EP0091914B1 - Cathode de cellule d'electrolyse de masse en fusion pour la preparation d'aluminium - Google Patents

Cathode de cellule d'electrolyse de masse en fusion pour la preparation d'aluminium Download PDF

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Publication number
EP0091914B1
EP0091914B1 EP82902974A EP82902974A EP0091914B1 EP 0091914 B1 EP0091914 B1 EP 0091914B1 EP 82902974 A EP82902974 A EP 82902974A EP 82902974 A EP82902974 A EP 82902974A EP 0091914 B1 EP0091914 B1 EP 0091914B1
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EP
European Patent Office
Prior art keywords
solid cathode
cathode
solid
aluminum
open
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
EP82902974A
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German (de)
English (en)
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EP0091914A1 (fr
Inventor
Tibor Kugler
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.)
Alcan Holdings Switzerland AG
Original Assignee
Schweizerische Aluminium AG
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Publication date
Application filed by Schweizerische Aluminium AG filed Critical Schweizerische Aluminium AG
Priority to AT82902974T priority Critical patent/ATE15079T1/de
Publication of EP0091914A1 publication Critical patent/EP0091914A1/fr
Application granted granted Critical
Publication of EP0091914B1 publication Critical patent/EP0091914B1/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 invention relates to a wettable solid-state cathode which can be used in a melt-flow electrolysis cell for the production of aluminum and comprises an aluminide of at least one transition metal of groups IV A, V A and VI A of the periodic system of the elements.
  • the electrolysis generally takes place in a temperature range of about 940 to 970 ° C.
  • the electrolyte becomes poor in aluminum oxide.
  • At a lower concentration of about 1 to 2% by weight of aluminum oxide in the electrolyte there is an anode effect, which results in a voltage increase of, for example, 4 to 4.5 V to 30 V and above.
  • the aluminum oxide concentration must be increased by adding new aluminum oxide (alumina).
  • cathodes made of titanium diboride, titanium carbide, pyrolytic graphite, boron carbide and other substances are proposed, mixtures which can be sintered together, for example, also being used.
  • the usual interpolar distance of approximately 5 cm can be reduced as far as the other parameters allow, for example circulation of the electrolyte in the interpolar gap and maintenance of the electrolysis temperature.
  • The. reduced interpolar distance causes a significant reduction in energy consumption and avoids the formation of non-uniformities in the thickness of the aluminum layer.
  • DE-OS 28 38 965 shows solid-state cathodes made of individually interchangeable elements, each with at least one power supply.
  • the interchangeable elements are made of two different materials from two mechanically rigidly interconnected parts that are resistant to thermal shock - an upper part protruding from the molten electrolyte into the separated aluminum and a lower part arranged exclusively in the liquid aluminum .
  • the upper part at least in the area of the surface, remains unchanged from aluminum-wettable material, while the lower part or its coating consists of an insulator material that is resistant to the liquid aluminum.
  • DE-OS 3045349 relates to an exchangeable wettable solid-state cathode, which consists of an aluminide from at least one metal from the group, formed from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, without a binding phase made of metallic aluminum, consists.
  • the non-aluminum components of the aluminide thus belong to group IV A, V A and / or VI A of the periodic system of the elements.
  • the chemical and thermal resistance of the aluminides allows them to be used in both molten electrolytes and molten aluminum, although they are of limited solubility in the latter. However, this solubility drops sharply as the temperature drops.
  • the solubility of a metallic non-aluminum component of the aluminide in the liquid aluminum is approximately 1%.
  • the cathode elements are therefore alloyed until the deposited liquid aluminum is saturated with one or more of the transition metals in the aluminide.
  • the elements of the aluminides alloyed during the electrolysis process are recovered from the deposited metal by cooling it to approximately 700 ° C.
  • the crystallizing aluminide can be removed from the liquid metal by known means and used again for the production of cathode elements. This creates a material cycle with relatively low losses.
