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WO1990010735A1 - Substrat d'anode revetu d'oxycomposes de terres rares - Google Patents

Substrat d'anode revetu d'oxycomposes de terres rares Download PDF

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Publication number
WO1990010735A1
WO1990010735A1 PCT/EP1990/000364 EP9000364W WO9010735A1 WO 1990010735 A1 WO1990010735 A1 WO 1990010735A1 EP 9000364 W EP9000364 W EP 9000364W WO 9010735 A1 WO9010735 A1 WO 9010735A1
Authority
WO
WIPO (PCT)
Prior art keywords
anode
oxide
substrate
mol
surface coating
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
PCT/EP1990/000364
Other languages
English (en)
Inventor
Jean-Louis Jorda
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.)
Moltech Invent SA
Original Assignee
Moltech Invent 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
Application filed by Moltech Invent SA filed Critical Moltech Invent SA
Priority to EP90904311A priority Critical patent/EP0422142B1/fr
Priority to DE69019664T priority patent/DE69019664T2/de
Publication of WO1990010735A1 publication Critical patent/WO1990010735A1/fr
Priority to NO910306A priority patent/NO910306D0/no
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • C25C3/12—Anodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/02—Electrodes; Connections thereof
    • C25C7/025—Electrodes; Connections thereof used in cells for the electrolysis of melts

