Patent ID: 6436273
Filing Date: 2002-08-20
Classification: C25C

Abstract:
An electrolytic cell for the electrowinning of aluminium from alumina dissolved in a fluoride-based molten electrolyte, comprising:a) a cathode cell bottom comprising sloped cathode faces in a generally v arrangement and a recessed groove or channel below adjacent bottom ends of the cathode faces and extending therealong, each sloped cathode face forming a drained cathode surface on which in use a layer of molten aluminium is produced and continuously drained into the recessed groove or channel; b) sloped anode faces in a generally v arrangement facing and parallel to the sloped cathode faces, each sloped anode face being so arranged that gas released thereon during electrolysis drives at least partly an electrolyte circulation between the facing sloped anode and cathode faces; and c) means for feeding alumina into the circulating electrolyte to enrich it with dissolved alumina; characterized in that a covering surface located at bottom ends of the sloped anode faces is spaced above and covers the recessed groove or channel such that under the effect of the electrolyte circulation produced by gas release the alumina enriched electrolyte is fed into the covered recessed groove or channel and circulated longitudinally therein along substantially the entire length thereof above the drained aluminium, said covered recessed groove or channel forming means for supplying the alumina-rich electrolyte circulating therealong to and along substantially the entire bottom ends of said sloped cathode faces under the effect of the electrolyte circulation produced by gas release.