Reducing PFCs with Local Anode Effect Detection and Independently Controlled Feeders in Aluminum Reduction Cells

The global warming potential of perfluorocarbons (PFCs) is much higher than that of CO2 in the aluminum reduction industry; hence, the release of PFCs is becoming increasingly regulated. Mitigation of PFC release by reducing anode effects (AEs) occurring during aluminum reduction is challenging. In this study, online anode current measurements were conducted at the anode beam of 400-kA cells, following which a simple local AE detection model was developed for AE prediction. A satisfactory AE true positive prediction rate of 80.3% was obtained in an industrial test. An independently controlled feeder strategy was then developed and applied to cells integrated with the local AE detection and prevention. The results show that the process provides an improved current efficiency with low direct current power consumption. Finally, the immense potential to reduce AE is confirmed with twinkling AEs and normal AEs, and daily AE duration decreased by 42.8%, 60%, and 56.9%, respectively.