Effect of Coke Properties on the Bubble

The anodic reaction of aluminium electrolysis cells leads to the formation of CO2 bubbles, which partly screen the anode surface and leads to an increase in the cell voltage. An advantage of these bubbles is that the formation and release contribute to the stirring of the electrolyte; however, the screening of the surface increases the irreversible energy losses. In this study, the voltage and current oscillation due to bubble evolution during electrolysis with different anode materials were determined in a laboratory cell. The investigation focused on the effect of coke sulphur content and grain sizes. It was found that anodes with finer coke fractions exhibited lower oscillations compared to their coarser fraction equivalents. Moreover, the influence of current density on the amplitude of the anode potentials was measured, revealing that a 64% increase in current density caused an increase in anode potential oscillations from 79% to 170%. This research provides insights into how coke properties can affect bubble behavior and electrolysis efficiency, potentially informing future practices in the aluminum production industry.