Methodology to optimize the anode performance

An aluminium smelter operating its pots with Soederberg technology has experienced a period with a very high number of anode problems, mainly occurring as spikes, hanging anode ends, leak in stud holes, vertical cracks and dusting. The anode problems hindered a planned amperage increase. This paper describes the methodology that was applied to identify the root causes of the problems and to solve them systematically. This methodology includes the following main steps: Initial plant audit; Revamping of equipment causing bottlenecks; Plant capability test; Dynamic process optimization DPO; Validation of improved anode quality and pot performance. By applying this methodology, the anode problems of the smelter could virtually be eliminated. As a consequence the key plant performance figures (current efficiency, carbon consumption, energy consumption and bubble noise) could be improved substantially. This allowed to increase the line current by 7 %.