Patent US4170533A successfully refreshed from Google Patents.
US4170533A
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Refractory article for electrolysis with a protective coating made of corundum crystals
Assignee: Rio Tinto Switzerland AG
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Filing: 1977-07-22
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Granted: 1979-10-09
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Expires: 1997-07-22
Abstract
Abstract A molten salt charge as used in the electrolysis of aluminum contains aluminum oxide in excess of the eutectic composition and is cooled at a surface colder than the melt in such a way that the aluminum oxide precipitates onto this surface in the form of corundum crystals. Such a layer of crystals provides chemical and electrical insulation to the cooling surface under the corrosive conditions produced by the charge.
Inventors
- 👤 Hanspeter Alder
- 👤 Hans Boving
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:58
CPC Classifications
C; C25; C25C; C25C3/00; C25C3/06; C23; C23D; C23D5/00; C23D5/10; C25C3/08; C25C3/085; C25C3/12; C25C3/125
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
44 words
An article of refractory material carrying a substantially continuous, compact, adherent protective coating consisting essentially of corundum crystals which are needle-like in shape and which are in part intimately grown into each other and in part held together by solidified aluminum oxide eutectic material.
Claim 2
Dependent Claim
44 words
An article of refractory material carrying a substantially continuous, compact, adherent protective coating consisting essentially of corundum crystals which are needle-like in shape and which are in part intimately grown into each other and in part held together by solidified aluminum oxide eutectic material.
Claim 3
Dependent Claim
29 words
An article according to claim 1 wherein said refractory material is a carbon pot adapted to contain an alumina-containing electrolysis melt, said pot carrying an interior coating of corundum.
Claim 4
Dependent Claim
28 words
An article according to claim 1 wherein said refractory material is an electrode frame for use in an alumina-containing electrolysis melt, said frame carrying a coating of corundum.
Claim 5
Dependent Claim
12 words
An article according to claim 1 wherein said coating is substantially uniform.
Claim 6
Dependent Claim
17 words
An article according to claim 1 wherein said refractory material is electrically insulated by said corundum coating.
Claim 7
Dependent Claim
20 words
An article according to claim 1 wherein said refractory material is poorly resistant to molten halide salts at elevated temperatures.
Claim 8
Dependent Claim
15 words
An article according to claim 1 wherein said refractory material is a poor electrical conductor.
Claim 9
Dependent Claim
17 words
An article according to claim 1 wherein the surface of said refractory material is roughened before coating.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-08 | 1983-04-09 | 1983-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-08 | 1987-04-09 | 1987-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-08 | 1991-04-09 | 1991-10-09 | $7700.00 | Window Closed / Lapsed |