US2526876A - Method of handling continuous electrodes - Google Patents

Method of handling continuous electrodes Download PDF

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Publication number
US2526876A
US2526876A US90594A US9059449A US2526876A US 2526876 A US2526876 A US 2526876A US 90594 A US90594 A US 90594A US 9059449 A US9059449 A US 9059449A US 2526876 A US2526876 A US 2526876A
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Prior art keywords
electrode
mass
casing
studs
temperature
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Expired - Lifetime
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US90594A
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English (en)
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Sejersted Johannes
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Elektrokemisk AS
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Elektrokemisk AS
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/16—Electric current supply devices, e.g. bus bars
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
    • C25C3/12—Anodes
    • C25C3/125—Anodes based on carbon

Definitions

  • This application relates to methods for handling continuous electrodes of the so-called Soderberg type and particularly to electrodes used for low voltage electrolytic work as in the case of aluminium furnaces.
  • Electrodes of this type are made by putting so-called paste into a casing having an internal shape corresponding to the shape of the desired electrode.
  • the paste is a mixture of carbonaceous material such as coke, and a binder.
  • the binder ordinarily has a melting point somewhat above normal atmospheric temperature so that the paste is solid at room temperature.
  • the upper part of the electrode (either at the top or a short distance down in the electrode mass) is hot enough so that the binder of the paste melts and ordinarily the paste flows without the necessity of tamping to take the shape of the electrode.
  • the nature of a type of paste commonly employed is described in U. S. Patent No. 1,670,052.
  • the present invention is dependent upon my discovery that the tendency of the electrode mass to bake onto the metal of the casing occurs after the mass has solidified and during the stage when the tars are finally carbonized.
  • a method of handling continuous electrodes in a furnace for producing aluminium or the like which comprises putting a paste mass into a casing having an internal section of the shape desired for the electrode. Such mass is then brought into a zone where it will melt to assume the shape of the electrode and is gradually moved downward into a zone hot enough to cause the mass, or at least its outer portion, to solidify but not to be fully carbonized.
  • the temperature at this stage is between 300 C. and about 400 C.
  • the electrode After emerging from this casing the electrode is lowered further into a, hotter zone where it is progressively heated until it becomes incandescent and carbonized fully. In this latter part of the operation, the sides of the electrode are not supported and this permits the decomposition products and vapors resulting from the cracking of the tars to escape outwardly through the sides of the electrode mass, and entirely prevents the mass from baking onto the casing.
  • the electrode finally enters the furnace bath in which it functions, which has a temperature of about 950 C.
  • the temperature at the bottom of the casing will be above about 300 C., a temperature necessary for solidifying but below the critical temperature of 425 C. which should not be exceeded.
  • the amount of lowering which is done at one time is only from 2 to 5 millimeters. In an aluminium furnace it is customary periodically for the aluminium to be tapped off and at this time a larger movement of the electrode is necessary.
  • the depth of aluminium tapped off is from 3 to 5 centimeters and would ordinarily not exceed 7 centimeters so that it is safe to assume that there is no necessity of lowering the electrode more than about 7.5 centimeters. Within this amount of movement there is virtually no danger of a non-solidified portion of the electrode mass coming down below the bottom of the electrode easin into an area where it will be unsupported on its sides.
  • This system contemplates the use of vertical studs.
  • One of the difficulties found with the use of vertical studs has been the tendency of the electrodes to crack.
  • the cracks ordinarily pass through the spaces in which the vertical studs are located. If such cracks run longitudinally of the electrode (which ordinarily is made with a length much greater than its width) there is a tendency for the gases generated at the bottom surface of the electrode to be caught by such cracks.
  • These gases consist largely of CO2, and there is a tendency for the CO2 to react with the carbon of the electrode to form CO, thus tending to increase the size of the cracks.
  • Such cracks also mean a higher voltage drop in the electrode and should therefore be avoided.
  • FIG. 1 shows a transverse section of an electric aluminium furnace embodying my invention
  • Fig. 2 shows a transverse section of one-half of a similar furnace illustrating a modified form of construction
  • Fig. 3 is a plan view of the electrode showing the location of the electrode studs.
  • the numeral I designates an electric aluminium furnace; 2 is the molten bath and 3 is the electrode provided with internal vertical contact studs 4 which extend down into the lower part of the electrode 3 where they are anchored in the carbonized mass.
  • the numeral 5 indicates that portion of the electrode 3 which is unbaked and pasty, and 6 is the portion of the electrode where a sullicient amount of volatile matter has been driven out of the paste so that the mass in this zone will be solid but not fully baked.
  • the approximate line of demarcation between portion 5 and portion 6 of the electrode mass is indicated by a dot and dash line.
  • I is the lower part of the electrode which is fully coked or carbonized and the approximate line of separation between the zone 1 and zone 5 is indicated by a dotted line. It is understood that these zones are not sharp and definite but are only approximated by the lines indicated.
  • the numeral I 5 indicates the casing for the electrode which is suspended from the usual superstructure (not shown) in any conventional manner.
  • the interior of this casing will ordinarily be rectangular with its length substantially greater than its width as indicated in Fig. 3. Since the electrode mass will slide smoothly within the casing I5 without any danger of sticking, it has been found that the height of this casing need not be as great as in previous constructions of this type.
  • the numeral 9 indicates a member which serves to form a gas-collecting duct or space around the lower portion of the electrode mass. This is preferably connected to the casing by a gas-tight sand lock I and at its lower end it is imbedded as at H in alumina which acts as a gas lock. Gases which occur within the space defined by member 9 may be led away through pipe II.
  • Fig. 2 the space around the lower part of the electrode is formed by a member I6 connected to the casing l5 by the sand lock l0 and to the furnace pot by the sand lock [3. Openings are formed in the top of member I6 and these are provided with removable covers H which connect with the member It by appropriate sand locks. These covers can readily be removed when additional alumina must be added to the furnace or when the crust has to be broken down, or other work done.
  • zone 1 is baked so hard that one cannot drive a metal bar into it without cracking it.
  • zone 6 while suiliciently solid so that it does not fiow, is soft enough so that a metal bar can be driven into it.
  • Fig. 3 I indicate the spacing of the electrode studs 4 relative to the casing I5. It will be noted as stated above, that thedistance between the center point of the studs longitudinally and taken in a horizontal plane is at least 33% greater than the distance from the center line of the outer row of studs to the outer margin of the electrode mass. By this arrangement if any shrinkage cracks occur, they will tend to run transversely out to the sides of the casing iather than longitudinally.
  • a method of handling a continuous electrode in an aluminium furnace which comprises shaping the electrode and baking it at a temperature of between 300 C. and 400 C. in a fixed casing whereby the outer portion of the electrode is solidified but not fully carbonized, withdrawing it downwardly from the casing at a temperature not in excess of 425 C., passing the electrode with its sides substantially unsupported downwardly towards and into the furnace bath while raising the temperature progressively to incandescent temperature whereby the electrode is fully carbonized, and maintaining a substantially gas-tight seal between the fixed casing and the lower surface of the bath surrounding the lower part; of the electrode whereby admission of air into the area surrounding the exposed portion of the electrode is substantially prevented and generated gases enter such area, and withdrawing portions of such gas from such area through an escape pipe so that a substantially non-oxidizing atmosphere around the electrode while passing it down from the fixed casing to the furnace bath.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Furnace Details (AREA)
  • Powder Metallurgy (AREA)
  • Inert Electrodes (AREA)
  • Fuel Cell (AREA)
US90594A 1948-05-08 1949-04-30 Method of handling continuous electrodes Expired - Lifetime US2526876A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO273464X 1948-05-08
NO669507X 1949-05-06

