On the analysis of ionic mass transfer i

An electrolyte typically used in an aluminum electrolysis cell comprises various ions moving in the electromagnetic field generated by the high intensity current required for industrial applications. The objective of this study is to model the transient behavior of these ions within a NaF‐AlF3‐Al2O3 mixture using a numerical finite element method. The electric potential field equation is solved, which governs electrochemical reaction kinetics at the electrodes, to derive the electric potential field, current density, and resultant heat generation in the cell. The concentration field for ionic species in the bath is also determined. Results indicate the formation of a high concentration gradient of electroactive ions such as Al2OF6 2/C0 and AlF4/C0 at the reacting electrodes over time, with diffusion identified as the primary mechanism for the transfer of these ions. Additionally, the investigation reveals that from the early stages of the 3-minute simulation of the electrochemical process, the difference between bulk and surface concentrations of electroactive ions remains constant. It is concluded that although diffusion dominates the flux of electroactive species, migration is the controlling mechanism for the transport of electroinactive ions.