On the determination of ion transport numbers in molten salts using molecular dynamics

Study of the Partial Charge Transport Properties in the Molten Alumina via Molecular Dynamics

“…Nonetheless, here we clearly claim that in such situations, EMD data should be considered as a reference, as the method has already proven its high predictive capability for several dynamic and transport properties for both simple and complex molten ionically bonded systems. 18−22,25 Our calculated ionic conductivities are in good agreement with those of the two models. Both agree well with some data sets for both liquid and undercooled Al 2 O 3 : specifically, those reported by Shpil’rain et al 1 from melting temperature up to 3000 K, and those reported by Elyutin et al 4 below the melting temperature as low as 2050 K. Experimental data reported by Aleksandrov et al 2 and Arkel 6 are much higher than the other data sets and EMD calculations as well.…”

“…26,27 The procedure employed to perform the EMD simulations is the same as that in our prior work. 25 Two sets of interionic potentials are used in this work. The first one (EMD-1 in the following) is taken from Machado et al 28…”

“…Most of the time, in the literature, instead of the partial conductivity, the external transport number t i = σ i /σ is used to quantify the relative contribution of each ion to the total conductivity. The partial conductivity of i can be formulated as 25 where and ω i – j j quantify the interferences from other species on ion i , i.e., the mutual effect upon the total conductivity generated by various i – j pairs. Note that the ω i – j parameters are subjected to the constraint: ω i – j i + ω i – j j = 2.…”

“…If there is no solvent, it is rather natural to confer an equivalent role to the anions, since it is the cationic composition that mostly varies. When ions are strongly correlated and form coordination complexes, both cation and anions have similar interference contributions upon the partial conductivity and thus 25 It is important to note that the specific case of ω i – j j = 0 is not equivalent to Nernst–Einstein approximation because it accounts for correlations that may occur between same type of ions. Indeed, Nernst–Einstein (N–E) approximation assumes that the motion of ions within an electrolyte are uncorrelated.…”

On the Application of the FactSage Thermochemical Software and Databases in Materials Science and Pyrometallurgy

“…In Figure 17, we assume that the majority of the charge transfer is made by sodium cations and fluorine anions. In the literature, it is reported that about 90% of the charge is transferred by Na + ions and about 10% by F − ions [49][50][51][52][53]. The thermodynamic calculations are performed on a basis of 100 g of electrolyte.…”