Aluminium Pechiney

Aluminum Pechiney

Pechiney

Bernard Langon

Joseph Chaffy

Michel Leroy

Maurice Keinborg

Christian Duval

Paul Morel

Jean-Pierre Dugois

Benoit Sulmont

Jean-Louis Gerphagnon

Laurent Michard

Alain Vanacker

Gerard Laboure

Paul Bonny

George Duprat

Spyridon Casdas

Pierre Homsi

Alain Noizet

Superstructure for a very high power electrolysis cell for the production of aluminum using the Hall-Heroult process. The cell being formed of a heat-insulated metal casing of elongated parallelepipedic shape. The said superstructure comprising at least one rigid beam disposed along the long length of the casing, resting on supports, and supporting in particular the anodic frame structure to which are connected on the one hand the current risers coming from the preceding cell in the series and on the other hand the anode rods, characterized in that each rigid beam rests only upon supports placed between its ends, termed intermediate gantries. In that each anodic frame structure associated with each rigid beam includes electrical and mechanical connection or connectors to the anode completely fixed to the anodic frame structure and ensuring the contact and the clamping of each anode rod against it following lateral engagement and positioning of each rod in the corresponding connector.

Superstructure for a very high power electrolysis cell for the

The invention concerns a superstructure for a tank for the production of aluminum using the Hall-Heroult process by the electrolysis of alumina in molten cryolite, the tank being formed by a rigid metal heat-insulated casing of elongate parallelepipedic shape, the two ends of which are referred to as heads, and a superstructure formed by at least one rigid beam disposed along the long length of the casing, supporting in particular the anodic bus and the anodes and resting at its two ends on supports disposed at the two head ends of the tank, said superstructure being characterized in that each rigid beam is supported on at least one intermediate gantry in the central part thereof. The gantry may comprise four legs so as to constitute an inherently stable structure or it may be formed by two half-elements each provided with two legs. Preferably, each rigid beam is divided into two equal portions, the central ends of which are supported on the gantry.

Electrolysis tank superstructure with intermediate gantry, for the

The invention relates to a circuit for electrical connection between two successive cells of a series or row, designed for the production of aluminium by electrolysis of alumina dissolved in molten cryolite by the Hall-Heroult process at an intensity of at least 150 kA and possibly attaining from 500 to 600 kA. The circuit for the electrical supply of the cells comprises, in addition to the circuit 8 for the supply of electrolysis current, a distinct circuit 17 for correcting and balancing the magnetic fields which is formed by conductors which are substantially parallel to the axis of the series and are traversed by a direct current in the same direction as the electrolysis current which creates, in the cells, a vertical correcting magnetic field directed downwards close to the left-hand heads of the cells and directed upwards close to the right-hand heads of the cells. The total current J2 traversing the magnetic correcting circuit is at most equal to the electrolysis current J1 and is preferably between 4 and 80% of J1.

Device for connection between very high intensity electrolysis cells for

The invention relates to a circuit for electrical connection between the cells of a row designed for the production of aluminium by electrolysis, by the Hall-Heroult process. It is applied to rows of cells arranged transversely to the axis of the row operating at a current higher than 250,000 amperes and possibly attaining from 300 to 600 kA. An anode frame 6 of the cell of rank n+1 in each line is supplied with current simultaneously by a plurality of upstream risers such as 11, 12, 13 which are substantially equidistant and symmetrical about the vertical plane containing the small axis 1 of the cell and by at least two downstream risers 15, 15S which are substantially symmetrical about this same vertical plane, these downstream risers 15, 15S being supplied by conductors connected to the downstream cathode outputs 4 of the cell of rank n, at least a proportion 24 of these connecting conductors passing beneath the cell of rank n+1 along a path substantially parallel to the large axis of this cell, the direction of the current in these portions 24 of conductors passing from the heads 17 towards the small axis 1.

