Observation of Anodic Bubble Behaviors Using Laboratory Scale Transparent Aluminium Electrolysis Cells

Abstract

Laboratory scale transparent aluminum electrolysis cells were used to study anodic bubble behavior, including bubble layer thickness, bubble shape and coverage at the anode bottom surface, and the resultant cell voltage drop in a very similar environment to real industrial cells. The observation was conducted using two transparent cells, one with side-view and the other with a bottom-view cell design. For the side-observation experiment, the evolution of bubble layer thickness and bubble rising process were studied. In the bottom-observation experiment, bubble behavior was investigated on both unslotted and slotted anodes. Cell voltage was simultaneously recorded for a quantitative investigation of its relevance to bubble coverage. It was found that the cell voltage drop is very consistent with bubble coverage, with a high voltage drop corresponding to a high bubble coverage. The coverage of anodic gas bubbles decreases with the increase of current density. These phenomena were observed on unslotted and slotted anodes. The comparison of unslotted anode and slotted anode indicated that the slot significantly reduces the cell voltage drop, voltage drop fluctuations and bubble coverage.