US3367855A

US3367855A - Invertible anode side channel

Info

Publication number: US3367855A
Application number: US408265A
Authority: US
Inventors: Francis H Fischer; Karl F Bartels; Delray E Fischer
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1964-11-02
Filing date: 1964-11-02
Publication date: 1968-02-06
Anticipated expiration: 1985-02-06

Description

Feb. 6, 1968 F. H. 'FISCHER ETAL 3,357,855

INVERTIBLE ANODE SIDE CHANNEL 2 Sheets-Sheet l Filed Nov. 2, 1964 IVENTORS DELAY FlsCER mmw ATTORNEY Feb. 6, 1968 F, H. FISCHER ETAL 3,367,855 i Filed Nov. 2, 1964 2 sheets-sheet a NNNNNNN R5 @ANOS H. FIS HER RL F. EART- DELRAY E. FlSCH BYJZMMMMMW ATTORNEYS United States Patent O 3,367,855 INVERTEBLE ANDE SIDE CHANNEL Francis H. Fischer and Karl F. Bartels, Portland, and

Delray E. Fischer, Corpus Christi, Tex., assignors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed Nov. 2, 1961i, Ser. No. 408,265 4 Claims (Cl. 204-67) This invention relates to an improved electrolytic cell for the production of metallic aluminum. More particularly, this invention is concerned with invertible anode side channels for such an electrolytic cell of the Sderberg or self-baking type.

Electrolytic cells for the production of metallic aluminum frequently employ self-baking, consumable, carbonaceous anodes encased and supported on at least two faces by courses of horizontal anode side channels which are in turn supported by the cell superstructure. To provide for its optimum insertion in the electrolytic bath, the anode is lowered as it consumed, the lowermost courses of side channels being removed when they approach sufficiently close to the hot electrolytic bath and additional channels being used to form a new top course as required. Electric current is supplied to the anode by steel anode pins extending into the anode through holes in the webs of the side channels. These anode pins, which are driven into the anode while it is in the unbaked or plastic condition, also transmit the weight of the anode to the side channels` The constant load on the side channels tends to distort and weaken them at the high temperatures present in the cell. In addition, the side channels beco'me eroded by the liquid bath or the atmosphere immediately above it. Since both of these phenomena become more pronounced toward the surface of the bath, their effects upon an individual channel are non-uniform. Accordingly, it has been found that inverting these side channels each time they are installed in a new top course, or at other convenient intervals, will prolong their useful life.

lt also has been found that increasing the depths of the side channels will result in a corresponding increase in their useful life and an inversely corresponding decrease in the frequency of removal of the lowermost courses of side channels. It also increases the strength and rigidity of the channels.

On the other hand, it is required that the anode pins be as close as possible to the surface of the bath in order to minimize the voltage drop in the portion of the anode therebetween. The limiting factor is the minimum allowable distance (approximately four inches in one particular cell, for example) between the lower flange of the lowen most course of side channels and the surface of the electrolytic bath. Allowing the two to come any closer results in unacceptable distortion or erosion of the channel by the bath.

The foregoing problems and requirements are met by providing, in accordance with the invention, a row of anode pin holes in the web of the side channel adjacent the top flange, and another row adjacent the bottom flange. It is presently preferred to insert the anode pins through only the lower row of holes.

For a better understanding of the invention, and of its other details, objects, and advantages, reference is now made to the accompanying drawings, which show, for purposes of illustration only, a present preferred embodiment of the invention. In the drawings:

FIGURE 1 is a general diagrammatic sectional View of an electrolytic cell showing one of the long sides of an anode and associated apparatus;

FIGURE 2 is a section taken along line II-ll of FIG- URE l; and

FIGURE 3 is a perspective view of a central portion of a side channel.

Referring now more particularly to the drawings, selfbaking anode 1 is formed by periodically placing a quantity of plastic, carbonaceous mixture in bottomless mold 2 supported on the superstructure (not shown) of the cell in the conventional manner. This anode l. is gradually baked into a hard condition as it passes downwardly toward hot bath 3 composed of alumina dissolved in cryolite. Layer 4 of molten aluminum lies on top of carbon cathode 5. Side channels n located adjacent opposite faces of anode 1 are prevented from moving laterally by bent angle irons 7 held in rigid position by supporting framework (not shown), a clearance of about 1Ainch being provided in order that the channels may slip past the angles freely as the channels are lowered with the consumption of the anode.

Each side channel 6 has an upper row tof holes 8A and a lower row of holes 8B extending through its web portion. Anode pins 9 are driven through lower holes 8B into anode 1 in its plastic or green state, the pins serving to support anode 1 when the side channel 6 through which they are inserted is on the bottom course. Channel bar 1li connects the adjacent ends of the side channels at the middle of the anode.

The center jack hanger strap 11 supports the channel bar 1b, which in turn supports side channels 6 at the middle of the anode when those channels are a part of the bottom course. This strap 11 is supported by suitable means (not shown) attached to the superstructure of the cell. This superstructure can be conventional in design and usually has jack screws which serve to raise and lower the center jack hanger strap as desired during the operation of the cell.

Suitable end channels (not shown) are connected to opposite end fittings (not shown) welded to the outer ends of side channels 6, and the resulting structure may be supported near the corners of the anode by other means (not shown) similar to jack hanger strap l1 and also attached to jack screws operating in synchronism with the center jack screws. Pins 24 connect channel clips 23 and adjacent channel flanges in order to give the structure greater strength.

