A PRELIMINARY FINITE ELEMENT ELECTROCHEMICAL MODEL FOR MODELLING IONIC SPECIES TRANSPORT IN THE CATHODE BLOCK OF A HALL-HéROULT CELL

摘要

A first 2D transient isothermal model was developed for themodelling of bath penetration in a Hall-Héroult cell cathodeblock. The model simulates the ‘non convective’ ionic speciestransport. The molten cryolite solution system is defined with anionic model. The migration and diffusion of the ionic species isfollowed in the cathode block pores and in an overlying bathlayer. The evolution of the potential is simultaneously obtainedusing charge conservation equations. The model includes a linearkinetic model for the electrochemical formation of metallicaluminium. The porous cathode behaviour is modelled usingvolume averaging based methods. The aluminofluoride ionicequilibrium is implemented by the penalty method and theelectroneutrality criterion as a constraint on the FEM weak form.This is the first application of porous electrode theory, adapted fora molten salt, to Hall-Héroult cell cathodes. The results show theearly stage evolution of voltage and ion distributions.