Ab initio molecular dynamics study on microstructure and diffusion properties of CaF2-2.2NaF-AlF3 system

Abstract The lack of micro-mechanism research on the influence of Ca2+ in cryolite molten salt has brought great difficulties to the improvement of current efficiency in actual production. The microstructure and diffusion characteristics of molten salt were studied by using ab initio molecular dynamics method, combined with the bridge fluorine distribution and diffusion coefficient of different complex ions. It is found that [AlF5]2−, [AlF6]3−, [AlF4]−, [Al2F9]3−and [Al2F10]4− coexist in molten salt system. With the increase of Ca2+, [AlF5]2− is more easily attracted by Ca2+ but has better self-diffusion performance, and [AlF6]3− is more easily crosslinked with other [AlFx](x−3)−.