  • the inventor has set himself the task of creating solid-state cathodes based on aluminides with a service life that corresponds to one or more anode service lives, with the purchase price of the cathode and the handling costs being substantially reduced.
  • the solid cathode consists essentially of a support body and an open-pore structure, at least in the region of the working surface, impregnated with aluminum saturated with transition metal / s, which structure can be fed continuously from aluminide supplies.
  • the working surface is the surface which, when the cathode is inserted in the electrolysis cell, points in the direction of the anode and through which direct electrical current flows.
  • the Alumi nium ions reduced to elemental aluminum.
  • the working surfaces of the cathodes are therefore appropriately slightly inclined so that the deposited aluminum, which forms a film on the wettable cathode, can flow off.
  • the work surfaces of the corresponding anodes which, for. B. can consist of flammable carbon or non-flammable oxide ceramics are inclined accordingly. This tendency also has an advantageous effect here: the oxygen or C0 2 formed can escape better from the molten electrolyte.
  • the open-pore structure is anchored on the support body or part of it. If this support body consists of an electrically non-conductive material, the open-pore structure impregnated with aluminum saturated with transition metal / s must reach at least liquid metal when the solid-state cathode is inserted, so that the electrical current can flow through this impregnation alloy and, if appropriate, through the structure.
  • the carrier body therefore preferably consists at least partially of a material which is electrically conductive at 900 to 1000 ° C. and is resistant to the melt flow. In this case, the current can flow mainly through the support body. Apart from the electrical conductivity, it is essential that the material of the support body is cheap and easy to form. For these reasons, carbon is particularly well suited for the supporting body.
  • the solid-state cathodes are therefore preferably designed as individually replaceable elements which stand on the cell bottom. Damaged elements can be quickly replaced.
  • the risk of damage can be significantly reduced if the solid-state cathodes are designed as elements which float in the melt flow and have lateral spaces.
  • the molten electrolyte has a density of 2.1 g / cm 3
  • the liquid aluminum has a density of 2.3 g / cm 3 .
  • the density of a floating cathode must be between these two values.
  • the density of the cathode material used is too low, appropriate pieces of iron can be used, but these must be evenly distributed and completely encased by the cathode material.
  • the weight of the iron pieces to be used is calculated so that the apparent density of the entire solid cathode is between 2.1 and 2.3 g / cm 3 .
  • the density of the cathode material used is too high, correspondingly closed cavities are formed in the cathode material.
  • Solid cathodes with the correct density float like rafts in the liquid aluminum they are preferably held at the desired distance from each other and from the cell shelf by appropriately trained spacers.
  • the open-pore structure on the one hand must be sufficiently permeable to the aluminum saturated with transition metal / s, but on the other hand it must not allow it to flow out without resistance.
  • These requirements can be formed by sintered fine-grained granules or preferably by a fiber structure in the form of a felt or a woven fabric.
  • the fibers are a few micrometers thick and are preferably made of carbon.
  • the open-pore structure impregnated with transition metal / s saturated aluminum is continuously fed from cavities arranged in the supporting body, into which the open-pore structure projects, or from another location the open-pore structure on which solid aluminide can be held.
  • the aluminum produced during the electrolysis process flows along the diagonally arranged open-pore structure, mixes with the impregnating aluminum saturated with transition metal (s) and would gradually reduce the transition metal content in it so that the open-pore structure would be attacked and gradually dissolved. This is prevented, however, by the open-pore structure being able to be fed continuously from aluminide stocks.
  • the transition metal extracted from the saturated aluminum becomes constantly replaced by new ones, so that the open-pore structure remains permanently impregnated with aluminum saturated with transition metal / s.
