EP0109358A1 - Cathode pour cellule d'électrolyse à bain fondu - Google Patents

Cathode pour cellule d'électrolyse à bain fondu Download PDF

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Publication number
EP0109358A1
EP0109358A1 EP83810496A EP83810496A EP0109358A1 EP 0109358 A1 EP0109358 A1 EP 0109358A1 EP 83810496 A EP83810496 A EP 83810496A EP 83810496 A EP83810496 A EP 83810496A EP 0109358 A1 EP0109358 A1 EP 0109358A1
Authority
EP
European Patent Office
Prior art keywords
aluminum
fragments
cathode according
melt flow
substrate
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.)
Ceased
Application number
EP83810496A
Other languages
German (de)
English (en)
Inventor
Sandor Molnar
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
Alusuisse Holdings AG
Schweizerische Aluminium AG
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
Application filed by Alusuisse Holdings AG, Schweizerische Aluminium AG filed Critical Alusuisse Holdings AG
Publication of EP0109358A1 publication Critical patent/EP0109358A1/fr
Ceased legal-status Critical Current

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Classifications

    • 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 cathode for a melt flow electrolysis cell for the production of aluminum, with wettable work surfaces which are resistant to the melt flow and which are electrically conductive.
  • the electrolysis generally takes place in a temperature range between 940 and 970 ° C. In the course of electrolysis, the electrolyte becomes poor in aluminum oxide. At a lower concentration of approx. 1 - 2% by weight. Aluminum oxide in the electrolyte leads to an anode effect, which results in a voltage increase from 4 - 4.5 V to 30 V and above, for example.
  • the generated metal flow on the surface leads to an increased chemical dissolution or to fine dispersion of the aluminum in the melt flow, which is known to result in a reduced current yield due to reoxidation.
  • both US Pat. Nos. 3,661,736 and 4,308,114 disclose a solid-state cathode for aluminum melt flow electrolysis, which consists of a composite material. Refractory grains made of a material wettable by aluminum are embedded in a carbon matrix. To produce the composite material, fine carbon powder is mixed with granular titanium diboride and treated with a suitable thermal process in the first-mentioned patent specification; granular titanium diboride is used in the second-mentioned patent specification. mixed in tar or pitch.
  • Such cathodes made of composite material are only slightly wettable by aluminum, the carbon matrix comes into contact with the melt flow. The interpolar distance can be reduced to a maximum of approximately 4 cm.
  • the inventor has set himself the task of creating a cathode for a melt flow electrolysis cell for the production of aluminum which is completely wettable by it, is not attacked by the melt flow, is inexpensive to produce and can be easily replaced.
  • the carbon, graphite, aluminum nitride and / or anthracite grains or splinters can be provided with a layer of silicon carbide, on which the actual protective layer made of aluminum-wettable material is then applied.
  • the grains or fragments forming the substrate preferably have an average linear dimension in the range between 0.2 and 10 mm.
  • the spectrum of the grain or splinter size is preferably narrow.
  • the substrate grains or chips are coated using a known method, for example sintering or melting. In this coating process, the substrate grains or chips are connected to one another and the cavities are at least partially filled with coating material. Based on the composite material, the proportion of the coating material is preferably between 2 and 40% by weight, in particular between 5 and 20% by weight. Within this proportion, layer thicknesses between 20 and 200 ⁇ m, preferably between 50 and 100 ⁇ m, are aimed for.
  • any shape can be produced with this coating process, large, shapeless pieces are preferably formed, which are then broken up into fragments with a hard object.
  • the fragments expediently have average linear dimensions between 1 and 8 cm.
  • substrate grains or fragments also burst when the large chunks are broken up.
  • the relatively soft substrate parts are removed by sandblasting or dissolved during the electrolysis process. Any directly formed moldings are of the same order of magnitude as the fragments or slightly larger.
  • the shaped pieces or fragments are poured into the tub of the electrolytic cell, the uppermost layer of the molten aluminum protruding into the electrolyte.
  • the bed is local so that the melt flow can circulate in it, albeit with greater resistance.
  • the bed is - with the working surface of the corresponding anode arranged horizontally - limited as horizontally as possible.
  • the interpolar distance is between 2 and 4 cm. The same applies to obliquely or vertically arranged work surfaces of the anodes.
  • the shaped pieces or fragments are preferably poured in such that the larger pieces are at the bottom and the smaller pieces are at the top.
  • a podium can be built below the anodes in the cathode trough that is suitable for receiving the fill.
  • Parts protruding from the podium into the molten electrolyte must consist of material that is wettable by aluminum and resistant to the electrolyte, expediently from the coating material of the substrate grains or splinters.
  • the podium has a liquid-permeable floor so that the drainage of the molten aluminum is not excessively obstructed.
  • the floor plan of a podium preferably corresponds at most to that of the corresponding anode (s).
  • the geometric change is only slight because the next coating again acts as a barrier.
  • substrate grains or fragments are preferably used, which have a size in the range of 0.5-2 mm. Even smaller substrate grains or chips offer even better protection against Damage, however, more expensive coating material that can be wetted by aluminum must be used in the production of the shaped parts or fragments.
  • the body 10 shown in FIG. 1 consists of anthracite chips 12 forming the substrate and a thin titanium diboride coating 14, which binds the substrate chips together. Before sintering together, the individual anthracite chips 12 were provided with a thin silicon carbide layer, not shown.
  • FIG. 2 Only the carbon liner 16 of the melt flow electrolysis cell for the production of aluminum is shown in FIG. 2.
  • Graphite bricks 18 are arranged on the horizontal bottom of this carbon lining, which are the foundation for the podium 20 which carries the shaped or fragments 10.
  • the higher-formed graphite bricks 18 carry the bottom plates 22 made of silicon carbide, which are provided with a specific perforation.
  • the level of the molten aluminum is always significantly above these plates 22, especially after scooping.
  • the aluminum level is lowered by h during scooping.
  • the podium is laterally delimited by plates or rods 26 protruding into the electrolyte, which can be wetted by aluminum and are not attacked by the latter or by the electrolyte 28.
  • the plates or rods 26 are supported on the outside by silicon carbide profiles 30.
  • the bulk material loosely filled into the pedestal 20 consists of shaped pieces or fragments 10 of substrate grains or fragments which are sintered together with the material which is wettable for aluminum and is inert to the melt flow. It is clearly shown that the larger shaped pieces or fragments 10 below, the smaller ones above, i.e. adjacent the anode (s) 32 are arranged.
  • the upper form or fragments 10 form an approximately horizontal plane, which has the distance d, the interpolar distance, from the working surface of the anode 32.
  • the anode 32 can be made of carbon or an incombustible material, for example oxide ceramic. Steel tub, insulation layer, cathode bar, solidified electrolyte crust and other accessories are omitted for the sake of simplicity. Like the anode (s), they are designed in a manner known to the electrolysis specialist.

