Current Efficiency Measurements in Laboratory Aluminium Cells—V. The Influence of Stirring and LiF Additions

Abstract The current efficiency (CE) was measured in a 5A laboratory cell by analyzing the anode gases. Stirring was achieved by bubbling an inert gas through the electrolyte or by using a mechanical stirrer. The CE decreased with increasing intensity of stirring provided the bulk of the electrolyte was set in motion. This indicates that the process governing the loss in CE is mass transfer controlled. Experiments were performed with cryolite-alumina mixtures containing up to 10wt% LiF. The additions of LiF had no significant effect on the CE when the temperature was kept constant. Resume On a mesure le rendement electrique d'une pile experimentale en aluminium, d'une capacite de 5 A, en analysant les gaz anodiques. L'electrolyte de la pile a ete agite soit en y barbottant un gaz inerte, soit per l'action d'un agitateur mecanique. En autant que le gros du liquide electrolytique etait agite, une augmentation de l'agitation avait pour effet une diminution du rendement electrique. On peut en deduire qu'un me...