  • the open-pore structure in particular a 1-5 mm thick felt made of carbon fibers, is coated with a thin, well-adhering layer of titanium carbide or titanium diboride.
  • the layers that are preferably less than 0.4 ⁇ m thick are produced, for example, by CVD (Chemical Vapor Deposition). If the aluminum impregnating the felt is permanently saturated with titanium, the wettable coating is not dissolved, which can increase the life of the felt.
  • a felt consisting of coated carbon fibers has the further advantage that if the coating is faulty, the entire work surface will not become unusable, but only individual fibers will be dissolved prematurely.
  • the main advantage of the invention is thus that simple ceramic means can be used to replace expensive ceramic moldings by supporting bodies made of a cheap, easily moldable material with an open-pore surface structure impregnated with aluminum saturated with transition metal / s.
  • the solid-state cathodes according to the invention are also particularly suitable for converting existing aluminum melt flow electrolysis cells.
  • solid cathodes 10 and anode blocks 12 arranged in pairs form the electrode units of the electrolytic cell.
  • the solid-state cathode 10 consists of a shaped support body 14 made of carbon and a felt 16 made of carbon fibers coated with titanium carbide and fastened on the working surface facing the anode body 12. Rags of this approximately 4 mm thick felt 16 extend into a cavity 18 in the carrier body 14, which is filled with a titanium aluminide 19 which is dough at electrolysis temperature and which consists, for example, of 80% by weight aluminum and 20% by weight titanium.
  • the feet 20 of the support body 14 stand in correspondingly shaped recesses in the carbon base 22 of the electrolytic cell.
  • the density of the solid-state cathode 10 must therefore be greater than that of the liquid aluminum 24.
  • the felt 16 is impregnated with aluminum saturated with titanium, which system forms the cathode.
  • the deposited aluminum mixes with the titanium-saturated aluminum in the felt and flows to the center of the electrode element, depending on the inclination of the working surface of the solid-state cathode.
  • the felt 16 acts like a wick in the oil, liquid alloy is drawn from the cavity 18 with the pasty titanium aluminide, thus replacing the current losses. Without this replacement of the spent titanium, the deposited aluminum would dissolve the titanium carbide coating on the carbon fibers and render the cathode surface non-wettable.
  • a solid-state cathode 10 and an anode block 12 form a pair of electrodes.
  • the support body 14 consists of an insulating material, for example of highly sintered aluminum oxide, aluminum oxide-containing ceramics, silicon carbide or silicon nitride-bonded silicon carbide.
  • the felt 16 In order to ensure that the electrical direct current flows away, the felt 16 always extends along as far as possible all side surfaces of the support body 14 into the liquid aluminum 24.
  • the cavity 18 is trough-shaped, with a relatively large opening, and is filled with solid titanium aluminide granules which consist, for example, of 55% by weight of aluminum and 45% by weight of titanium.
  • the felt 16 does not reach down into the cavity 18;
  • the aluminum impregnating the felt 16 with titanium is saturated by the convection of the molten electrolyte 26.
  • the deposited aluminum flows through an opening 28 in the support body 14.
  • the apparent density of the entire solid cathode, at working temperature, must be between the density of the molten electrolyte and the molten aluminum. In the case of supporting bodies 14 made of carbon, this is achieved by inserting iron pieces 30 into closed cavities, for example in the form of a ring.
  • solid cathodes 10 attached to a cathodic suspension system 36 and anode bodies 12 attached to an anodic suspension system 38 are alternatively arranged.
  • the felt 16 is fed by means of a sleeve 34 which is placed over the support rods of the support body 14 and which is made of a solid aluminum minid exist.
  • the cathodes and anodes can be shifted to the right in the direction of the arrow.
  • a mechanism known per se ensures that the same interpolar distances exist between the anode and cathode after each shift.
  • anodes 12 or cathodes 14 arranged on the left have to be displaced more than those arranged on the right.
  • Burned-off anodes, along with the cathode, are removed on the right. A sufficiently large space has now been created on the left side so that the cathode can be reinserted together with a new anode.

