Patent ID: 6692620
Filing Date: 2004-02-17
Classification: C25C

Abstract:
A drained-cathode cell for the electrowinning of aluminium from alumina dissolved in a fluoride-containing molten electrolyte, comprising:a cell bottom comprising an arrangement for collecting product aluminium and a peripheral upper surface that surrounds the arrangement for collecting product aluminium, at least the part of the cell bottom which is in contact with molten aluminium during operation being made of material resistant to molten aluminium; at least one drained cathode surface on which aluminium is produced and from which the produced aluminium drains into said arrangement for collecting the product aluminium during operation; one or more thermic insulating sidewalls extending generally vertically upwards from said peripheral surface to form with the cell bottom a trough for containing during operation molten electrolyte and the product aluminium; and a sidewall lining made of material resistant to molten electrolyte but liable to react with molten aluminium and which material lines the thermic insulating sidewall(s) above said peripheral surface, the thermic insulating sidewall(s) inhibiting formation of an electrolyte crust or ledge on the sidewall lining that during operation remains permanently exposed to molten electrolyte above and around said peripheral surface, said peripheral surface being arranged to keep molten aluminium away from the sidewall lining above and around the entire peripheral surface, whereby the molten aluminium is prevented from reacting with the sidewall lining above and around the entire peripheral surface.