EP0144371B1 - Barre cathodique comportant une semelle metallique, pour cuves d'electrolyse hall-heroult - Google Patents

Barre cathodique comportant une semelle metallique, pour cuves d'electrolyse hall-heroult Download PDF

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Publication number
EP0144371B1
EP0144371B1 EP84902015A EP84902015A EP0144371B1 EP 0144371 B1 EP0144371 B1 EP 0144371B1 EP 84902015 A EP84902015 A EP 84902015A EP 84902015 A EP84902015 A EP 84902015A EP 0144371 B1 EP0144371 B1 EP 0144371B1
Authority
EP
European Patent Office
Prior art keywords
electrolytic cell
cell according
cathode
sole
metal
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
EP84902015A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0144371A1 (fr
Inventor
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
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from FR8308334A external-priority patent/FR2546184B1/fr
Application filed by Aluminium Pechiney SA filed Critical Aluminium Pechiney SA
Priority to AT84902015T priority Critical patent/ATE30053T1/de
Publication of EP0144371A1 publication Critical patent/EP0144371A1/fr
Application granted granted Critical
Publication of EP0144371B1 publication Critical patent/EP0144371B1/fr
Expired legal-status Critical Current

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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

Definitions

  • the invention relates to the construction of electrolytic cells for the production of aluminum by the Hall-Héroult process. It relates more particularly to an electrolysis tank in which each cathode bar comprises a metal soleplate, intended to increase the passage section and to standardize the distribution of the cathode current.
  • the cathode of a Hall-Héroult electrolysis tank is formed by the juxtaposition of a set of carbonaceous blocks, provided, at their lower base, with one (or sometimes two) open groove (s) in which are sealed, generally by casting, steel bars of square, rectangular or circular section, on which are connected the connecting conductors between the successive tanks forming a series.
  • the steel bars used for the extraction of the cathode current therefore offer a limited contact surface with the carbon, which causes a significant voltage drop at the carbon / cast iron interface.
  • the object of the present invention is to increase substantially (more than 10%) the section of steel available for the evacuation of the cathode current, and the contact surface between the carbon and the cathode conductors. It consists, in an electrolytic cell of the type defined in the preamble of claim 1, to provide each cathode bar with a metal sole, constituted by a metal sheet, welded to the cathode bar before the establishment of the carbonaceous block in the tank, to ensure the passage of electric current and the electrical contact between said soleplate and the base of the carbonaceous block being ensured by at least one layer of elastic material conducting electricity.
  • the sole must have a thickness at least equal to 4 mm, and preferably at least equal to 10 mm.
  • a continuous steel screen can be placed under the soleplate, in electrical contact with the soleplate, which prevents infiltration of liquid aluminum and molten cryolite, which appreciably increases the service life of the electrolysis tank.
  • Figure 1 relates to the prior art.
  • FIG. 2 to 15 illustrate the implementation of the invention.
  • Figure 1 shows the classic arrangement of a carbonaceous cathode block (1) in which the bar (2A) is sealed by cast iron (3).
  • the bar is flush with the base of the carbon block.
  • the bar (2B) in an alternative embodiment can more or less exceed the base plane of the carbonaceous block (3).
  • the successive cathode blocks are most often assembled by a joint (4) made of carbonaceous paste.
  • FIG. 2 illustrates a first embodiment of the invention.
  • two thick sheets of mild steel (5) were welded connected to the base of the carbon block (1) by a layer of electrically conductive elastic material (6).
  • the steel soleplate (5) can consist of a steel-copper colamine, the copper-colored face (5A) being in contact with the carbonaceous block (1) via the elastic conductive layer ( 6).
  • the thickness of the copper layer (5A) must be greater than a minimum value, which can be estimated at around 5% of the steel layer, corresponding to the solubility of the copper. in steel at 900-950 ° C, so that the entire copper layer does not disappear by diffusion in the solid state in the steel.
  • the malleability of hot copper facilitates the establishment of good contact with the cathode block and can, if necessary, partially compensate for deformations of the steel soleplate.
  • Figure 3 shows the four stages 3a, 3b, 3c, 3d of the procedure used to carry out the assembly of Figure 2.
