EP0082096B1 - Eléments cathodiques flottants, à base de réfractaire électroconducteur, pour la production d'aluminium par électrolyse - Google Patents

Eléments cathodiques flottants, à base de réfractaire électroconducteur, pour la production d'aluminium par électrolyse Download PDF

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Publication number
EP0082096B1
EP0082096B1 EP82420176A EP82420176A EP0082096B1 EP 0082096 B1 EP0082096 B1 EP 0082096B1 EP 82420176 A EP82420176 A EP 82420176A EP 82420176 A EP82420176 A EP 82420176A EP 0082096 B1 EP0082096 B1 EP 0082096B1
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EP
European Patent Office
Prior art keywords
aluminium
cathodic
floating
tank
density
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
Application number
EP82420176A
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German (de)
English (en)
French (fr)
Other versions
EP0082096A1 (fr
Inventor
Maurice Keinborg
Philippe Varin
Yves Bertaud
Michel Leroy
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.)
Rio Tinto France SAS
Original Assignee
Aluminium Pechiney SA
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Publication date
Application filed by Aluminium Pechiney SA filed Critical Aluminium Pechiney SA
Publication of EP0082096A1 publication Critical patent/EP0082096A1/fr
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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 floating cathode elements, in electroconductive refractory, such as titanium diboride, intended for the production of aluminum by electrolysis, according to the Hall-Héroult process.
  • the cathode In Hall-Héroult cells, the cathode is universally made up of juxtaposed carbon blocks, in which metal bars are sealed, themselves connected to conductors ensuring the electrical connection with the next tank in the series. In operation, the cathode is permanently covered with a layer of liquid aluminum about twenty centimeters thick.
  • electroconductive refractories belong to the class formed by borides, carbides and nitrides of metals of groups 4A, 5A and 6A but, until now, research has mainly focused on titanium diborides TiB 2 and zirconium ZrB 2 .
  • titanium boride has a resistivity of 60 ⁇ cm - and zirconium boride of 74 ⁇ cm - 2 and 2.5 times that of liquid aluminum, respectively, but more than 5000 times that of electrolysis bath which is around 450,000 ⁇ cm. They are perfectly wetted by liquid aluminum and sufficiently inert with respect to the molten cryolite.
  • patent FR-A-2 471 425 (ALU-SUISSE) describes cathodic elements made of titanium diboride in the form of grainy or in pieces, poured in bulk on the bottom of the tank, and covered with a thickness of liquid aluminum at least equal to 2 mm.
  • this cathode may include an intermediate carbon support placed on the basic carbon substrate, and supporting the bed of particles of titanium diboride.
  • removable cathode elements comprising an inert intermediate support and active elements in electroconductive refractory, such as TiB 2 , integral but separable from said support, the assembly formed by the inert intermediate support and the active elements having a density greater than the density of liquid aluminum at the temperature of electrolysis.
  • the present invention aims to eliminate these drawbacks. It is based on elements in electrically conductive refractories wettable by liquid aluminum and, in particular, based on titanium diboride, not directly linked to the cathode substrate, guided and having a limited degree of freedom, in the vertical direction, and that floating is maintained at the interface between the electrolysis bath and the aluminum produced, whatever the fluctuations of this interface during the electrolysis process, by making them support by an inert intermediate support of lower density to that of liquid aluminum.
  • these elements are removable so as to be put in place and replaced without interrupting the electrolysis, with possible intermediate passage in a chamber for controlled preheating or cooling, with a controlled atmosphere or not.
  • the present invention relates to these floating cathode elements and the electrolytic cells for the production of aluminum comprising these elements.
  • the active cathode element made of TiB 2 (1) is formed by a flat or slightly convex head and a tail (2) which is positioned in the orifices (3) of an inert intermediate support (4) in graphite.
  • the average density of the cathode assembly thus formed is lower than that of liquid aluminum.
  • the heads of the pads (1) are, in normal operation, in the vicinity of the aluminum sheet-electrolyte interface.
  • the cathode element (1) can rest directly on the orifice (3) or be provided with a boss (5) or fins (6) which provide an interval favoring the flow of the liquid aluminum progressively of its production (fig. 2 and 3).
  • Figures 4 and 5 show another embodiment in which the floating cathode element (7) is anchored to the cathode substrate (8) by studs (9).
  • the head (10) of the anchoring stud cooperates with a recess (11) of the intermediate support (7) to ensure a stop which limits its upward stroke.
  • the active cathode elements (12) consist of sections of split tubes (13) and threaded on a rail (14), leaving between them sufficient free space for the flow of aluminum produced. These tubes can have a circular, square or other section.
  • the mass ratio of graphite / mass of TiB 2 is fixed so that the average density of the assembly is less than the density of the electrolyte so that the floating cathode element is , normally in the upper stop.