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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)

Claims (10)

1. Cathode à corps solide, mouillable, utilisable dans une cellule d'électrolyse de la masse en fusion pour la fabrication de l'aluminium et contenant un aluminure d'au moins un métal de transition des groupes IV A, VA et VI A de la classification périodique des éléments, caractérisée en ce que la cathode à corps solide (10) est essentiellement constituée d'un corps support (14) et d'une structure (16) à pores ouverts, située dans la zone de la surface de travail, imprégnée d'aluminium saturé en métal/métaux de transition et que l'on peut alimenter de façon continue à partir de réserves d'aluminure (19,34).
2. Cathode à corps solide selon la revendication 1, caractérisée en ce que la cathode à corps solide (10) est conçue sous forme d'un élément échangeable.
3. Cathode à corps solide selon la revendication 1 ou la revendication 2, caractérisée en ce que son corps support (14) est au moins partiellement constitué d'un matériau électriquement bon conducteur entre 900 et 1000°C et stable à l'égard du bain de fusion, de préférence de carbone.
4. Cathode à corps solide selon au moins l'une des revendications 1 à 3, caractérisée en ce que le corps support (14) comporte au moins, pour recevoir l'aluminure, un volume creux (8) dans lequel la structure (16) à pores ouverts pénètre de préférence.
5. Cathode à corps solide selon au moins l'une des revendications 1 à 4, caractérisée en ce que la structure (16) à pores ouverts est constituée de grenailles à grain fin agglomérés par frittage.
6. Cathode à corps solide selon au moins l'une des revendications 1 à 4, caractérisée en ce que la structure (16) à pores ouverts est constituée de fibres, de préférence d'un feutre ou d'un tissu.
7. Cathode à corps solide selon la revendication 6, caractérisée en ce que la structure (16) à pores ouverts est constituée d'un feutre de fibres de carbone, de préférence d'une épaisseur de 1-5 mm.
8. Cathode à corps solide selon au moins l'une des revendications 1 à 7, caractérisée en ce que, dans le cas de l'utilisation de l'aluminure de titane, la structure (16) à pores ouverts est revêtue de carbure de titane ou de diborure de titane, de préférence une épaisseur de 0,4 um.
9. Cathode à corps solide selon au moins l'une des revendications 1 à 8, caractérisée en ce que la cathode à corps solide (10) présente, entre 900 et 1000°C, une densité apparente qui se situe entre celles de l'électrolyte et de l'aluminium liquide, de préférence entre 2,1 et 2,3 g/cm3 et en ce qu'elle comporte des écarteurs (32).
10. Cathode à corps solide selon la revendication 9, caractérisée en ce que pour atteindre la densité apparente correcte, on utilise des morceaux de fer (30) régulièrement répartis et enveloppés dans le matériau de la cathode.
EP82902974A 1981-10-23 1982-10-14 Cathode de cellule d'electrolyse de masse en fusion pour la preparation d'aluminium Expired EP0091914B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82902974T ATE15079T1 (de) 1981-10-23 1982-10-14 Kathode fuer eine schmelzflusselektrolysezelle zur herstellung von aluminium.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH6788/81 1981-10-23
CH6788/81A CH648870A5 (de) 1981-10-23 1981-10-23 Kathode fuer eine schmelzflusselektrolysezelle zur herstellung von aluminium.

Publications (2)

Publication Number Publication Date
EP0091914A1 EP0091914A1 (fr) 1983-10-26
EP0091914B1 true EP0091914B1 (fr) 1985-08-21

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ID=4315036

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82902974A Expired EP0091914B1 (fr) 1981-10-23 1982-10-14 Cathode de cellule d'electrolyse de masse en fusion pour la preparation d'aluminium

Country Status (8)

Country Link
US (1) US4462886A (fr)
EP (1) EP0091914B1 (fr)
CA (1) CA1209526A (fr)
CH (1) CH648870A5 (fr)
DE (1) DE3142686C1 (fr)
IT (1) IT1152748B (fr)
NO (1) NO832198L (fr)
WO (1) WO1983001465A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102953083A (zh) * 2011-08-25 2013-03-06 贵阳铝镁设计研究院有限公司 内腔阴极结构铝电解槽