  • Figure 3a shows the first step
  • the carbon block (1) having been turned over so that the groove (7) faces upwards, the cathode bar (2) is sealed by casting iron (3).
  • Figure 3b shows the second step
  • an elastic, electrically conductive layer (6) is placed on the upper face of the inverted block: it is advantageous to use a carbon or graphite felt, or a laminated graphite sheet, or another complex formed by bonding a strip of carbon felt or graphite and a strip of laminated graphite.
  • RVG graphite felts or “Papyex” (R) (trademarks registered by the Company “Le Carbone-Lorraine”).
  • Figure 3c shows the third step
  • the sole (5) consists of two thick steel sheets, which are applied strongly, by pressing, to the elastic link layer (6) on the elastic connection layer (6).
  • a steel flange is thus produced electrically connected to the cathode bar.
  • the thickness of the sole is at least equal to 4 mm and, preferably, at least equal to 10 mm and generally of the order of 10 to 15 mm.
  • the cross-section of the cathode bar can be, for example, 160 x 120 mm.
  • Figure 3d shows the cathode carbon block returned to normal position by inversion.
  • Figure 4 shows a variant of the invention where the steel base is located astride two carbon cathode blocks, and in electrical contact with these two blocks.
  • Figure 5 shows that when performing the assembly, it is preferable to provide a slight clearance between the flanges (5) of two adjacent blocks (1) and (1 ') so that when the normal operating temperature is reached, and due to the greater expansion of the steel base compared to the carbonaceous block, the edges of the two adjacent flanges (5) and (5 '), are in contact with a pressure just sufficient to ensure a weld to hot of these edges between them, without this pressure being excessive to the point of causing deformation of the soles, detrimental to the electrical contact between carbonaceous blocks and steel soles.
  • the blanks of the bevels of (5) and (5 ') may be parallel to each other (5A) or not (5B).
  • the value of the clearance (9) necessary for mounting or installation depends on the exact nature of the carbonaceous block: based on anthracite, or semi-graphite or semi-graphitized or graphite, and on the exact dimension of the blocks and footings , as well as the nature and thickness of the joint between carbonaceous blocks: blocks glued together or separated by a small joint (4) of pot lining. Generally, this game will be defined by an e / L ratio of the order of 1 to 2%.
  • Figure 6 shows the mounting detail of the sealing strips (10).
  • the upper strip (10A) is welded for example on the sheet (5) and the lower strip (10B) is welded on the sheet (5 ') so that, during the first heating, they can slide freely and take their definitive place.
  • a lower porosity graphite piece (12) can be placed at the bottom of the joint (4) which improves the seal of the joint (4 ) and reduces the risk of infiltration of molten cryolite when the electrolysis tank is started.
  • Figure 7 shows another alternative embodiment of the joint between the flanges (5) and (5 ') of adjacent cathode blocks (1) and (1').
  • a flexible joint (14) preferably electrically conductive and compressible, such as graphite braid, or a tube thin-walled metal (thickness less than half the thickness of the sole, (5) or (5 '), resting freely between the strips 10A and 10B.
  • FIG. 8 represents another variant, in which the flexible carbon joint (14) is replaced by a deformable tube (15), welded beforehand to at least one of the flanges (5) or (5 '), which absorbs the expansion effects and which can be filled with an inert pulverulent material (19), to limit internal hot oxidation.
  • FIGS 9 and 10 illustrate the implementation of the invention in the case of carbon blocks (1) provided with two parallel cathode bars (2C and 2D), an arrangement which is sometimes encountered in order to increase the surface contact with the carbon block.
  • the two bars 2C, 2D were sealed simultaneously by casting iron (3), the thickness (e) of the iron plate between the two bars preferably being less than or equal to the difference in the ratings h o and h 1 (e ⁇ h o - h i ).
  • the soleplate (5) can be made of single or mixed steel-copper sheet steel as described above.
  • the two cathode bars 2C, 2D were individually sealed, then connected by welding with a sheet (21) preformed in a vault, so as to obtain, when hot, good electrical contact with the central part of the carbonaceous block. via the elastic conductive layer (6).
  • the metal soleplate is in contact with the base of the carbon blocks by means of the elastic material (6) over at least 20% of the surface of this base.
