EP1151150B1 - Graphit-kathode für die elektrolyse von aluminium - Google Patents

Graphit-kathode für die elektrolyse von aluminium Download PDF

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Publication number
EP1151150B1
EP1151150B1 EP00901691A EP00901691A EP1151150B1 EP 1151150 B1 EP1151150 B1 EP 1151150B1 EP 00901691 A EP00901691 A EP 00901691A EP 00901691 A EP00901691 A EP 00901691A EP 1151150 B1 EP1151150 B1 EP 1151150B1
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EP
European Patent Office
Prior art keywords
cathode
end regions
cathodes
central region
graphite
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP00901691A
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English (en)
French (fr)
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EP1151150A1 (de
Inventor
Jean-Michel Dreyfus
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Carbone Savoie SAS
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Carbone Savoie SAS
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Filing date
Publication date
Application filed by Carbone Savoie SAS filed Critical Carbone Savoie SAS
Publication of EP1151150A1 publication Critical patent/EP1151150A1/de
Application granted granted Critical
Publication of EP1151150B1 publication Critical patent/EP1151150B1/de
Anticipated expiration legal-status Critical
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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
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes

Definitions

  • the present invention relates to a graphite cathode for aluminum electrolysis.
  • an electrolytic cell In the electrolytic process used in most factories aluminum production, an electrolytic cell includes, in a box metallic sheathed with refractories, a cathode sole composed of several cathode blocks juxtaposed. This set constitutes the crucible which, rendered sealed by pot lining, is the seat of transformation, under the action of electric current, of the aluminum electrolytic bath. This reaction takes place at a temperature generally above 950 ° C.
  • the graphitization treatment of the graphite cathode increases the electrical and thermal conductivities, thus creating sufficient conditions for optimized operation of a electrolysis tank.
  • Energy consumption decreases due to decline the electrical resistance of the cathode.
  • Another way to take advantage of this decrease in electrical resistance consists in increasing the intensity of the current injected into the tank, allowing an increase in production aluminum.
  • the high value of thermal conductivity of the cathode allows the evacuation of the excess heat generated by the increase intensity.
  • graphite cathode vessels appear less electrically unstable, i.e. with less fluctuation in electrical potentials, than carbon cathode tanks.
  • the single figure of the attached schematic drawing shows a block cathode 3, with the cathode bars of current supply 2, the initial profile is designated by the reference 4.
  • the erosion profile 5, represented in dotted, shows that this erosion is accentuated at the ends of the block cathode.
  • Document FR 2 117 960 describes a cathode for the preparation aluminum by electrolysis.
  • This cathode is made from several semi-graphitic carbon blocks, with different resistivities each other.
  • This complex structure due to the juxtaposition of blocks with the electrical discontinuity which it involves, is justified not by a reduced erosion, since cathodes of this type are not sensitive erosion, but by a decrease in the swelling of the sole in the area Central.
  • the document FR 2 351 192 describes, in a device for production of aluminum, a cathode assembly comprising a bar cathodic and a carbon block separated by a heterogeneous interface allowing to vary over the length of the cathode assembly, the contact resistance between the cathode bar and the carbon block.
  • the erosion rate of a graphite cathode block is, by Consequently, its weak point, and its economic attractiveness in terms of gain of production may disappear if the service life cannot be increased.
  • the problem is therefore to reduce erosion of cathodes by graphite, in particular in the end zones thereof.
  • the object of the invention is to provide a graphite cathode whose service life is increased by limiting the erosion that occurs at ends.
  • the cathode in graphite is in one piece and its electrical resistivity is heterogeneous along its longitudinal axis, this resistivity being higher in the zones cathode end than in the central area of the cathode, the difference resistivity in the end zones and in the central zone of the cathode being obtained by a different heat treatment in these different zones during the graphitization operation, the end zones being at one temperature lower than that of the central zone.
  • the average resistivity of the product will remain compatible with a optimized operation of the electrolysis tank.
  • the highest resistivity in the cathode end zones channels the current lines to the center of the tank. Because of this, the high current densities usually recorded to the output of the cathode bars are attenuated, inhibiting thus the erosion mechanism in these areas. The life of the tank is therefore increased.
  • the cathode end areas can be considered as located between approximately 0 and 800 mm from each end.
  • the cathode end zones are brought to a temperature of the order from 2,200-2,500 ° C, while the central zone is brought to a temperature of the order of 2,700 to 3,000 ° C.
  • the difference of heat treatment in the end zones and in the central zone of the cathode is obtained by limiting the thermal insulation of the graphitization furnace and / or by having thermal drains in the end zones of the cathodes, to increase heat losses.
  • the difference in treatment thermal in the end zones and in the central zone of the cathode is obtained by creating, during the graphitization operation, modifications local current lines and, therefore, the resulting Joule effect.
  • the difference of heat treatment between the end zones and the central zone is obtained by modulating the resistivity of the resistor grain between two cathodes and / or by having thermal drains in the end zones.
  • FIGS 2 to 4 show an Acheson type oven 6, in which a number of cathodes 3 are arranged parallel to each other others, in several rows, with interposition between the different cathodes of a resistor grain 7.
  • This resistor grain can be constituted, for example by carbon or coke granules.
  • the assembly is arranged inside a heat-insulating grain 8. Electric energy is injected inside the oven, to perform the graphitization operation, the heating resulting from the effect Joule.
  • the streamlines are perpendicular to the axis of the cathodes 3.
  • the resistivity of the resistor grain is higher in the zones 9 corresponding to the end zones of the cathodes 3, that that of this grain resistor in zone 10 corresponding to the central part cathodes. It is also possible to reduce the thickness of the grain insulation 8 in the end areas of the cathodes, to promote the phenomenon of limitation of the graphitization temperature in these areas end by heat loss.
  • FIG. 5 represents a longitudinal oven 11 in which several cathodes 3 are arranged end to end, with interposition between two cathodes adjacent to a graphitization joint 12.
  • the graphitization joints are as weak as possible to avoid unwanted heating at the junction between the cathodes.
  • heat losses materialized by arrows are created in the end zones of the cathodes, by providing a smaller thickness of insulation 8, and / or the presence of thermal drains which can be made of graphite and positioned perpendicular to the cathodes, facing the areas to be cooled.
  • the invention provides a great improvement to the existing technique by providing a cathode of traditional structure, and obtained by known means, having a higher resistivity in its end zones than in its central zone, thus reducing the current density in the cathode at its ends, and increase resistance to erosion in these areas end.