  • the stroke of the floating element determined by the position of the stopper and the height of the anchoring stud, must be at least equal to the variations in height of the sheet of liquid aluminum. during electrolysis and racking of metal.
  • the active TiB 2 elements (12) must exceed the interface (15) by at least 10 millimeters.
  • FIG. 6 shows another alternative embodiment in which the floating cathode element consists of a graphite plate (17) coated with thin-coated titanium diboride (18) produced by chemical phase deposition steam or plasma torch projection.
  • the floating plate is retained at the bottom by a dense block (19) of refractory concrete, resistant to the action of liquid aluminum (16) resting on the cathode substrate (9).
  • the dense block (19) is provided with channels (20) to ensure the circulation of aluminum and the passage of current.
  • the floating structure may include guide means such as the rollers (21) which cooperate, for example, with the support legs (22) .
  • These rollers can be made, for example, of TiBz or silicon nitride or silicon and aluminum oxynitride (Sialon).
  • the refractory support (24) is fully embedded in the metal.
  • the perforated support (25), which holds the pads (1) of TiBz has a density lower than the density of the electrolysis bath: it is for example graphite, possibly protected by a thin deposit of a refractory such as titanium diboride or Sialon.
  • the perforated support + TiBz pads assembly If the average density of the perforated support + TiBz pads assembly is lower than that of the bath, the perforated support remains permanently in the top stop. If this average density is between that of the bath and that of the metal, the perforated support follows the variations in level of the metal during the electrolysis.
  • FIG. 9 gives the construction detail of the dense refractory support (24) of FIG. 8 with high (25) and low (26) stops.
  • One of its faces may have a removable wall (27). The establishment or removal of such walls makes it possible to direct and control the circulation of the metal and the bath under the effect of electromagnetic forces.
  • FIGS 10 to 13 show the third implementation variant according to which each TiBz element is associated with a graphite float.
  • the cathode active element made of TiB 2 (30) is encased in a graphite ring (31).
  • An intermediate support (32) made of inert material acts as a high stop for the graphite ring (31). This intermediate support comes to bear on the cathode substrate by feet or supports not shown, which do not call for any particular comment.
  • the TiBz element (33) is a plate fixed by the screw (34) to the graphite float (35).
  • the fixing can be carried out by any other equivalent means.
  • the graphite float (36) has a well (37) closed in its lower part and filled with liquid aluminum.
  • the TiBz elements (38) are supported on the graphite float by fins or ribs (39).
  • the “bowl” shape of the element (40) in FIG. 13 promotes the gathering of the liquid aluminum produced and its flow through the channels (41
  • the ratio: mass of the TiB 2 element / mass of the graphite element must be determined, taking into account the density of both, to obtain a resulting average density, either between 2.3 and 2.2, or less than 2.2 and preferably 2.1, in the usual temperature range of 930 to 960 ° C.
  • density values would have to be adapted if an electrolyte having a somewhat different density were used as a result of a modified composition.
  • the present invention offers numerous advantages which make it possible to transpose to the industrial stage a technique which had hitherto remained experimental. .
  • the TiB 2 studs, individually, and above all, grouped together, can be easily replaced and their floating nature makes them less vulnerable to mechanical operating shocks: in the case of FIG. 8, for example, in the event of a shock to when installing or removing an anode, the floating elements (25) can disappear in the dense concrete block (24) ensuring anchoring.
  • the height of the underlying metal can be maintained at a value sufficient to reduce the horizontal currents and the corresponding electromagnetic disturbances to an acceptable value, and the periodic removal of the metal can be carried out as in a conventional electrolysis cell.
  • the alumina sludge which is likely to form, settles at the bottom of the crucible, under the metal, thus sparing the surface of the floating elements on the metal. This device makes it easy to transform conventional tanks into tanks with TiB 2 elements.
  • the invention makes it possible to envisage a new design of electrolytic cells, in which the entire lining, including the bottom, is made of refractory, non-conductive material, and the cathode current is collected. in the sheet of liquid aluminum by a conductor located at the top of the electrolysis cell.
  • FIGS. 14 and 15 there is shown the diagram of such a tank, with the external metal box (42), the thermally insulating lining (43), the refractory and electrically insulating lining (44), the aluminum sheet.
  • li quide (45); the cathode element (46), object of the invention, is of the type described in FIG. 7, the electrolyte (47) the anodes (48) and the anode current inlets (49) (spider).
  • the cathodic current is collected by an element (50) comprising a vertical collector (51) which is a good electrical conductor, possibly protected from corrosion by an insulating sheath (52) and the end of which is capped by a TiB 2 cap (53). .