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2518124A1 (fr) * 1981-12-11 1983-06-17 Pechiney Aluminium Elements cathodiques flottants, a base de refractaire electroconducteur, pour la production d'aluminium par electrolyse
US4544457A (en) * 1982-05-10 1985-10-01 Eltech Systems Corporation Dimensionally stable drained aluminum electrowinning cathode method and apparatus
DE3375409D1 (en) * 1982-05-10 1988-02-25 Eltech Systems Corp Aluminum wettable materials
EP0096001B1 (fr) * 1982-05-10 1987-01-14 Eltech Systems Corporation Cathode dimensionellement stable à drainage pour l'obtention électrolytique d'aluminium, méthode et appareil pour sa fabrication
US4560448A (en) * 1982-05-10 1985-12-24 Eltech Systems Corporation Aluminum wettable materials for aluminum production
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.
US4622111A (en) * 1983-04-26 1986-11-11 Aluminum Company Of America Apparatus and method for electrolysis and inclined electrodes
US4664760A (en) * 1983-04-26 1987-05-12 Aluminum Company Of America Electrolytic cell and method of electrolysis using supported electrodes
US4596637A (en) * 1983-04-26 1986-06-24 Aluminum Company Of America Apparatus and method for electrolysis and float
WO1992003597A1 (fr) * 1990-08-20 1992-03-05 Comalco Aluminium Limited Cellules de fusion d'aluminium ameliorees
DE4118304A1 (de) * 1991-06-04 1992-12-24 Vaw Ver Aluminium Werke Ag Elektrolysezelle zur aluminiumgewinnung
CA2108072A1 (fr) * 1992-03-19 1995-04-09 Robert P. Coe Protection des billets de spectacle contre la contrefacon
AU688098B2 (en) * 1994-09-08 1998-03-05 Moltech Invent S.A. Aluminium electrowinning cell with improved carbon cathode blocks
US5472578A (en) * 1994-09-16 1995-12-05 Moltech Invent S.A. Aluminium production cell and assembly
US5498320A (en) * 1994-12-15 1996-03-12 Solv-Ex Corporation Method and apparatus for electrolytic reduction of fine-particle alumina with porous-cathode cells
AU779737B2 (en) * 1999-10-26 2005-02-10 Moltech Invent S.A. Drained-cathode aluminium electrowinning cell with improved electrolyte circulation
EP1366216B1 (fr) * 2001-03-07 2004-08-04 MOLTECH Invent S.A. Cellule pour l'electro-obtention d'aluminium fonctionnant avec des anodes a base metallique
CN101698945B (zh) * 2009-11-03 2011-07-27 中国铝业股份有限公司 一种碳素纤维增强型阴极炭块及其制备方法

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BE549859A (fr) * 1955-07-28
US3459515A (en) * 1964-03-31 1969-08-05 Du Pont Cermets of aluminum with titanium carbide and titanium and zirconium borides
US3471380A (en) * 1966-10-25 1969-10-07 Reynolds Metals Co Method of treating cathode surfaces in alumina reduction cells
US3661736A (en) * 1969-05-07 1972-05-09 Olin Mathieson Refractory hard metal composite cathode aluminum reduction cell
US4224128A (en) * 1979-08-17 1980-09-23 Ppg Industries, Inc. Cathode assembly for electrolytic aluminum reduction cell
US4339316A (en) * 1980-09-22 1982-07-13 Aluminum Company Of America Intermediate layer for seating RHM tubes in cathode blocks

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102953083A (zh) * 2011-08-25 2013-03-06 贵阳铝镁设计研究院有限公司 内腔阴极结构铝电解槽
CN102953083B (zh) * 2011-08-25 2016-08-24 贵阳铝镁设计研究院有限公司 内腔阴极结构铝电解槽

Also Published As

Publication number Publication date
US4462886A (en) 1984-07-31
EP0091914A1 (fr) 1983-10-26
NO832198L (no) 1983-06-17
IT1152748B (it) 1987-01-07
DE3142686C1 (de) 1983-02-03
CA1209526A (fr) 1986-08-12
CH648870A5 (de) 1985-04-15
WO1983001465A1 (fr) 1983-04-28
IT8223834A0 (it) 1982-10-20

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