Aluminium electrowinning cells with inclined cathodes

Abstract

A cell for the electrowinning of aluminium () from alumina dissolved in a molten electrolyte comprises a generally horizontal cell bottom (), preferably aluminium-wettable, on which a pool of product aluminium () is collected from at least one electrically conductive cathodic element () having aluminium-wettable cathode surfaces (). The cathodic element comprises an inclined cathodic wall () in the electrolyte () above the generally horizontal cell bottom (). The cathodic wall () has an upwardly-oriented inclined face () that forms a sloping upper aluminium-wettable drained active cathode surface on which aluminium is produced and drains into the aluminium pool (), and a downwardly-oriented inclined face () which is in contact with the molten electrolyte () and which overlies the aluminium pool (). The aluminium pool () covers substantially the entire cell bottom () including underneath the cathodic wall (). A return path for alumina-enriched electrolyte () towards a bottom end of the anode-cathode gap () may be provided behind the cathodic wall () along an inactive surface () thereof. The cell may be fitted with anodes () that are foraminate, e.g. an arrangement of spaced apart parallel rods, or solid plates.