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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)
  • Ceramic Products (AREA)
EP82420176A 1981-12-11 1982-12-09 Eléments cathodiques flottants, à base de réfractaire électroconducteur, pour la production d'aluminium par électrolyse Expired EP0082096B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8123780 1981-12-11
FR8123780A FR2518124A1 (fr) 1981-12-11 1981-12-11 Elements cathodiques flottants, a base de refractaire electroconducteur, pour la production d'aluminium par electrolyse

Publications (2)

Publication Number Publication Date
EP0082096A1 EP0082096A1 (fr) 1983-06-22
EP0082096B1 true EP0082096B1 (fr) 1985-08-21

Family

ID=9265204

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82420176A Expired EP0082096B1 (fr) 1981-12-11 1982-12-09 Eléments cathodiques flottants, à base de réfractaire électroconducteur, pour la production d'aluminium par électrolyse

Country Status (19)

Country Link
US (1) US4532017A (ru)
EP (1) EP0082096B1 (ru)
JP (1) JPS58107491A (ru)
AU (1) AU552985B2 (ru)
BR (1) BR8207190A (ru)
CA (1) CA1195950A (ru)
DE (1) DE3265665D1 (ru)
ES (1) ES517933A0 (ru)
FR (1) FR2518124A1 (ru)
GR (1) GR77281B (ru)
HU (1) HU191107B (ru)
IN (1) IN158855B (ru)
NO (1) NO157508C (ru)
NZ (1) NZ202697A (ru)
OA (1) OA07274A (ru)
PL (1) PL134338B1 (ru)
SU (1) SU1205779A3 (ru)
YU (1) YU268982A (ru)
ZA (1) ZA829064B (ru)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4526669A (en) * 1982-06-03 1985-07-02 Great Lakes Carbon Corporation Cathodic component for aluminum reduction cell
FR2529580B1 (fr) * 1982-06-30 1986-03-21 Pechiney Aluminium Cuve d'electrolyse pour la production d'aluminium, comportant un ecran conducteur flottant
CH651855A5 (de) * 1982-07-09 1985-10-15 Alusuisse Festkoerperkathode in einer schmelzflusselektrolysezelle.
CH654335A5 (de) * 1983-03-11 1986-02-14 Alusuisse Zelle zur raffination von aluminium.
AU2713684A (en) * 1983-04-26 1984-11-01 Aluminium Company Of America Electrolytic cell
US4622111A (en) * 1983-04-26 1986-11-11 Aluminum Company Of America Apparatus and method for electrolysis and inclined electrodes
US4596637A (en) * 1983-04-26 1986-06-24 Aluminum Company Of America Apparatus and method for electrolysis and float
US4664760A (en) * 1983-04-26 1987-05-12 Aluminum Company Of America Electrolytic cell and method of electrolysis using supported electrodes
US4808304A (en) * 1983-10-19 1989-02-28 Deal Troy M Apparatus for the dewatering of phosphate slimes
US4631121A (en) * 1986-02-06 1986-12-23 Reynolds Metals Company Alumina reduction cell
JPH0628943Y2 (ja) * 1988-08-10 1994-08-03 多摩川精機株式会社 巻線機におけるニードル揺動機構
US4919782A (en) * 1989-02-21 1990-04-24 Reynolds Metals Company Alumina reduction cell
US5129998A (en) * 1991-05-20 1992-07-14 Reynolds Metals Company Refractory hard metal shapes for aluminum production
US5486278A (en) * 1993-06-02 1996-01-23 Moltech Invent S.A. Treating prebaked carbon components for aluminum production, the treated components thereof, and the components use in an electrolytic cell
US5472578A (en) * 1994-09-16 1995-12-05 Moltech Invent S.A. Aluminium production cell and assembly
US5753382A (en) * 1996-01-10 1998-05-19 Moltech Invent S.A. Carbon bodies resistant to deterioration by oxidizing gases
US6071388A (en) * 1998-05-29 2000-06-06 International Business Machines Corporation Electroplating workpiece fixture having liquid gap spacer
GB2371055A (en) * 2001-01-15 2002-07-17 Innovation And Technology Alum Anode for electrolysis of aluminium
RU2454490C1 (ru) * 2010-11-02 2012-06-27 Общество с ограниченной ответственностью "Легкие металлы" Электролизер для производства алюминия
DE102011111331A1 (de) * 2011-08-23 2013-02-28 Esk Ceramics Gmbh & Co. Kg Titandiborid-Granulate als Erosionsschutz für Kathoden
AU2014334447A1 (en) * 2013-10-07 2016-05-19 Electro-Kinetic Solutions Inc. Method and apparatus for treating tailings using an AC voltage with a DC offset

