Magnetohydrodynamics in advanced Hall–Heroult cells: physical modelling of flow in a laboratory scale cell

Abstract

The need to reduce the anode to cathode gap (ACG)^† has led to the concept of advanced Hall–Heroult cells. Electrolyte flow will have a major influence on the dynamics of advanced Hall cells. However, studies on the fluid flow pattern in the ACG of advanced Hall cells are limited. Although both electromagnetic forces and the bubble buoyancy effects cause electrolyte flow, the effect of the former has not been sufficiently investigated. Hence electromagnetically driven flow in advanced Hall–Heroult cells has been simulated in a laboratory scale cell with Wood's metal as the electrolyte. A thin, solid aluminium layer mimics the cathode. Velocity measurements suggest that electromagnetically driven velocities, ∼40–50 mm s^-1, are of the same order as bubble buoyancy driven flow, as expected in industrial Hall cells. This investigation also sheds light on the effect of important process parameters such as the anode to cathode distance and current density on flow in advanced Hall cells.