US3775281A - Plant for production of aluminum by electrolysis - Google Patents

Plant for production of aluminum by electrolysis Download PDF

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Publication number
US3775281A
US3775281A US00174890A US3775281DA US3775281A US 3775281 A US3775281 A US 3775281A US 00174890 A US00174890 A US 00174890A US 3775281D A US3775281D A US 3775281DA US 3775281 A US3775281 A US 3775281A
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United States
Prior art keywords
cell
cathode
current
bars
anode beam
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Expired - Lifetime
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US00174890A
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English (en)
Inventor
Hatting W Schmidt
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Alcan Holdings Switzerland AG
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Alusuisse Holdings AG
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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

Definitions

  • PLANT FOR PRODUCTION OF ALUMINUM BY ELECTROLYSIS .oxide (A1 alumina) is dissolved in a fluoride melt.
  • Electrolysis is carried out in a temperature range of about 940 to 975C.
  • the cathodically deposited aluminium collects under the fluoride melt on the bottom of the cell.
  • Anodes of amorphous carbon are clipped from above into the melt.
  • the electrolytic decomposition of the alumina causes oxygen to form on the anodes and this combines with the carbon of the anodes to form CO and CO
  • FIGS. 1 and 2 of the accompanying drawings which are a longitudinal section and a transverse section.
  • a fluoride melt (the electrolyte) is contained in a steel pot 12 in which is a layer of insulation 13 and a carbon lining 11.
  • the insulation 13 is of refractory thermally insulating material.
  • Cathodically precipitated aluminium 14 collects on the bottom 15 of the cell.
  • the surface 16 of the liquid aluminium acts as the cathode.
  • lron cathode bars 17 are embedded in the bottom of the carbon lining 11 and serve to conduct current from the bottom of the cell to the exterior.
  • Anodes 18 of amorphous carbon dip into the fluoride melt from above so as to conduct the direct current to the electrolyte. They are fixed by rods 19 and clamps 20 to two anode bars 21. These together constitute an anode beam.
  • the electrolyte 10 is covered with a crust 22 of solidified melt and on top of this is a layer 23 of alumina.
  • the distance d from the underside 24 of the anode to the upper surface 16 of the aluminium (also called interpolar distance) canbe varied by raising or lowering of the anode beam 21,21 with the aid of the lifting mechanisms 25 which are mounted on columns 26.
  • the anodes are consumed on their underside to an extent of about 1.5 to 2 cm each day according to the particular construction of the cell.
  • the cathode bars 1'7 have two tasks. They collect the current from the active part of the carbon bottom beneath the anodes 18 and they conduct it out of the cell.
  • cathode bars serve as pure current conductors. From each cell cathode bus bars 30 conduct the current from terminals at the outer ends of the cathode bars 17 to the anode beam 21, 21 of the following cell.
  • the horizontal current density components in cooperation with the magnetic induction can cause a force field distribution in the liquid metal which is not free from rotation.
  • the consequence of this is a flow of metal combined with a major doming up of metal which in turn is caused by current density components induced by this movement of a current conductor in a magnet field. Doming up and movement of metal are detrimental to the electrolytic efficiency (ratio of the quantity of aluminium actually obtained to the quantity theoretically precipitated according to Faraday). If the electrolytic efiiciency falls the electric energy consumption rises (kWh/kgAl). If therefore only vertical current density components are present in the metal and in the melt, a doming up of metal without metal movement is impossible. Nevertheless, there may be a rotation drive in the metal, as shown by the following equation of the volume forces k:
  • j,, j and j signify the current density components in the metal in the three axial directions and 8,, B and B the corresponding components of the magnetic induction. If it is ensured that the current withdrawal through the carbon bottom at the underside of the liquid metal corresponds to the current feed at the upper side of the metal, the following components are zero:
  • the present invention is concerned with achieving this uniformity of current.
  • a plant for the production of aluminium by electroysis of alumina in a melt comprises a plurality of cells in series, each cell comprising a pot having a carbon bottom in which are embedded a plurality of like parallel horizontal cathode bars which each extend to at least one terminal outside the pot, and an anode beam (the last one to give its current to the cathode bus bar and the last one before the current enters the anode beam of the followng cell points A, B, C, etc., in FIG.
