Undissolved alumina in dynamic chunks piercing through the bath - metal interface in industrial aluminum electrolysis cells

In Hall–Héroult cells the uninvolved alumina precipitates on the top of the cathode to form resistive deposits which could significantly impact the energy consumption. A dynamic energy conservation (DEC) approach has been developed to quantify the flux of undissolved alumina piercing the interface between the electrolyte and the liquid metal in Hall–Héroult cells. The proposed DEC model considers both electrochemical and interfacial phenomenon between the electrolyte and the liquid metal. A critical radius at or below which a particle of undissolved alumina is retained at the electrolyte/liquid metal pad interface is defined and quantified considering the heat transfer and electrolysis cell operating parameters: temperature, electrolyte composition, alumina porosity, and current density. The proposed approach appears reliable to quantify the amount of undissolved alumina which pierces the electrolyte/liquid metal pad interface and precipitates to the bottom of the cell to form a deposit on the cathode.