Hydrodynamic and Thermoelectric 3D Mathematical Model of Aluminium Electrolysis Cell to Investigate Slotted Carbon Anode Efficiency

Abstract

Carbon anodes in Hall-Héroult electrolytic cell are the main source of carbon to reduce alumina into aluminium. Carbon dioxide resulting from the reduction reaction is evacuated through the lateral sides of the anode and through the slots. The shape and size of the slots is an important parameter for the anodes design. During manufacture, slots are formed in the anodes before or after baking. However, to avoid the stresses due to the introduction of slots in green anodes during molding, the solution is to saw the anodes after baking. The challenge here is to remove minimum carbon from the anodes while having high energy efficiency during electrolysis process. This study is conducted to test numerically different sawn slots configurations in the anode using a 3D mathematical model of the electrolytic cell. The model takes into account the main thermoelectric phenomena and flow dynamics that govern the operation of the electrolysis cell.