  • each connecting means comprising a plurality of cathode bus bars each of which connects a respective group of at least one of the cathode bar terminals of one cell to the anode beam of the next cell, the cross sections of the individual bus bars being such that, when an equal current flows through each cathode bar, then the voltage drop is the same along each bus bar from the respective bar terminal nearest to the anode beam to a point midway along the anode beam.
  • FIG. 4 shows an equivalent resistance substitute circuit diagram calculated from the liquid aluminium of one cell to the middle M of the anode beam of the following cell.
  • R B is the proportional bottom resistance for an iron cathode bar, calculated from the liquid aluminium to the outer end of the cathode bar.
  • a first cathode bus bar collects the current from n cathode bar terminals and has an electric resistance R from the last cathode bar terminal (point A) to the commencement of the anode beam of the following cell.
  • the second cathode bus bar with its own resistance R from its last cathode bar terminal (point B) to the commencement of the anode beam of the following cell collects the current from n terminals, a third bus bar, with its own resistance R the current from n terminals and so on.
  • R is the resistance of the anode beam of the following cell calculated to the middle M of the anode beam.
  • I is the total cell current.
  • Each cathode bar should conduct the same current I,,. No horizontal current density components occur in the longitudinal direction of the cell in the liquid aluminium if the cross sections of the individual bus bars are so chosen that the voltage drop in each cathode bus bar, from the point of feed of the last iron cathode bar terminal (points A,B,C etc) to the middle M of the anode beam of the following cell is the same.
  • a current n I flows, in the second bus bar nzlg, in the third bus bar a current r1 1 and so on.
  • the calculation must take place as if the current I from the anode beam of the following cell were not tapped continuously but at a point exactly in the middle of the cell (point M).
  • FIG. 3 of the accompanying drawings is a diagrammatic plan of an actual layout. It shows a series of three cells A,B,and C.
  • each cell includes three groups D,E,F of iron cathode'bars on each side.
  • Each group comprises three iron cathode bars G, H, J and a respective bus bar K.
  • two bus bars K are connected to the left end of the anode beam and one bus bar K to the right end.
  • L denotes the direction of the pot line current.
  • a complete series comprises from a few cells up to or more. At the first cell of the series the invention is only to be applied to the bus bar connection to the second cell. At the end of the series, all bus bars are connected together.
  • the number of the iron cathode bars depends on the size of the cell, on the current intensity and on several other factors; for example, a 100,000 Ampere cell can include between 10 and 20 cathode bars (meaning between 10 and 20 protruding ends on each side; often the cathode bars are divided in the middle of the carbon bottom, that is to say that two halves are disposed in such a way that they have a common axis but do not touch each other).
  • the number of bus bars there are many possibilities from one bus bar for each cathode bar to only one bus bar for all cathode bars together on each side.
  • the cells are end to end. They may alternatively be side by side.
  • the anode beam can consist of one or more single anodic bus bars.
  • the anode beam 2L consists of two anodic bus bars.
  • a plant for the production of aluminum by electrolysis of alumina in a melt comprising a plurality of cells in series, each cell comprising a pot having a carbon bottom in which are embedded a plurality of like parallel horizontal cathode bars each having at least one terminal extending outside the pot, and an anode beam carrying anodes arranged to dip into melt in the pot, and electrical connecting means between each cell and the next in the series, each connecting means comprising a plurality of bus bars each of which connects a respective group of at least one of said cathode bar terminals of one cell to the anode beam of the next cell, the cross sections of the individual bus bars being such that, when the equal current flows through each of said cathode bars; then the voltage drop is the same along each bus bar from the respective bar terminal nearest to the anode beam to a point midway along the anode beam.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
US00174890A 1970-09-01 1971-08-25 Plant for production of aluminum by electrolysis Expired - Lifetime US3775281A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1310070A CH542933A (de) 1970-09-01 1970-09-01 Aus einer Reihe von Zellen für die Gewinnung von Aluminium durch Elektrolyse bestehende Anlage

