Patent ID: 6682643
Filing Date: 2004-01-27
Classification: C25C

Abstract:
A cell for electrowinning aluminium from alumina dissolved in a fluoride-containing molten electrolyte, which cell has a length and a width, the length of the cell being greater than the width of the cell, and comprises a plurality of metal-based anodes provided with an oxygen evolving electrochemically active structure having a series of substantially vertical through-openings for escape of anodically produced gaseous oxygen, the electrochemically active structures facing and being spaced apart from an aluminium-wettable drained cathode surface on which aluminium is produced, the drained cathode surface being formed along the length of the cell by upper surfaces of a series of juxtaposed carbon cathode blocks, which cathode blocks have a length and a width, the length of the cathode blocks being greater than the width of the cathode blocks, and extend lengthwise across the width of the cell, the cathode blocks comprising a current supply bar extending along the length of the cathode blocks for connection to an external electric current supply, wherein the drained cathode surface is divided into quadrants by a longitudinal aluminium collection groove along the length of the cell and by at least one aluminium collection reservoir across the cell, the upper surface of the cathode blocks sloping down along the length of the cathode blocks towards the aluminium collection groove so that pairs of quadrants across the cell are inclined in a V-shape relationship, said aluminium collection groove being located along the bottom of the V-shape and arranged to collect molten aluminium draining from the drained cathode surface and evacuate the molten aluminium into the aluminium collection reservoir(s) during cell operation.