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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)
EP83810496A 1982-11-15 1983-10-28 Cathode pour cellule d'électrolyse à bain fondu Ceased EP0109358A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH6635/82 1982-11-15
CH663582 1982-11-15

Publications (1)

Publication Number Publication Date
EP0109358A1 true EP0109358A1 (fr) 1984-05-23

Family

ID=4312670

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83810496A Ceased EP0109358A1 (fr) 1982-11-15 1983-10-28 Cathode pour cellule d'électrolyse à bain fondu

Country Status (3)

Country Link
US (1) US4511449A (fr)
EP (1) EP0109358A1 (fr)
AU (1) AU2096883A (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1244794A (fr) * 1983-11-29 1988-11-15 Thomas J. Hudson Cuves de reduction de l'aluminium
JPS6246964A (ja) * 1985-08-21 1987-02-28 黒崎窯業株式会社 耐食性炭化珪素複合焼結体
US4929328A (en) * 1989-03-07 1990-05-29 Martin Marietta Energy Systems, Inc. Titanium diboride ceramic fiber composites for Hall-Heroult cells
DE69325720T2 (de) * 1992-12-17 2000-04-06 Comalco Alu Elektrolysezelle für die herstellung von metallen
WO1999040239A1 (fr) * 1998-02-09 1999-08-12 Advanced Refractory Technologies, Inc. Nouveaux materiaux utilises dans la fusion electrochimique de metaux a partir de minerais
CN101949034B (zh) * 2010-09-30 2012-06-06 广西强强碳素股份有限公司 铝电解用阴极石墨化阻流块
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

