Aluminium Pechiney

Spyridon Casdas

Bernard Langon

Laurent Michard

The invention concerns a tank for the production of aluminum using the Hall-Heroult process by the electrolysis of alumina in a molten cryolite-base bath in an assembly formed by the grouping in series of a plurality of aligned tanks, each tank being formed by a rectangular metal casing whose major axis is perpendicular to the axis of the series and whose interior comprises a heat-insulating lining, a cathode formed by the juxtaposition in sealed relationship of carbonaceous blocks in which metal cathodic bars are sealed, the two ends of the cathodic bars, which issue from the carbonaceous blocks, forming the cathodic outputs which extend to the outside of the casing on the upstream and downstream sides thereof, in relation to the direction of flow of the current in the series, and to which there are connected the conductors for making an electrical connection with the following tank in the series; wherein in accordance with the invention, and in order to make the ohmic resistance of the two groups of upstream and downstream circuits, 11 and 13, substantially equal, in spite of their differences in length, the ohmic resistance of the ends of the downstream cathodic bars, 15, is higher than the ohmic resistance of the ends of the upstream cathodic bars 14. Equality of ohmic resistance as between the upstream and downstream circuits is achieved either by making the downstream cathodic outputs 15 of a material having a higher degree of resistivity than that of the material forming the upstream cathodic outputs 14, or by increasing the length and/or reducing the section of the downstream outputs 15.

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St Jean de Maurienne, France

Spyridon Casdas