Effect of Using a Copper Insert on Stability and Energy Balance in an Aluminum Production Cell

Roughly half of the electrical energy input to a modern Hall-Heroult cell for the aluminum (Al) production is lost as heat. Naturally, significant efforts are currently directed toward increasing the thermal efficiency of the cell by a variety of means. In this work, a slice thermoelectric model of a Hall-Heroult cell was developed for a conventional base model (insert-free collector bar) as well as for a copper (Cu) insert model (cylindrical copper inserts in the steel collector bar). Finite element method-based simulations were carried out to determine the components of voltage drops, steady-state ledge profile, cell stability and the overall heat balance. Comparison of the specific energy consumption (SEC) and the cell current in all cases highlighted the advantages of copper insert collector bar assembly over the insert-free, base case. The use of a Cu insert can increase the plant productivity by over 5% at the same SEC as in the base case. Moreover, with the introduction of an insert, an increase in productivity with a concomitant decrease in the SEC could be achieved.