Patent ID: 6783656
Filing Date: 2004-08-31
Classification: C25C

Abstract:
A cell for the electrowinning of aluminium from alumina dissolved in a fluoride-containing molten electrolyte, using anodes that are based on alloys of iron and at least one of nickel and cobalt for producing aluminium of low contamination and of commercial high grade quality, each anode having an oxygen evolving electrochemically active anode surface, the cell comprising a cathode having a drained cathode surface and operating at reduced temperature without formation of a crust or ledge of solidified electrolyte, wherein the molten electrolyte is substantially saturated with alumina, particularly on the electrochemically active anode surface, and contains dissolved species of at least one major metal that is present at the surface of the anodes and that is selected from iron, nickel and cobalt, said dissolved species being present in the molten electrolyte at or nearly at a saturation concentration so as to inhibit dissolution of the electrochemically active anode surface.