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3407132A (en) * 1965-06-16 1968-10-22 Minnesota Mining & Mfg Floating anode
GB1169012A (en) * 1965-10-21 1969-10-29 Montedison Spa Furnace and Process for Producing, in Fused Bath, Metals from their Oxides, and Electrolytic Furnaces having Multiple Cells formed by Horizontal Bipolar Carbon Electrodes
NO764014L (ru) * 1975-12-31 1977-07-01 Aluminum Co Of America
CH635132A5 (de) * 1978-07-04 1983-03-15 Alusuisse Kathode fuer einen schmelzflusselektrolyseofen.
US4338177A (en) * 1978-09-22 1982-07-06 Metallurgical, Inc. Electrolytic cell for the production of aluminum
US4177128A (en) * 1978-12-20 1979-12-04 Ppg Industries, Inc. Cathode element for use in aluminum reduction cell
US4349427A (en) * 1980-06-23 1982-09-14 Kaiser Aluminum & Chemical Corporation Aluminum reduction cell electrode
CH648870A5 (de) * 1981-10-23 1985-04-15 Alusuisse Kathode fuer eine schmelzflusselektrolysezelle zur herstellung von aluminium.

Also Published As

Publication number Publication date
OA07274A (fr) 1984-04-30
GR77281B (ru) 1984-09-11
ES8402365A1 (es) 1984-01-16
ES517933A0 (es) 1984-01-16
NO157508C (no) 1988-03-30
NO824167L (no) 1983-06-13
NZ202697A (en) 1986-02-21
SU1205779A3 (ru) 1986-01-15
JPS58107491A (ja) 1983-06-27
PL239350A1 (en) 1983-06-20
AU9145982A (en) 1983-06-16
AU552985B2 (en) 1986-06-26
BR8207190A (pt) 1983-10-11
JPS6127474B2 (ru) 1986-06-25
US4532017A (en) 1985-07-30
CA1195950A (fr) 1985-10-29
YU268982A (en) 1985-03-20
FR2518124B1 (ru) 1984-02-17
ZA829064B (en) 1983-09-28
EP0082096A1 (fr) 1983-06-22
IN158855B (ru) 1987-02-07
FR2518124A1 (fr) 1983-06-17
HU191107B (en) 1987-01-28
DE3265665D1 (en) 1985-09-26
PL134338B1 (en) 1985-08-31
NO157508B (no) 1987-12-21

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