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US2526876A true US2526876A (en) 1950-10-24

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US (1) US2526876A (en(2012))
BE (1) BE488915A (en(2012))
CH (2) CH273464A (en(2012))
DE (2) DE814664C (en(2012))
FR (2) FR1055757A (en(2012))
GB (2) GB659509A (en(2012))

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2758964A (en) * 1952-08-12 1956-08-14 Aluminum Co Of America Continuous electrode and method of making the same
US2879213A (en) * 1956-10-22 1959-03-24 Frank A Howard Electrolytic method and apparatus
US2949430A (en) * 1956-08-07 1960-08-16 Ardal Og Sunndal Verk Process for the protection of carbon electrodes for electric furnaces
US3043755A (en) * 1959-05-25 1962-07-10 Aluminium Ind Ag Method for starting aluminum electrolytic cells with selfbaking anode and current supplying studs
US3254143A (en) * 1963-07-29 1966-05-31 Pennsalt Chemicals Corp Method for molding carbonized bodies
US3355604A (en) * 1962-05-18 1967-11-28 Comp Generale Electricite Continuous electrodes for magnetohydrodynamic generators
US3368960A (en) * 1961-02-21 1968-02-13 Elektrokemisk As Alumina reduction cell
US3495940A (en) * 1967-09-28 1970-02-17 Celanese Corp Production of high temperature resistant continuous filaments
US3673074A (en) * 1968-04-10 1972-06-27 Vaw Ver Aluminium Werke Ag Apparatus for improving the heat economy of an electrolytic cell for the production of aluminum
US5283026A (en) * 1989-12-12 1994-02-01 Kabushiki Kaisha Kobe Seiko Sho Method for molding fiber-reinforced composite material

