US2100927A - Continuous anode for electrolytic cells for the production of aluminum - Google Patents

Description

Nov. 30, 1937. R. TREMATORE CONTINUOUS ANODE FOR ELECTROLYTIC CELLS FOR THE PRODUCTION OF ALUMINIUM Filed July 17, 1934 lnvenlnr 000000000000 00 0000090 0 0vw0. 0n0w0w0m.

Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE CONTINUOUS ANODE FOR ELECTROLYTIC CELLS FOR THE PRODUCTION OF ALU- MINIUM Raflaele Trematore, Moi-i, Tr

to Det Norske Industri, Oslo,

ento, Italy, assignor Aktieselskab for Elektrokemisk Norway Application July 1'1, 1934, Serial No. 735,639 In Italy July 22, 1933 4 Claims.

consumed.

The present invention consists fundamentally in substituting for these connections threaded bars or tubes (hereinafter called bars) arranged inside the electrode, in such a way as to pass lengthwise through the self-baking mass without touching the external casing. The paste, as it bakes, assumes the shape of a female screw at the surface of contact with the current carriers, which can therefore be unscrewed progressively from the anode upwards as the need arises. The same tubes or bars may then also serve to suspend the anode itself. In order to allow the current carriers to be rotated easily without compromising their electrical contact, it is advisable to adopt a thread of special type, generated by the helicoidal movement of a scalene triangle, the longest side of which is parallel to the axis of the screw and the shortest side of which generates the helicoidal surface inclined downwards towards the axis of the screw (while the third side generates the helicoidal surface inclined upwards).

Figure 1 shows, in longitudinal section ll of Fig. 2), an illustrative example of the device claimed; Figure 2 shows, on the left, the same device as seen from above and. on the right, the same device in transverse section (22 of Fig. l)

3 shows the casing of the electrode. i represents the self-baking paste. 5 the current-carrying bars which, in the example given, are four in number.

The cell is provided with a cover 6 made of heat-insulating materials, composed of remov able sectors, on which a hopper l is arranged. This hopper surrounds the smooth surface of the electrode and serves to feed the alumina. In this Way, the latter is preheated at the expense of the heat which is developed during the baking of the electrodic paste. The material is discharged from the cell in such a way as to avoid corrosion of the electrode.

Devices for stirring the bath are arranged on the cover 6 and comprise horizontal arms 8 to which a vertical movement may be given by means of levers 9; the device shown in Figure 1 may be replaced by another device such as would cell, when the anode has to be lowered as it is.

allow also a horizontal movement around a vertical axis in order to depolarize the cell in case vertical stirring is not suflicient for the purpose. The operations of charging the alumina and ramming it may both be carried out separately in the various sectors of the cell.

Tube ID for the elimination of the gases and dust produced may also be arranged on the cover of the cell.

In the drawing, the cell is round and has one anode only. The devices described may, however, also be applied to other forms of cells and if desired, furnished with more than one anode.

The fundamental advantage of the invention is derived from the fact that the external casing of the anode is perfectly smooth and without holes or protuberances, in contrast to the types of cell used so far. This characteristic allows a more rational form to be given to the cell, facilitates the elimination of the gases freed (the cell may easily be covered) and offers the possibility of recovering the heat through the hopper 1. Moreover, the use of this device notably simplifies the suspension of the anode and diminishes the fall in tension inside the latter by reason of the minimum distance which can be maintained between the current carrier and the lower extremity of the electrodic paste. The operation of regulating the current carriers may be rendered continuous if a small motor is applied to effect their movement. The current carrying bars 5 are preferably set so that their lower ends are some distance back from the bottom of the electrode body 4 to protect them against melting and contaminating the bath.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. An anode for an electrolytic cell for the production of aluminum made from carbon paste that is baked during the operation in the cell, provided with current carrying threaded bars extending lengthwise through the electrode and being in contact with the baked as well as the unbaked part of said electrode, said bars being unscrewable upwards as and when it becomes necessary in order to avoid contact between them and the bath as the anode is consumed.

2. An anode for an electrolytic cell for the production of aluminum, made from carbon paste, that is baked during the operation in the cell, provided with at least four current carrying threaded bars extending lengthwise through the electrode and being in contact with the baked as well as the unbaked part of said electrode, said bars being unscrewable upwards as and when it becomes necessary in order to avoid contact between them and the bath, as the anode is consumeda 3. An anode for an electrolytic cell for the production of aluminum, made from carbon paste that is baked during the operation in the cell,

provided with current carrying threaded bars exand the shortest side oi. which generates the helicoidal surface inclined downwards towards the axis of the screw.

4. In combination with an electrolytic cell for the production of aluminum, an anode composed of carbon paste that is baked during the operation of. the cell, whereby the lower part of said anode-is normally baked and the upper part unbaked, and current carrying threaded bars extending longitudinally through the unbaked part of said electrode into the baked part thereof and terminating above the level of the electrolyte in the cell, said bars being mounted so that they can be turned to withdraw the same upward in said anode as the lower end of the latter is consumed.

RAFFAELE 'I'REMATORE.

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