  • a screen (26) under the base of the carbon blocks constituting the cathode of the electrolytic cell and in which the cathode bars are sealed, this screen extending at least over the entire space located below the cathode (fig. 11). It consists of at least one continuous sheet of steel, at least half of the surface of which consists of a part having at least 5 mm, and preferably 8 to 12 mm thick, and which comprises at least one zone. deformable absorbing stresses due to temperature differences between the central part, located directly above the cathode, and the less hot peripheral part. To avoid any risk of electrochemical corrosion, it is then preferable to put the metal soleplate (5) in electrical contact with the screen (26).
  • the electrical connection between the sole (5) and the screen (26) can be ensured by welding, for example, by a continuous or discontinuous bead between at least one edge of the sole and the continuous screen. It can also be ensured by the fusion of a brazing alloy previously disposed between the sole and the continuous screen, the points of solidus and liquidus of this alloy being suitably chosen.
  • FIG. 12 shows an embodiment of this principle, according to which the sole (5) of each cathode bar (2) is placed directly on the continuous screen (26) of thick steel, to which it is connected by solder (16) or by welding (17).
  • the advantage of this arrangement is that the continuous thick steel screen (26) is, at all points, at the electrical potential of the cathode bars, which eliminates any effect of electrochemical cell generating rapid corrosion.
  • the thickness of the screen is at least 5 mm, and preferably between 8 and 12 mm.
  • the sole (5) has a thickness at least equal to 4 mm and, preferably, at least equal to 10 mm.
  • Figure 12 shows how this device can be implemented during the construction of the tank.
  • the cathode bar (2) was put in place and sealed with cast iron (3) in each cathode block (1).
  • a sole (5) whose length is at most equal and, in practice slightly less than the distance between two successive bars.
  • the block is then placed on the screen (26), resting on the insulating layer (20), and welded at (9), preferably by a continuous cord, so as to ensure good electrical contact.
  • the layers (24) and (25) are insulating and refractory bricks, arranged on the bottom (27) of the casing of the electrolysis tank.
  • the optimal brazing compositions for implementing the invention comprise at least 50% of a first metal chosen from aluminum, copper, zinc, the remainder being at least a second metal chosen from manganese, nickel, vanadium, beryllium, silicon, tin and titanium, as well as aluminum and copper if the first metal is not copper or aluminum.
  • compositions no. 1, 3, 6 and 7 are particularly suitable in industrial practice. Some are fragile and can be ground to the desired fineness, others must be treated in a known manner, by spraying in the liquid state.
  • the solder can be used in the form of a thin, laminated sheet, introduced during assembly between the sole and the screen.
  • a reducing metal with respect to iron oxide (scale) which most often covers the steel plates used to constitute the sole or the screen (metal such as AI and / or Si) dispenses with using any other stripper to promote spreading of the solder when it passes into the liquid state.
  • the sole (5) and the screen (26) in a single part, constituted by a thick steel sheet (22), as shown in the figures. 13 and 14, which may be provided with seals or deformable zones, capable of withstanding thermal expansions, for example the tube (15) of FIG. 2.
  • the thickness of the screen may be between 10 and 20 mm.
  • the bars (2) are positioned on the screen (22), then connected by a weld bead (23). After which, the cathode blocks (1) are put in place, the sealing being ensured by carbonaceous paste (13).
  • the connection can also be made by a solder (16).
  • Fig. 14 shows another method of assembly, according to which the cathode bars (2) are no longer arranged directly above the axis of the block (1), but straddling two blocks adjacent to the vertical line of the joint between these two blocks.
  • the advantage of this arrangement is that the carbonaceous paste (4) ensuring the sealing between the blocks (1) and the bars (2) can be injected, hot, in the space separating two adjacent blocks.
  • FIG. 15 very schematically shows the partial cross-section of an electrolytic cell according to the invention, with the external metal box (30), the side soldering (31) in carbonaceous paste, the cathode carbon block (1 ) surmounted by the sheet of liquid aluminum (32), the electrolyte (33) and the anode system (34), the cathode bar (2) made of steel, sealed with cast iron (3), and the soleplate (5) steel, object of the invention. It is noted that the cross section of the cathode bar (2) is reduced in the crossing of the external part of the lining (31) and of the box (30).