Publications (1)

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US3775281A true US3775281A (en) 1973-11-27

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ID=4389297

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US00174890A Expired - Lifetime US3775281A (en) 1970-09-01 1971-08-25 Plant for production of aluminum by electrolysis

Country Status (14)

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US (1) US3775281A (is)
JP (1) JPS5242727B1 (is)
AT (1) AT317565B (is)
AU (1) AU461746B2 (is)
BE (1) BE771940A (is)
CA (1) CA943907A (is)
CH (1) CH542933A (is)
DE (1) DE2143602C3 (is)
FR (1) FR2105172B1 (is)
GB (1) GB1352269A (is)
IS (1) IS880B6 (is)
NL (1) NL170162C (is)
NO (1) NO128774B (is)
ZA (1) ZA715859B (is)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969213A (en) * 1973-10-26 1976-07-13 Nippon Light Metal Company Limited Aluminum electrolytic cells
US4049528A (en) * 1975-09-18 1977-09-20 Aluminum Pechiney Method and a device for the supply of electric current to transverse igneous electrolysis tanks to minimize effects of magnetic fields
DE2801650A1 (de) * 1977-01-19 1978-07-20 Pechiney Aluminium Schaltungsanordnung fuer die elektrische stromversorgung von elektrolysezellen in laengsanordnung
US4211626A (en) * 1978-06-07 1980-07-08 Kaluzhsky Nikolai A Dual current supply system for aluminum-producing electrolyzers
US4224127A (en) * 1978-08-04 1980-09-23 Swiss Aluminium Ltd. Electrolytic reduction cell with compensating components in its magnetic field
WO1997048838A1 (en) * 1996-06-18 1997-12-24 Comalco Aluminium Limited Cathode construction
FR3016895A1 (fr) * 2014-01-27 2015-07-31 Rio Tinto Alcan Int Ltd Dispositif de levage d'ensembles anodiques d'une cuve d'electrolyse.

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3009096A1 (de) * 1980-02-01 1981-08-06 Schweizerische Aluminium AG, 3965 Chippis Asymmetrische schienenanordnung fuer elektrolysezellen
CN1793432B (zh) * 2005-11-25 2010-06-02 贵阳铝镁设计研究院 铝电解槽阴极母线的配置方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575827A (en) * 1967-12-06 1971-04-20 Arthur F Johnson System for reduction of aluminum
US3607685A (en) * 1968-08-21 1971-09-21 Arthur F Johnson Aluminum reduction cell and system for energy conservation therein
US3616318A (en) * 1969-11-14 1971-10-26 Arthur F Johnson Aluminum reduction cell and process
US3617454A (en) * 1969-11-12 1971-11-02 Arthur F Johnson Bus structure from aluminum reduction cells

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL104954C (is) * 1954-02-09 1900-01-01

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575827A (en) * 1967-12-06 1971-04-20 Arthur F Johnson System for reduction of aluminum
US3607685A (en) * 1968-08-21 1971-09-21 Arthur F Johnson Aluminum reduction cell and system for energy conservation therein
US3617454A (en) * 1969-11-12 1971-11-02 Arthur F Johnson Bus structure from aluminum reduction cells
US3616318A (en) * 1969-11-14 1971-10-26 Arthur F Johnson Aluminum reduction cell and process

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969213A (en) * 1973-10-26 1976-07-13 Nippon Light Metal Company Limited Aluminum electrolytic cells
US4049528A (en) * 1975-09-18 1977-09-20 Aluminum Pechiney Method and a device for the supply of electric current to transverse igneous electrolysis tanks to minimize effects of magnetic fields
DE2801650A1 (de) * 1977-01-19 1978-07-20 Pechiney Aluminium Schaltungsanordnung fuer die elektrische stromversorgung von elektrolysezellen in laengsanordnung
US4211626A (en) * 1978-06-07 1980-07-08 Kaluzhsky Nikolai A Dual current supply system for aluminum-producing electrolyzers
US4224127A (en) * 1978-08-04 1980-09-23 Swiss Aluminium Ltd. Electrolytic reduction cell with compensating components in its magnetic field
WO1997048838A1 (en) * 1996-06-18 1997-12-24 Comalco Aluminium Limited Cathode construction
US6113756A (en) * 1996-06-18 2000-09-05 Comalco Aluminium Limited Cathode construction
FR3016895A1 (fr) * 2014-01-27 2015-07-31 Rio Tinto Alcan Int Ltd Dispositif de levage d'ensembles anodiques d'une cuve d'electrolyse.

Also Published As

Publication number Publication date
FR2105172A1 (is) 1972-04-28
GB1352269A (en) 1974-05-08
NL7111841A (is) 1972-03-03
NL170162B (nl) 1982-05-03
JPS5242727B1 (is) 1977-10-26
NO128774B (is) 1974-01-07
NL170162C (nl) 1982-10-01
BE771940A (fr) 1971-12-31
DE2143602B2 (de) 1975-03-06
DE2143602C3 (de) 1975-10-23
AU3290571A (en) 1973-03-08
IS880B6 (is) 1974-07-19
CA943907A (en) 1974-03-19
FR2105172B1 (is) 1975-02-07
CH542933A (de) 1973-10-15
ZA715859B (en) 1972-04-26
AT317565B (de) 1974-09-10
DE2143602A1 (de) 1972-03-09
AU461746B2 (en) 1975-06-05
IS2022A7 (is) 1972-03-02

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