Patent ID: 6797148
Filing Date: 2004-09-28
Classification: C25C

Abstract:
A drained-cathode cell for the electrowinning of aluminium from alumina dissolved in a fluoride-containing molten electrolyte, comprising one or more anodes and one or more cathodes, the or each anode and cathode respectively having a sloped V-shaped or inverted V-shaped active anode surface and parallel sloped V-shaped or inverted V-shaped drained cathode surface facing one another and spaced apart by two sloped inter-electrode gaps, the cell further comprising vertical and horizontal passages for guiding an electrolyte circulation from a top part to a bottom part of each inter-electrode gap, said passages being delimited by surfaces of the anodes and/or cathodes and comprising:a vertical passage that extends from a top to a lower part of a cathode and leads to a horizontal passage that extends in or under the lower part of the cathode, and/or a horizontal passage that extends in or on an upper part of an anode and leads to a vertical passage that from the upper to a bottom part of the anode, each horizontal passage extending stibstantially over the entire horizonta; length of a corresponding inter-electrode gap, the cell being so arranged that during use the electrolyte circulates upwardly in the sloped inter-electrode gaps assisted by anodically produced gas and then returns via said vertical and horizontal passages from the top part to the bottom part of each inter-electrode gap.