Circuit for the electrical connection of rows of electrolysis cells for

A process for automatically going into the mode for increased suction extraction of the gases emitted by the tanks of series for the production of aluminium by igneous electrolysis using the Hall-Heroult process, each tank being closed around its periphery by a plurality of removable covers which are disposed in substantially sealed relationship with each other and between each thereof and their support means on the periphery of the tank, the gases being collected over each tank by at least one duct connected to a centralized suction extraction system. The temperature of the gases in the duct is continuously measured. Opening of at least one cover gives rise to an abrupt drop in temperature, which makes it possible to put the system into the increased suction extraction mode, which will be automatically stopped when, all the covers being closed again, the temperature of the gases will substantially resume its initial value. The power required for the suction system is thus substantially reduced.

Process and apparatus for automatic increased suction extraction on

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.

Hall-Heroult electrolysis tank with asymmetrical cathodic bars and heat

The invention relates to a carbonaceous anode intended for cells for the production of aluminium by igneous electrolysis according to the Hall-Heroult process, which is connected to the positive current input by at least one steel conductor comprising a lower portion which penetrates into the carbonaceous anode and an upper portion which is connected to the positive current input. The upper portion of the steel conductor has, over at least 30% of the length of the upper portion, a cross sectional area which is at most equal to 60% of the cross sectional area of the lower portion. The upper portion may be constituted by a solid profile of reduced cross section or a tubular profile. The invention can be applied to prebaked anodes and to Soderberg anodes. It allows a substantial gain over the voltage drop in the anodic system.

Carbonaceous anode with partially constricted round bars intended for

The invention relates to a carbonaceous cathodic block having a low voltage drop, which is intended for tanks for the production of aluminium by electrolysis using the Hall-Heroult process, said tanks comprising a parallelepipedic metal casing supporting a cathode on which the layer of liquid aluminium is formed, said cathode being formed by the juxtaposition of parallelepipedic carbonaceous blocks of elongate shape wherein the ratio of the length of the major axis to the width is at least equal to two and in which there is cut at least one groove into which is sealed a steel bar which is disposed in parallel relationship to the short side of the casing and which connects to at least one cathodic collector, characterized in that the sealing grooves are cut in the direction perpendicular to the major axis of the block which is itself disposed in parallel relationship to the long side of the casing.

Modular cathodic block and cathode having a low voltage drop for

The present invention concerns an electrolysis tank for the production of aluminum by means of the Hall-Heroult process, which operates at above 250,000 amperes, in particular from 270,000 to 320,000 amperes. The connection between each riser (7) and the anodic bus bar (5) is made by way of flexible electrical conductors (8); the central riser (7C) is disposed on the axis of the series, the two intermediate risers (7B, 7D) and the two equally spaced lateral risers (7A, 7E) through which substantially equal current strengths flow are connected to six upstream cathodic collectors (3), two central collectors (3A, 3B) two intermediate collectors (3C, 3D) and two lateral collectors (3E, 3F), and three downstream cathodic collectors (4), a central collector (4A) and two lateral collectors (4B, 4C). Equipotential connections provide for balancing of the current between the different sections of the upstream and downstream collectors. Those tanks are very stable in operation and have a high level of efficiency in regard to energy consumption.

Electrolysis tank with a current strength of greater than 250,000

A process and apparatus for controlling the rate of introduction and the content of alumina to a tank for the production of aluminium by the electrolysis of dissolved alumina in a cryolite-base bath, the upper part of which forms a solidified crust, and wherein the alumina content is maintained within a narrow range, of between 1% and 3.5%, wherein the alumina is introduced directly into the molten cryolite bath by way of at least one opening which is kept open in the solidified crust and the rate at which the alumina is introduced is modulated relative to variations in the internal resistance of the tank during predetermined periods of time, with alternation of the cycles of introducing alumina at a slower rate and at a faster rate than the rate corresponding to normal consumption within the tank.

Process and apparatus for accurately controlling the rate of

The invention relates to a method of improving the current supply of electrolysis cells such as used in the production of aluminum by igneous electrolysis of alumina dissolved in cryolite, in which the cells are aligned in a lengthwise direction, allowing the harmful influence of the induced magnetic fields to be reduced. In a series, each cell is supplied with current from the preceding cell both via the head and via at least one side riser. The output of the cathode bars are divided into two separate groups, the upstream group supplying the head of the subsequent cell and the downstream group supplying the side risers of the subsequent cell. This produces a substantial improvement in the efficiency and a greater regularity.

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Saint Jean de Maurienne, France

Bernard Langon