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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)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)

Claims (5)

  1. Graphitkathode für die Elektrolyse von Aluminium, die eine verbesserte Erosionsbeständigkeit aufweist,
    dadurch gekennzeichnet, daß sie als Monoblock ausgebildet ist und daß ihr spezifischer elektrischer Widerstand entlang ihrer Längsachse nicht gleichförmig ist, wobei dieser Widerstand in den Endbereichen der Kathode (3) höher als in ihrem Mittelbereich ist, wobei der Unterschied hinsichtlich der Widerstände in den Endbereichen und im Mittelbereich der Kathode (3) durch eine unterschiedliche Wärmebehandlung in diesen verschiedenen Bereichen beim Vorgang des Graphitisierens erhalten wird, indem sich die Endbereiche auf einer Temperatur befinden, die niedriger als diejenige des Mittelbereichs ist.
  2. Graphitkathode nach Anspruch 1,
    dadurch gekennzeichnet, daß im Verlauf des Vorgangs des Graphitisierens die Endbereiche der Kathode (3) auf eine Temperatur in der Größenordnung von 2200 bis 2500 °C gebracht werden, während der Mittelbereich auf eine Temperatur in der Größenordnung von 2700 bis 3000 °C gebracht wird.
  3. Verfahren zur Herstellung einer Graphitkathode nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß es darin besteht, einen Unterschied in der Wärmebehandlung in den Endbereichen und im Mittelbereich der Kathode (3) herbeizuführen, indem man die Wärmedämmung (8) des Graphitisierungsofens (11) begrenzt und/oder Wärmesenken gegenüber von den Endbereichen der Kathoden anordnet, um die Wärmeverluste zu erhöhen.
  4. Verfahren zur Herstellung einer Graphitkathode nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß es darin besteht, den Unterschied in der Wärmebehandlung in den Endbereichen und im Mittelbereich der Kathode (3) zu bewirken, indem beim Vorgang des Graphitisierens örtliche Modifikationen der Stromlinien und infolgedessen der daraus resultierenden Jouleschen Wärme erzeugt werden.
  5. Verfahren zur Herstellung einer Graphitkathode nach Anspruch 4,
    dadurch gekennzeichnet, daß, in dem Fall, in dem der Vorgang des Graphitisierens gleichzeitig für mehrere Kathoden (3) durchgeführt wird, die parallel zueinander im Inneren eines Ofens (6), wie z.B. vom Acheson-Typ, angeordnet sind, in dem die Kathoden (3) durch eine Packung aus Resistorkornmaterial (7), wie z.B. Kohlenstoff- oder Koksgranulat voneinander getrennt sind, der Unterschied in der Wärmebehandlung zwischen den Endbereichen und dem Mittelbereich der Kathode (3) durch Modulieren des spezifischen elektrischen Widerstandes des Resistorkornmaterials zwischen zwei Kathoden und/oder Anordnen von Wärmesenken gegenüber von den Endbereichen erhalten wird.
EP00901691A 1999-02-02 2000-02-01 Graphit-kathode für die elektrolyse von aluminium Expired - Lifetime EP1151150B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9901320 1999-02-02
FR9901320A FR2789091B1 (fr) 1999-02-02 1999-02-02 Cathode graphite pour l'electrolyse de l'aluminium
PCT/FR2000/000232 WO2000046426A1 (fr) 1999-02-02 2000-02-01 Cathode graphite pour l'electrolyse de l'aluminium

Publications (2)

Publication Number Publication Date
EP1151150A1 EP1151150A1 (de) 2001-11-07
EP1151150B1 true EP1151150B1 (de) 2004-05-19

