US4039401A
Expired / Lapsed
US
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Aluminum production method with electrodes for aluminum reduction cells
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1976-02-13
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Granted: 1977-08-02
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Expires: 1996-02-13
Abstract
Abstract An electrode for aluminum reduction cells wherein an electrode base at least in its portion that is brought into contact with a molten salt bath is coated with a composition comprising at least 50% by weight of electronic conductive oxide ceramics, or said portion of the electrode is made of said composition.
Inventors
- 👤 Koichi Yamada
- 👤 Tadanori Hashimoto
- 👤 Kazuo Horinouchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:35
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C25C3/08; C25C3/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
254 words
A method for producing aluminum by molten salt electrolysis of aluminum oxide which comprises electrolyzing aluminum oxide dissolved in a molten salt containing aluminum sodium fluoride as the main component by passing a direct current through an anode to a cathode disposed in said molten salt, wherein at least a portion of said anode and said cathode that is brought into contact with said molten salt is made or covered with a composition containing at least about 50% by weight of electronic conductive oxide ceramics having chemical resistance to the molten salt, said oxide ceramics being selected from spinel structure oxides having the general formula XYY'O 4 (wherein X is a divalent or tetravalent metal, Y and Y' may be either the same or different and are trivalent or divalent metals, O is oxygen atom, provided that when X is a divalent metal, Y and Y' are selected from trivalent metals but the spinel structure oxides are excluded in which both Y and Y' are trivalent iron, Fe(III), and when X is tetravalent metal, Y and Y' are selected from divalent metals), perovskite structure oxides having the general formula RMO 3 (wherein R is a monovalent, divalent or trivalent metal, M is a pentavalent, tetravalent or trivalent metal, O is oxygen atom, provided that when R is a monovalent metal, M is selected from pentavalent metals, when R is divalent metal, M is selected from tetravalent metals, and when R is a trivalent metal, M is selected from trivalent metals), or a mixture thereof.
Claim 2
Independent Claim
254 words
A method for producing aluminum by molten salt electrolysis of aluminum oxide which comprises electrolyzing aluminum oxide dissolved in a molten salt containing aluminum sodium fluoride as the main component by passing a direct current through an anode to a cathode disposed in said molten salt, wherein at least a portion of said anode and said cathode that is brought into contact with said molten salt is made or covered with a composition containing at least about 50% by weight of electronic conductive oxide ceramics having chemical resistance to the molten salt, said oxide ceramics being selected from spinel structure oxides having the general formula XYY'O 4 (wherein X is a divalent or tetravalent metal, Y and Y' may be either the same or different and are trivalent or divalent metals, O is oxygen atom, provided that when X is a divalent metal, Y and Y' are selected from trivalent metals but the spinel structure oxides are excluded in which both Y and Y' are trivalent iron, Fe(III), and when X is tetravalent metal, Y and Y' are selected from divalent metals), perovskite structure oxides having the general formula RMO 3 (wherein R is a monovalent, divalent or trivalent metal, M is a pentavalent, tetravalent or trivalent metal, O is oxygen atom, provided that when R is a monovalent metal, M is selected from pentavalent metals, when R is divalent metal, M is selected from tetravalent metals, and when R is a trivalent metal, M is selected from trivalent metals), or a mixture thereof.
Claim 3
Dependent Claim
42 words
A method according to claim 1 wherein the electrode is coated with a composition containing at least about 50% by weight of said electronic conductive oxide ceramics at least in its portion that is brought into contact with the molten salt bath.
Claim 4
Dependent Claim
40 words
A method according to claim 1 wherein the electrode is made of a composition containing at least about 50% by weight of said electronic conductive oxide ceramics at least its portion that is brought into contact with molten salt bath.
Claim 5
Dependent Claim
26 words
A method according to claim 1 wherein said electrode is formed of a composition containing at least 70% by weight of said electronic conductive oxide ceramics.
Claim 6
Dependent Claim
29 words
A method according to claim 1 wherein the electrical conductivity of said electronic conductive oxide ceramics is at least 0.1 Ω - 1 cm - 1 (at 1000° C.).
Claim 7
Dependent Claim
21 words
A method according to claim 1 wherein the melting point of said electronic conductive oxide ceramics is at least 1200° C.
Claim 8
Dependent Claim
57 words
A method according to claim 1 wherein said electronic conductive oxide ceramics is selected from spinel structure oxides including CoCr 2 O 4 , TiFe 2 O 4 , CoY 2 O 4 , NiCr 2 O 4 and NiCo 2 O 4 , perovskite structure oxides including LaCrO 3 and LaNiO 3 and a mixture thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-01 | 1981-01-31 | 1981-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-01 | 1985-01-31 | 1985-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-01 | 1989-01-31 | 1989-08-02 | $7700.00 | Window Closed / Lapsed |