Definitions

  • the invention relates to anodes for electrowinning metals such as aluminum from molten salt electrolytes, of the type comprising a substrate made of an electroconductive oxycompound which in use is coated with a surface coating comprising at least one rare earth oxycompound, typically including cerium oxyfluoride.
  • the invention also relates to electrowinning processes using such anodes.
  • US Patent 4 614 569 describes a method of electrowinning metals by electrolysis of a melt containing a dissolved species of the metal to be won using an anode immersed in the melt wherein the anode has a metal, alloy or cermet substrate and an operative anode surface which is a protective surface coating containing a compound of a metal less noble than the metal to be electrowon, the protective coating being preserved by maintaining in the melt a suitable concentration of a species of this less noble metal.
  • the protective anode coating comprises a fluorine-containing oxycompound of cerium (referred to as "cerium oxyfluoride”) alone or in combination with additives such as compounds of tantalum, niobium, yttrium, lanthanum, praesodymium and other rare earth elements, this coating being maintained by the addition of cerium and possibly other elements to the electrolyte.
  • the electrolyte can be molten cryolite containing dissolved alumina, i.e. for the production of aluminum.
  • a promising solution to these problems has been the use of a ceramic/metal composite material of at least one ceramic phase and at least one metallic phase, comprising mixed oxides of cerium with aluminum, nickel, iron and/or copper in the form of a skeleton interwoven with a continuous metallic network of an alloy or intermetallic compound of cerium with aluminum, nickel, iron and/or copper, as described in EP-A-0 257 708.
  • these materials When used as electrode substrates, these materials have promise, particularly those based on cerium and aluminum because even if they corrode, this does not lead to corrosion products that contaminate the electrowon aluminum. Nevertheless corrosion of the substrate remains a problem.
  • US Patent 4 374 050 discloses inert electrodes for aluminum production fabricated from at least two metals or metal compounds to provide a combination metal compound.
  • an alloy of two or more metals can be surface oxidised to form an oxycompound of the metals at the surface on an unoxidised alloy substrate.
  • US Patent 4 374 761 discloses similar compositions further comprising a dispersed metal powder in compositions which may be applied as a preformed oxide composition on a metal substrate by cladding or plasma spraying. Such application techniques, however, are known to involve many drawbacks and the adhesion is particularly poor.
  • US Patent 4 620 905 describes an oxidised alloy electrode based on tin or copper with nickel, iron silver, zinc, magnesium, aluminum and yttrium, either as a cermet or partially oxidised at its surface.
  • Such partially oxidised alloys suffer serious disadvantages in that the oxide layers formed are far too porous to oxygen, and not sufficiently stable in corrosive environments.
  • the partially oxidised structures continue to oxidize and this uncontrolled oxidation causes subsequent segregation of the metal and/or oxide layer. Adherence at the ceramic-metal interfaces is particularly difficult to achieve and this very problem has hampered use of such simple composites.
  • none of these materials has proven satisfactory as substrate for cerium oxyfluoride coatings of the type discussed.
  • Improved metal-based substrates are described in European Patent Applications 88201957.3, 88201851.8, 88201852.6, 88201853.4 and 88201854.2 all as yet unpublished. These typically include a substrate made of an alloy of chromium with nickel, cobalt and/or iron. On the surface of the substrate is a chromium oxide film on top of which is a layer of copper oxide in solid solution with nickel or manganese, obtained by oxidising a layer of nickel/copper or manganese/copper which is applied eg by electroplating. It was also mentioned that the nickel oxide in the surface layer may have its electrical conductivity improved by doping with lithium.
  • Ceramic intermediate layers which in use serve as anchorage for the in-situ maintained protective coating of cerium oxyfluoride to the metal substrate, these intermediate layers including: nickel ferrite; copper oxide and nickel ferrite; doped, non-stoichiometric and partially substituted ceramic oxide spinels containing combinations of divalent nickel, cobalt, magnesium, manganese, copper and zinc with divalent/trivalent nickel, cobalt, manganese and/or iron, and optionally dopants selected from Ti 4+,
  • An object of the invention is to provide electrode substrates based on electroconductive oxycompounds which can be produced easily, have excellent conductivity and perform well as anode substrates when coated with an oxyfluoride-type coating.
  • the invention is based on the realization that sintered copper-nickel oxide suitably doped with lithium oxide to enhance conductivity fulfills the sought-after requirements of a material for the anode substrate.
  • an anode for electrowinning a metal from a molten salt electrolyte comprising an electroconductive oxycompound substrate which in use carries a surface coating comprising at least one rare earth oxycompound, is characterized in that the substrate comprises a sintered body composed of a nickel-copper-lithium oxide solid solution.
  • the nickel oxide is present in the solid solution in an amount of at least 70 mol%
  • the copper oxide is present in an amount of at most 29 mol%
  • the lithium oxide is present in an amount of at most 10mol%.
  • the solid solution contains 70-90 mol% nickel oxide, 5-29 mol% copper oxide and 1-10 mol% lithium oxide.
  • the concentration the lithium dopant preferably ranges from 1 to 10 atom % with an optimum value at about 5 atom %, this usually in combination with about 70-80 mol% nickel oxide and about 20-25 mol% copper oxide.
  • a method of preparing an anode substrate according to the invention comprises mixing powders of nickel oxide, copper oxide and a compound of lithium, firing at
  • (Ni-Cu)O solid solution can thus conveniently be prepared by mixing powders of Li(NO_), Li 2 C0 3 or LiOH; CuO; and NiO in the right proportions and firing for example at
  • the resulting sintered material shows a density of at least
  • the anode substrate according to the invention can be used as a massive body supporting the rare earth oxycompound coating. But it can, if desired, incorporate a metal or other current collector to assist the supply of electric current and facilitate connection to the power supply.
  • the rare earth oxide coating may be cerium oxyfluoride alone or preferably may be cerium oxyfluoride together with at least one compound of tatalum, niobium, yttrium, lanthanum, praesodymium and other rare earth elements.
  • the invention also provides a method of eletrowinning aluminum from molten cryolite containing alumina wherein an anode is immersed, the anode having an eletroconductive oxycompound substrate carying a surface coating comprising at least one rare earth oxycompound, the surface coating being maintained by the presence of cerium species in the molten cryolite, the method comprising passing electrolysis current between the anode and a cathode to evolve oxygen and to maintain the surface coating at the anode and to produce aluminum at the cathode.
  • a Li. 5 Ni._ 0 Cu. 2 -.O sample was prepared using powder metallurgy techniques: Li(NO.,), CuO and NiO powders were mixed in the right proportions and fired at 1000°C in air for 24 hours. The heating rate was
  • EDX analysis revealed that the concentration of nickel and copper did not significantly change during the cerium oxyfluoride deposition: 70 and 30 atom% for nickel and copper respectively for a window analysis; 76 atom% nickel and 23 atom% copper for a grain analysis.
  • This stability of the composition of the sample is an indication of the protective role of the deposit for the cryolite in the previously mentioned conditions.
  • the relative stability of the potential during the deposition may be related to the conductivity of the substrate which is strongly dependant on the lithium concentration.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Solid Thermionic Cathode (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Secondary Cells (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

