US4614569A
Expired / Lapsed
US
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Molten salt electrowinning method, anode and manufacture thereof
Assignee: Moltech Invent SA
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Filing: 1984-01-13
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Granted: 1986-09-30
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Expires: 2004-01-13
Abstract
Abstract A method of electrowinning a metal such as aluminum from e.g. a cryolite based melt containing alumina employs an enode having as its operative surface a protective coating which is maintained by the presence of constituents of the coating dissolved in the melt. The protective coating is preferably a fluorine-containing cerium oxycompound electro-deposited in-situ from cerium species dissolved in a fluoride-based melt.
Inventors
- 👤 Jean J. Duruz
- 👤 Jean-Pierre Derivaz
- 👤 Pierre-Etienne Debely
- 👤 Iudita L. Adorian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:26
CPC Classifications
C; C25; C25C; C25C7/00; C25C7/02; C25C7/025; C25C3/00; C25C3/06; C25C3/08; C25C3/12
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
95 words
A method of electrowinning a metal by the electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the operative anode surface has a complex, inorganic protective coating containing metal in non-elemental form, with the metal of the complex being other than the metal to be won, which complex protective coating is maintained by the presence of constituents of the coating dissolved in the melt including the metal of the complex at a concentration well below its solubility limit in the melt.
Claim 2
Independent Claim
95 words
A method of electrowinning a metal by the electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the operative anode surface has a complex, inorganic protective coating containing metal in non-elemental form, with the metal of the complex being other than the metal to be won, which complex protective coating is maintained by the presence of constituents of the coating dissolved in the melt including the metal of the complex at a concentration well below its solubility limit in the melt.
Claim 3
Independent Claim
23 words
The method of clam 1, wherein cerium is dissolved in a fluoride-containing melt and the protective coating is predominantly a fluorine-containing cerium oxycompound.
Claim 4
Independent Claim
23 words
The method of clam 1, wherein cerium is dissolved in a fluoride-containing melt and the protective coating is predominantly a fluorine-containing cerium oxycompound.
Claim 5
Dependent Claim
15 words
The method of claim 2, wherein the protective coating consists essentially of fluorine-containing ceric oxide.
Claim 6
Dependent Claim
26 words
The method of claim 2 or 3, wherein at least one fluoride, oxide, oxyfluoride, sulfide, oxysulfide or hydride of the cerium is dissolved in the melt.
Claim 7
Dependent Claim
13 words
The method of claim 3, wherein the protective coating is electro-deposited in situ.
Claim 8
Dependent Claim
34 words
The method of claim 3, wherein an anode substrate containing or precoated with cerium as metal, alloy or intermetallic compound with at least one other metal, or as compound is immersed in the melt.
Claim 9
Independent Claim
53 words
A method of electrowinning a metal by the electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the anode has as its operative surface an anodically active and electronically conductive coating of at least one fluorine-containing oxycompound of cerium.
Claim 10
Independent Claim
53 words
A method of electrowinning a metal by the electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the anode has as its operative surface an anodically active and electronically conductive coating of at least one fluorine-containing oxycompound of cerium.
Claim 11
Dependent Claim
16 words
The method of claim 7 for the electrowinning of aluminium from a cryolite-based melt containing alumina.
Claim 12
Dependent Claim
26 words
A molten salt electrolysis anode comprising an electrically conductive body having an anodically active and electronically conductive surface of at least one fluorine-containing oxycompound of cerium.
Claim 13
Dependent Claim
26 words
A molten salt electrolysis anode comprising an electrically conductive body having an anodically active and electronically conductive surface of at least one fluorine-containing oxycompound of cerium.
Claim 14
Dependent Claim
14 words
The anode of claim 9, wherein the surface is composed of an electrodeposited coating.
Claim 15
Dependent Claim
19 words
The anode of claim 10, wherein the coating is a dense electrodeposited coating consisting essentially of fluorine-containing ceric oxide.
Claim 16
Dependent Claim
25 words
The anode of claim 9, 10 or 11, wherein the anode body is composed of a conductive ceramic, cermet, metal, alloy, intermetallic compound and/or carbon.
Claim 17
Dependent Claim
26 words
The anode of claim 12, wherein the anode body is a carbon substrate coated with a layer of conductive ceramic, cermet, metal, alloy or intermetallic compound.
