Net Carbon Consumption in Aluminum Electrolysis: Impact of Anode Properties and Reduction Cell-Operation Variables

Abstract: In the Hall–Héroult aluminum production process, the amount of carbon consumed per ton of aluminum produced is an important metric. Deviations from ideal conditions in the reduction cells contribute to the discrepancy between the theoretical carbon consumption and the actual Net Carbon Consumption (NCC). Previous work from the authors, focused on predicting the net carbon consumption for individual anodes using partial least squares, was based on data collected by an anode-tracking system. In this paper, the importance of each aluminum production step to the NCC is identified and a link to the green anode properties is established. The data collected were analyzed using the sequential multi-block partial least-squares algorithm. The data were split in different blocks, determined by the manufacturing process sequence. The modeling showed that the top three most important blocks were alumina feeding metrics, baked anode properties, and green anode properties. Local green anode homogeneity was defined as resistivity variability metrics, calculated from the green anode resistance measurements. This local green anode homogeneity was found to be greater for anodes with low NCC. Graphical Abstract: [Figure not available: see fulltext.]