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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)
  • Laminated Bodies (AREA)
  • Insulated Conductors (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
EP84902015A 1983-05-16 1984-05-14 Barre cathodique comportant une semelle metallique, pour cuves d'electrolyse hall-heroult Expired EP0144371B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84902015T ATE30053T1 (de) 1983-05-16 1984-05-14 Kathodenstange mit einer metallsohle fuer hallheroult-elektrolyseoefen.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR8308334 1983-05-16
FR8308334A FR2546184B1 (fr) 1983-05-16 1983-05-16 Barre cathodique comportant une semelle metallique pour cuves d'electrolyse hall-heroult
FR8403864 1984-03-02
FR8403864A FR2560613B2 (fr) 1983-05-16 1984-03-02 Perfectionnement aux barres cathodiques comportant une semelle metallique, pour cuves d'electrolyse hall-heroult

Publications (2)

Publication Number Publication Date
EP0144371A1 EP0144371A1 (fr) 1985-06-19
EP0144371B1 true EP0144371B1 (fr) 1987-09-30

Family

ID=26223446

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84902015A Expired EP0144371B1 (fr) 1983-05-16 1984-05-14 Barre cathodique comportant une semelle metallique, pour cuves d'electrolyse hall-heroult

Country Status (15)

Country Link
US (1) US4647356A (enrdf_load_stackoverflow)
EP (1) EP0144371B1 (enrdf_load_stackoverflow)
AU (1) AU569524B2 (enrdf_load_stackoverflow)
CA (1) CA1214752A (enrdf_load_stackoverflow)
DE (1) DE3466561D1 (enrdf_load_stackoverflow)
ES (1) ES288259Y (enrdf_load_stackoverflow)
FR (1) FR2560613B2 (enrdf_load_stackoverflow)
GR (1) GR81586B (enrdf_load_stackoverflow)
IS (1) IS1305B6 (enrdf_load_stackoverflow)
IT (1) IT1173645B (enrdf_load_stackoverflow)
NO (1) NO850095L (enrdf_load_stackoverflow)
NZ (1) NZ208161A (enrdf_load_stackoverflow)
SU (1) SU1349702A3 (enrdf_load_stackoverflow)
WO (1) WO1984004547A1 (enrdf_load_stackoverflow)
YU (1) YU84284A (enrdf_load_stackoverflow)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4912302A (en) * 1987-05-30 1990-03-27 Ngk Insulators, Ltd. Furnace for sintering ceramics, carbon heater used therefor and process for sintering ceramics
AUPO053496A0 (en) * 1996-06-18 1996-07-11 Comalco Aluminium Limited Cathode construction
US5976333A (en) * 1998-01-06 1999-11-02 Pate; Ray H. Collector bar
RU2239007C2 (ru) * 1999-10-13 2004-10-27 Алкоа Инк. Катодный коллекторный стержень для улучшения теплового баланса
NO315090B1 (no) * 2000-11-27 2003-07-07 Servico As Anordninger for å före ström til eller fra elektrodene i elektrolyseceller,fremgangsmåter for fremstilling derav, samt elektrolysecelle forfremstilling av aluminium ved elektrolyse av alumina löst i en smeltetelektrolytt
EP1502589B1 (en) * 2003-07-31 2006-05-31 Emdoka bvba, Drug registration and Marketing Veterinary aqueous injectable suspensions containing florfenicol
RU2270279C1 (ru) * 2004-07-09 2006-02-20 Открытое акционерное общество "Соликамский магниевый завод" Электролизер для получения магния и хлора
EP1927679B1 (en) * 2006-11-22 2017-01-11 Rio Tinto Alcan International Limited Electrolysis cell for the production of aluminium comprising means to reduce the voltage drop
CN104651882A (zh) * 2014-09-29 2015-05-27 贵州航天乌江机电设备有限责任公司 一种铝电解槽阴极组装工艺
DE102016210693A1 (de) * 2016-06-15 2017-12-21 Sgl Cfl Ce Gmbh Kathodenblock aufweisend eine neuartige Nut-Geometrie
NO20180369A1 (en) * 2018-03-14 2019-09-16 Norsk Hydro As Cathode elements for a Hall-Héroult cell for aluminium production and a cell of this type having such elements installed
EP4185737A4 (en) * 2020-09-08 2024-10-23 Versum Materials US, LLC ELECTRODE ATTACHMENT ASSEMBLY, CELL AND METHOD OF USE

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE484041A (enrdf_load_stackoverflow) * 1947-09-05
NL69585C (enrdf_load_stackoverflow) * 1947-09-08
FR1125949A (fr) * 1955-04-30 1956-11-12 Pechiney Perfectionnements dans la confection de la partie inférieure du creuset des cellules d'électrolyse ignée
FR1161632A (fr) * 1956-11-16 1958-09-02 Pechiney Perfectionnements aux cellules d'électrolyse ignée
US3551319A (en) * 1968-09-06 1970-12-29 Kaiser Aluminium Chem Corp Current collector
CH527909A (de) * 1970-05-01 1972-09-15 Alusuisse Aluminium-Elektrolysezelle
JPS56150190A (en) * 1980-01-16 1981-11-20 Agency Of Ind Science & Technol Preparation of composite material by thermite reaction
JPS56150195A (en) * 1980-04-23 1981-11-20 Sumitomo Alum Smelt Co Ltd Cathode furnace bottom for aluminum electrolytic furnace
FR2546183B1 (fr) * 1983-05-16 1985-07-05 Pechiney Aluminium Ecran sous-cathodique comportant des zones deformables, pour les cuves d'electrolyse hall-heroult

Also Published As

Publication number Publication date
IT8420920A1 (it) 1985-11-15
WO1984004547A1 (fr) 1984-11-22
EP0144371A1 (fr) 1985-06-19
US4647356A (en) 1987-03-03
NZ208161A (en) 1988-03-30
ES288259U (es) 1985-12-16
FR2560613A2 (fr) 1985-09-06
YU84284A (en) 1987-12-31
IS1305B6 (is) 1987-11-25
GR81586B (enrdf_load_stackoverflow) 1984-12-11
AU2963884A (en) 1984-12-04
DE3466561D1 (en) 1987-11-05
ES288259Y (es) 1986-07-16
CA1214752A (fr) 1986-12-02
FR2560613B2 (fr) 1987-03-27
IT1173645B (it) 1987-06-24
NO850095L (no) 1985-01-09
AU569524B2 (en) 1988-02-04
IT8420920A0 (it) 1984-05-15
IS2911A7 (is) 1984-07-12
SU1349702A3 (ru) 1987-10-30

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