Claim 18
Dependent Claim
18 words
The anode of claim 9, wherein the anode body includes cerium, compounds thereof, or mixtures of the foregoing.
Claim 19
Dependent Claim
22 words
The anode of claim 9, wherein the coating consists of at least one fluorine-containing cerium oxycompound and at least one other material.
Claim 20
Dependent Claim
28 words
The anode of claim 15 wherein said other material is selected from the group consisting of electrolyte for said molten salt electrolysis, NaF, complex fluoro-compounds and mixtures thereof.
Claim 21
Dependent Claim
23 words
The anode of claim 16, wherein said complex fluoro-compounds are NaCeF 4 , Na 7 Ce 6 F 31 , and their mixtures.
Claim 22
Dependent Claim
34 words
A method of producing the anode body of claim 9, comprising inserting the anode body in a fluoride containing molten salt electrolyte containing cerium and passing current to electrodeposit a fluorine-containing oxycompound of cerium.
Claim 23
Dependent Claim
16 words
The method of claim 18, wherein the molten salt electrolyte is a cryolite-based melt containing alumina.
Claim 24
Dependent Claim
16 words
The method of claim 19, which is carried out in situ in an aluminum production cell.
Claim 25
Dependent Claim
32 words
A method of producing the anode of claim 9, wherein a coating of the fluorine-containing cerium oxycompound is applied to the anode body prior to inserting the anode into a molten electrolyte.
Claim 26
Dependent Claim
13 words
The anode of claim 9 wherein said fluorine-containing oxycompound of cerium contains CeOF.
Claim 27
Dependent Claim
35 words
The anode of claim 9 wherein said surface has a major phase of cerium oxide/fluoride composition in atomic proportion corresponding at least substantially to the formula Ce 51 .3 O 39 .5 F 9 .2.
Claim 28
Dependent Claim
35 words
An anode especially adapted for molten salt electrolysis, said anode comprising an anodically active and electronically conductive surface of at least one fluorine-containing oxycompound of a metal in mixture with at least one complex fluoro-compound.
Claim 29
Dependent Claim
35 words
An anode especially adapted for molten salt electrolysis, said anode comprising an anodically active and electronically conductive surface of at least one fluorine-containing oxycompound of a metal in mixture with at least one complex fluoro-compound.
Claim 30
Dependent Claim
19 words
The anode of claim 24 wherein the metal of said fluorine-containing oxycompound is also present in said complex fluoro-compound.
Claim 31
Dependent Claim
10 words
The anode of claim 25 wherein said metal is cerium.
Claim 32
Dependent Claim
20 words
The anode of claim 24 wherein said fluorine-containing oxycompound includes CeOF and said complex fluoro-compound contains cerium plus alkali metal.
Claim 33
Dependent Claim
22 words
The anode of claim 24 wherein said complex fluoro-compound includes NaCeF 4 , Na 7 Ce 6 F 31 and their mixtures.
Claim 34
Dependent Claim
13 words
The anode of claim 24 wherein said surface also includes alkali metal fluoride.
Claim 35
Independent Claim
64 words
The method of electrowinning a metal more noble than cerium by electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the operative anode surface has a complex inorganic protective coating containing cerium in non-elemental form, which is maintained by the presence of constituents of the coating dissolved in the melt.
Claim 36
Independent Claim
64 words
The method of electrowinning a metal more noble than cerium by electrolysis of a melt containing dissolved species of the metal to be won using an anode immersed in the melt, characterized in that the operative anode surface has a complex inorganic protective coating containing cerium in non-elemental form, which is maintained by the presence of constituents of the coating dissolved in the melt.
Claim 37
Dependent Claim
23 words
The method of claim 30 wherein cerium is dissolved in the melt at a concentration well below its solubility limit in said melt.
Claim 38
Dependent Claim
43 words
The method of claim 30 wherein said metal to be won is selected from the group consisting of Group Ia, Group IIa, Group IIIa, Group IVb, Group Vb, and Group VIIb metals, as well as from their mixtures where such exist for electrowinning.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1989-09-29 | 1990-03-31 | 1990-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-29 | 1994-03-31 | 1994-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-29 | 1998-03-31 | 1998-09-30 | $7700.00 | Window Closed / Lapsed |