A combined computational-experimental study on the effect of Na2O on the fluoride volatilization in molten slags

Volatilization of fluorides is a common phenomenon and an environmental concern in metallurgy, welding, glass, and other industries. In order to understand the effect of Na2O on the volatilization behavior of fluorides in molten slags, thermogravimetric analysis together with molecular dynamic (MD) simulation was employed in the present study. The MD simulation results are consistent with the thermogravimetric analysis (TGA). That is, the increase of Na2O promotes the volatilization of fluoride. Investigation of melt microstructure showed that the diffusion of Na+ plays a key role in the volatilization of fluoride. The main contributing microstructural factors to the diffusion coefficient of Na+ are the extent of polymerization in SiO and CaF networks and the NaF clustering. Collectively, this research offered a thorough understanding of the microstructure and process of fluorine volatilization in molten slags.