Family

ID=9541620

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00901691A Expired - Lifetime EP1151150B1 (de) 1999-02-02 2000-02-01 Graphit-kathode für die elektrolyse von aluminium

Country Status (18)

Country Link
US (1) US6627062B1 (de)
EP (1) EP1151150B1 (de)
JP (1) JP2002538293A (de)
CN (1) CN1272471C (de)
AT (1) ATE267277T1 (de)
AU (1) AU776902B2 (de)
BR (1) BR0007917A (de)
CA (1) CA2361610C (de)
DE (1) DE60010861T2 (de)
ES (1) ES2218108T3 (de)
FR (1) FR2789091B1 (de)
IS (1) IS2480B (de)
MX (1) MXPA01007830A (de)
NO (1) NO20013775L (de)
PL (1) PL195085B1 (de)
RU (1) RU2245395C2 (de)
WO (1) WO2000046426A1 (de)
ZA (1) ZA200106312B (de)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10164011C1 (de) * 2001-12-28 2003-05-08 Sgl Carbon Ag Verfahren zum Graphitieren von Kathodenblöcken
DE10164013C1 (de) * 2001-12-28 2003-04-03 Sgl Carbon Ag Verfahren zum Graphitieren von Kathodenblöcken
DE10164012C1 (de) * 2001-12-28 2003-04-30 Sgl Carbon Ag Verfahren zur kontinuierlichen Graphitierung
DE10164010C1 (de) * 2001-12-28 2003-04-30 Sgl Carbon Ag Verfahren zur Herstellung von Kathodenblöcken
DE10164008C1 (de) * 2001-12-28 2003-04-30 Sgl Carbon Ag Graphitierte Kathodenblöcke
DE10164009B4 (de) * 2001-12-28 2005-04-07 Sgl Carbon Ag Verfahren zur Herstellung von Kathodenblöcken
DE10164014C1 (de) * 2001-12-28 2003-05-22 Sgl Carbon Ag Verfahren zum Graphitieren von Kathodenblöcken
DE10261745B3 (de) * 2002-12-30 2004-07-22 Sgl Carbon Ag Kathodensystem zur elektrolytischen Aluminiumgewinnung
FR2861090B1 (fr) * 2003-10-17 2005-12-23 Sgl Carbone Ag Cathode pour l'electrolyse de l'aluminium, son procede de fabrication et utilisation de celle-ci
RU2443623C1 (ru) * 2010-10-14 2012-02-27 Закрытое акционерное общество "Институт новых углеродных материалов и технологий" (ЗАО "ИНУМиТ") Способ получения графитированного материала с повышенной абразивной стойкостью
CN102234820B (zh) * 2011-08-04 2013-03-20 中国铝业股份有限公司 一种减少铝电解槽铝液水平电流的方法
EP2650404B1 (de) 2012-04-12 2018-01-10 SGL CFL CE GmbH Elektrolysezelle, insbesondere zur Herstellung von Aluminium
CN110184627B (zh) * 2019-05-10 2020-11-06 中国铝业股份有限公司 一种铝电解用定向导磁阴极钢棒

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1029122A (en) 1910-02-10 1912-06-11 Electrode Company Of America Graphitizing electrodes.
CA968744A (en) * 1970-12-12 1975-06-03 Kurt Lauer Cathode for the winning of aluminum
DE2105247C3 (de) 1971-02-04 1980-06-12 Schweizerische Aluminium Ag, Zuerich (Schweiz) Ofen für die Schmelzflußelektrolyse von Aluminium
CH620948A5 (de) * 1976-05-13 1980-12-31 Alusuisse
DE3327230A1 (de) 1983-07-28 1985-02-07 Sigri Elektrographit Gmbh, 8901 Meitingen Auskleidung fuer elektrolysewanne zur herstellung von aluminium

Also Published As

Publication number Publication date
FR2789091B1 (fr) 2001-03-09
CA2361610C (fr) 2004-07-06
IS2480B (is) 2008-12-15
JP2002538293A (ja) 2002-11-12
PL350236A1 (en) 2002-11-18
EP1151150A1 (de) 2001-11-07
RU2245395C2 (ru) 2005-01-27
NO20013775D0 (no) 2001-08-01
MXPA01007830A (es) 2003-06-04
AU2301200A (en) 2000-08-25
ZA200106312B (en) 2003-02-26
CN1272471C (zh) 2006-08-30
ES2218108T3 (es) 2004-11-16
NO20013775L (no) 2001-09-28
IS6026A (is) 2001-07-27
PL195085B1 (pl) 2007-08-31
BR0007917A (pt) 2001-11-27
CA2361610A1 (fr) 2000-08-10
CN1342219A (zh) 2002-03-27
AU776902B2 (en) 2004-09-23
DE60010861D1 (de) 2004-06-24
ATE267277T1 (de) 2004-06-15
US6627062B1 (en) 2003-09-30
WO2000046426A1 (fr) 2000-08-10
FR2789091A1 (fr) 2000-08-04
DE60010861T2 (de) 2004-11-04

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