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3661736A (en) * 1969-05-07 1972-05-09 Olin Mathieson Refractory hard metal composite cathode aluminum reduction cell
FR2170188A1 (en) * 1972-02-04 1973-09-14 Borax Cons Ltd Carbon cathodes for aluminium refining - with fused refractory coating to reduce erosion
GB2065174A (en) * 1979-12-05 1981-06-24 Alusuisse Cathodes for electrolytic furnaces
EP0033630A1 (fr) * 1980-01-28 1981-08-12 Diamond Shamrock Corporation Cellule électrolytique pour l'obtention d'aluminium par électrolyse de sels fondus
DE3110490A1 (de) * 1980-04-03 1981-12-24 Schweizerische Aluminium AG, 3965 Chippis Schmelzflusselektrolysezelle zur herstellung von aluminium
US4333813A (en) * 1980-03-03 1982-06-08 Reynolds Metals Company Cathodes for alumina reduction cells
US4341611A (en) * 1980-12-18 1982-07-27 Reynolds Metals Company Alumina reduction cell
FR2500488A1 (fr) * 1981-02-24 1982-08-27 Pechiney Aluminium Procede de production d'aluminium selon la technique hall-heroult et cathode en refractaire electroconducteur pour la mise en oeuvre du procede

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071420A (en) * 1975-12-31 1978-01-31 Aluminum Company Of America Electrolytic production of metal
US4097567A (en) * 1976-08-25 1978-06-27 Aluminum Company Of America Titanium diboride shapes
US4338177A (en) * 1978-09-22 1982-07-06 Metallurgical, Inc. Electrolytic cell for the production of aluminum
US4410403A (en) * 1980-06-17 1983-10-18 Aluminum Company Of America Electrolysis method
US4349427A (en) * 1980-06-23 1982-09-14 Kaiser Aluminum & Chemical Corporation Aluminum reduction cell electrode
US4308115A (en) * 1980-08-15 1981-12-29 Aluminum Company Of America Method of producing aluminum using graphite cathode coated with refractory hard metal
ZA824255B (en) * 1981-06-25 1983-05-25 Alcan Int Ltd Electrolytic reduction cells
US4439382A (en) * 1981-07-27 1984-03-27 Great Lakes Carbon Corporation Titanium diboride-graphite composites

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3661736A (en) * 1969-05-07 1972-05-09 Olin Mathieson Refractory hard metal composite cathode aluminum reduction cell
FR2170188A1 (en) * 1972-02-04 1973-09-14 Borax Cons Ltd Carbon cathodes for aluminium refining - with fused refractory coating to reduce erosion
GB2065174A (en) * 1979-12-05 1981-06-24 Alusuisse Cathodes for electrolytic furnaces
EP0033630A1 (fr) * 1980-01-28 1981-08-12 Diamond Shamrock Corporation Cellule électrolytique pour l'obtention d'aluminium par électrolyse de sels fondus
US4333813A (en) * 1980-03-03 1982-06-08 Reynolds Metals Company Cathodes for alumina reduction cells
DE3110490A1 (de) * 1980-04-03 1981-12-24 Schweizerische Aluminium AG, 3965 Chippis Schmelzflusselektrolysezelle zur herstellung von aluminium
US4341611A (en) * 1980-12-18 1982-07-27 Reynolds Metals Company Alumina reduction cell
FR2500488A1 (fr) * 1981-02-24 1982-08-27 Pechiney Aluminium Procede de production d'aluminium selon la technique hall-heroult et cathode en refractaire electroconducteur pour la mise en oeuvre du procede

Also Published As

Publication number Publication date
AU2096883A (en) 1984-05-24
US4511449A (en) 1985-04-16

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL

17P Request for examination filed

Effective date: 19841115

17Q First examination report despatched

Effective date: 19860204

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Effective date: 19870420

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Inventor name: MOLNAR, SANDOR