molten silicate slags. The model takes into account properties of the bulk slag and the network forming ability of the diffusing species. The relative rate of diffusion of metal cations is proportional to the optical basicity coefficient of that species, while the rate of diffusion of all species increases exponentially with the calculated optical basicity of the bulk slag.