Une anode d'extraction électrolytique d'un métal à partir d'un électrolyte de sel fondu comprend un substrat d'oxycomposé électroconducteur lequel lors de son utilisation porte un revêtement de surface comprenant au moins un oxycomposé de terres rares. Le substrat comprend un corps fritté composé d'une solution solide d'oxyde de nickel-cuivre-lithium, ladite solution contenant de préférence 70 à 90 mol % d'oxyde de nickel, 5 à 29 mol % d'oxyde de cuivre et 1 à 10 mol % d'oxyde de lithium.
PCT/EP1990/000364 1989-03-07 1990-03-06 Substrat d'anode revetu d'oxycomposes de terres rares Ceased WO1990010735A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP90904311A EP0422142B1 (fr) 1989-03-07 1990-03-06 Substrat d'anode revetu d'oxycomposes de terres rares
DE69019664T DE69019664T2 (de) 1989-03-07 1990-03-06 Mit einer verbindung aus seltenerdoxid beschichtetes anodensubstrat.
NO910306A NO910306D0 (no) 1989-03-07 1991-01-25 Et anodesubstrat belagt med sjeldne jordartsoxyforbindelser.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP89810175.3 1989-03-07
EP89810175 1989-03-07

Publications (1)

Publication Number Publication Date
WO1990010735A1 true WO1990010735A1 (fr) 1990-09-20

Family

ID=8203133

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1990/000364 Ceased WO1990010735A1 (fr) 1989-03-07 1990-03-06 Substrat d'anode revetu d'oxycomposes de terres rares

Country Status (8)

Country Link
EP (1) EP0422142B1 (fr)
AT (1) ATE123079T1 (fr)
AU (1) AU622000B2 (fr)
CA (1) CA2030788A1 (fr)
DE (1) DE69019664T2 (fr)
ES (1) ES2072427T3 (fr)
NO (1) NO910306D0 (fr)
WO (1) WO1990010735A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0845436A1 (fr) * 1996-11-29 1998-06-03 Sharp Kabushiki Kaisha Oxyde mixte de lithium nickel cuivre et procédé pour sa préparation et son utilisation
WO2012016511A1 (fr) * 2010-08-03 2012-02-09 江西稀有金属钨业控股集团有限公司 Procédé destiné à une lixiviation en place par injection de liquide
CN109811368A (zh) * 2019-03-20 2019-05-28 武汉大学 用于熔盐电解体系的锂离子强化型惰性阳极及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU685053B2 (en) * 1993-04-19 1998-01-15 Moltech Invent S.A. Micropyretically-produced components of aluminium production cells

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0114085A2 (fr) * 1983-01-14 1984-07-25 Eltech Systems Corporation Procédé de production électrolytique en sel fondu, anode et sa fabrication
EP0306102A1 (fr) * 1987-09-02 1989-03-08 MOLTECH Invent S.A. Electrolyse de sel fondu avec anode inconsumable

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3685760T2 (de) * 1985-02-18 1993-05-19 Moltech Invent Sa Verfahren zur herstellung von aluminium, zelle zur herstellung von aluminium und anode fuer die elektrolyse von aluminium.
EP0203884B1 (fr) * 1985-05-17 1989-12-06 MOLTECH Invent S.A. Anode de dimensions stables pour électrolyse en sel fondu et procédé d'électrolyse
JPS62284095A (ja) * 1986-06-02 1987-12-09 Permelec Electrode Ltd 耐久性を有する電解用電極及びその製造方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0114085A2 (fr) * 1983-01-14 1984-07-25 Eltech Systems Corporation Procédé de production électrolytique en sel fondu, anode et sa fabrication
EP0306102A1 (fr) * 1987-09-02 1989-03-08 MOLTECH Invent S.A. Electrolyse de sel fondu avec anode inconsumable

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0845436A1 (fr) * 1996-11-29 1998-06-03 Sharp Kabushiki Kaisha Oxyde mixte de lithium nickel cuivre et procédé pour sa préparation et son utilisation
US5955219A (en) * 1996-11-29 1999-09-21 Sharp Kabushiki Kaisha Lithium nickel copper composite oxide and its production process and use
WO2012016511A1 (fr) * 2010-08-03 2012-02-09 江西稀有金属钨业控股集团有限公司 Procédé destiné à une lixiviation en place par injection de liquide
CN109811368A (zh) * 2019-03-20 2019-05-28 武汉大学 用于熔盐电解体系的锂离子强化型惰性阳极及其制备方法
CN109811368B (zh) * 2019-03-20 2021-03-16 武汉大学 用于熔盐电解体系的锂离子强化型惰性阳极及其制备方法

Also Published As

Publication number Publication date
NO910306L (no) 1991-01-25
EP0422142B1 (fr) 1995-05-24
AU5180390A (en) 1990-10-09
ES2072427T3 (es) 1995-07-16
DE69019664D1 (de) 1995-06-29
EP0422142A1 (fr) 1991-04-17
DE69019664T2 (de) 1995-09-21
ATE123079T1 (de) 1995-06-15
AU622000B2 (en) 1992-03-26
CA2030788A1 (fr) 1990-09-08
NO910306D0 (no) 1991-01-25

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