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE977709C (de) * 1955-05-24 1968-08-08 Demag Elektrometallurgie Gmbh Feststehende Dauerform fuer selbstbackende Elektroden

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL52456C (en(2012)) * 1939-07-13
US1441037A (en) * 1923-01-02 soderberg
US1657948A (en) * 1924-01-17 1928-01-31 Norske Elektrokemisk Ind As Process in the employment of self-baking electrodes
US2193434A (en) * 1937-04-08 1940-03-12 Norske Elektrokemisk Ind As Electrode with slide contacts
US2224739A (en) * 1938-06-30 1940-12-10 Detnorske Aktieselskab For Ele Continuous electrode and method of supplying current thereto
US2243096A (en) * 1939-06-29 1941-05-27 Stanford A Hardin Electrode seal
CH227451A (de) * 1941-06-13 1943-06-15 Norske Elektrokemisk Ind As Selbstbackende Elektrode.
US2330576A (en) * 1941-04-02 1943-09-28 Hagerup-Larssen Georg Aluminum furnace
US2338936A (en) * 1941-05-23 1944-01-11 Hagerup-Larssen Georg Electrode frame structure
GB608475A (en) * 1941-06-13 1948-09-15 Norske Elektrokemisk Ind As Improvements relating to self-baking electrodes for electric furnaces
US2495148A (en) * 1943-05-08 1950-01-17 Tanberg Ragnar Method of manufacturing continuous electrodes

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1441037A (en) * 1923-01-02 soderberg
US1657948A (en) * 1924-01-17 1928-01-31 Norske Elektrokemisk Ind As Process in the employment of self-baking electrodes
US2193434A (en) * 1937-04-08 1940-03-12 Norske Elektrokemisk Ind As Electrode with slide contacts
US2224739A (en) * 1938-06-30 1940-12-10 Detnorske Aktieselskab For Ele Continuous electrode and method of supplying current thereto
US2243096A (en) * 1939-06-29 1941-05-27 Stanford A Hardin Electrode seal
NL52456C (en(2012)) * 1939-07-13
US2330576A (en) * 1941-04-02 1943-09-28 Hagerup-Larssen Georg Aluminum furnace
US2338936A (en) * 1941-05-23 1944-01-11 Hagerup-Larssen Georg Electrode frame structure
CH227451A (de) * 1941-06-13 1943-06-15 Norske Elektrokemisk Ind As Selbstbackende Elektrode.
GB608475A (en) * 1941-06-13 1948-09-15 Norske Elektrokemisk Ind As Improvements relating to self-baking electrodes for electric furnaces
US2495148A (en) * 1943-05-08 1950-01-17 Tanberg Ragnar Method of manufacturing continuous electrodes

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2758964A (en) * 1952-08-12 1956-08-14 Aluminum Co Of America Continuous electrode and method of making the same
US2949430A (en) * 1956-08-07 1960-08-16 Ardal Og Sunndal Verk Process for the protection of carbon electrodes for electric furnaces
US2879213A (en) * 1956-10-22 1959-03-24 Frank A Howard Electrolytic method and apparatus
US3043755A (en) * 1959-05-25 1962-07-10 Aluminium Ind Ag Method for starting aluminum electrolytic cells with selfbaking anode and current supplying studs
US3368960A (en) * 1961-02-21 1968-02-13 Elektrokemisk As Alumina reduction cell
US3355604A (en) * 1962-05-18 1967-11-28 Comp Generale Electricite Continuous electrodes for magnetohydrodynamic generators
US3254143A (en) * 1963-07-29 1966-05-31 Pennsalt Chemicals Corp Method for molding carbonized bodies
US3495940A (en) * 1967-09-28 1970-02-17 Celanese Corp Production of high temperature resistant continuous filaments
US3673074A (en) * 1968-04-10 1972-06-27 Vaw Ver Aluminium Werke Ag Apparatus for improving the heat economy of an electrolytic cell for the production of aluminum
US5283026A (en) * 1989-12-12 1994-02-01 Kabushiki Kaisha Kobe Seiko Sho Method for molding fiber-reinforced composite material

Also Published As

Publication number Publication date
FR60831E (fr) 1955-01-31
DE817959C (de) 1951-10-22
GB659509A (en) 1951-10-24
CH282267A (de) 1952-04-15
CH273464A (de) 1951-02-15
DE814664C (de) 1951-09-24
GB669507A (en) 1952-04-02
FR1055757A (fr) 1954-02-22
BE488915A (en(2012))

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