Side channels 6 to the right of hanger strap 11 are interchangeable with those to the left of the strap and side channels d have greater depth (l5 inches rather than l0 inches, in one particular cell, for example), while at the same time anode pins 9 are brought closer to the surface of bath 3. This system extends the useful life of the side channels 6, decreases the frequency of removal of the lowermost channels, and minimizes the voltage drop in anode l between pins 9 and bath 3.

While present preferred embodiments of the invention and methods of practicing the same have been illustrated and described, it will be understood that the invention may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. In an electrolytic cell, an invertible anode side channel comprising: a web portion bounded by first and second flange portions, and first and second groups of spaced holes in said web portion for receiving anode pins, said rst and second groups of holes being adjacent said first and second flange portions, respectively.

2. In an electrolytic cell for the production of metallic aluminum having a self-baking, consumable, carbonaceous anode mounted for partial immersion in an electrolytic bath, a plurality of horizontal anode side channels disposed with their web portions abutting opposite faces of said anode, and electrically conductive anode pins connected to an external source of electric current and extending through said web portions and into said anode, the improvement comprising: upper and lower groups of spaced holes in each said web portion adjacent the upper and lower flanges respectively of each said channel, and at least the major portion of said pins extending through said lower groups of holes, thereby adapting said pins to be positioned relatively close to said bath to minimize the voltage drop in said anode between said pins and said bath while maximizing the distance between said bath and the closest said channels, yet enabling said channels to be used similarly in an inverted position.

3. An electrolytic cell for the production of metallic aluminum comprising in combination: a self-baking, consumable, carbonaceous anode mounted for partial immersion in an electrolytic bath; a plurality of horizontal anode side Channels disposed with their web portions abutting opposite faces of said anode; upper and lower groups of spaced holes in each said web portion adjacent the upper and lower anges respectively of each said channel; and electrically conductive anode pins connected to an external source of electric current and extending through holes in said lower group and into said anode; thereby adapting said pins to be positioned relatively close to said bath to minimize the voltage drop in said anode between said pins and said bath while maximizing the distance between said bath and the closest said channels, yet enabling said channels to be used similarly in an inverted position.

4. A method of producing metallic aluminum by operating an electrolytic cell having an electrolytic bath, a self-baking, consumable, carbonaceous anode partly immersed in said bath, a plurality of horizontal anode side channels disposed one above the other on opposite faces of said anode with their web portions abutting said faces, upper and lower groups of spaced holes in each said web portion adjacent the upper and lower flanges respectively of each said channel, and electrically conductive anode pins connected to an external source of electric current and extending through holes in said lower group and into said anode; said method comprising: lowering said anode toward said bath as said anode is consumed, repeatedly removing from a said face the lowermost of said channels when said lowermost channel is a predetermined distance from said bath, and thereafter re-installing at least some of the removed said channels in an inverted position as the uppermost of said channels on one said face, thereby maintaining said pins relatively close to said bath to minimize the voltage drop in said anode between said pins and said bath while maximizing the distance between said bath and the closest said channels.

References Cited UNITED STATES PATENTS 2,739,113 3/1956 Horseld et al. 204-243 HOWARD S. WILLIAMS, Primary Examiner.

D. R. VALENTINE, Assistant Examiner.

Claims

4. A METHOD OF PRODUCING METALLIC ALUMINUM BY OPERATING AN ELECTROLYTIC CELL HAVING AN ELECTROLYTIC BATH, A SELF-BAKING, CONSUMABLE, CARBONACEOUS ANODE PARTLY IMMERSED IN SAID BATH, A PLURALITY OF HORIZONTAL ANODE SIDE CHANNELS DISPOSED ONE ABOVE THE OTHER ON OPPOISTE FACES OF SAID ANODE OF THEIR WEB PORITONS ABUTTING SAID FACES, UPPER AND LOWER GROUPS OF SPACED HOLES IN EACH SAID WEB PORTION ADJACENT THE UPPER AND LOWER FLANGES RESPECTIVELY OF EACH SAID CHANNEL, AND ELECTRICALLY CONDUCTIVE ANODE PINS CONNECTED TO AN EXTERNAL SOURCE OF ELECTRIC CURRENT AND EXTENDING THROUGH HOLES IN SAID LOWER GROUP AND INTO SAID ANODE; SAID METHOD CONPRISING: LOWERING SAID ANODE TOWARD SAID BATH AS SAID ANODE IS CONSUMED, REPEATEDLY REMOVING FROM A SAID FACE THE LOWERMOST OF SAID CHANNELS WHEN SAID LOWERMOST CHANNEL IS A PREDETERMINED DISTANCE FROM SAID BATH, AND THEREAFTER RE-INSTALLING AT LEAST SOME OF THE REMOVED SAID CHANNELS IN AN INVERTED POSITION AS THE UPPERMOST OF SAID CHANNELS ON ONE SAID FACE, THEREBY MAINTAINING SAID PINS RELATIVELY CLOSE TO SAID BATH TO MINIMIZE THE VOLTAGE DROP IN SAID ANODE BETWEEN SAID PINS AND SAID BATH WHILE MAXIMIZING THE DISTANCE BETWEEN SAID BATH AND THE CLOSEST SAID CHANNELS.