US4355017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aluminum electrolytic cell cathode waste recovery
Assignee: Rio Tinto Aluminium Ltd
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Filing: 1981-05-14
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Granted: 1982-10-19
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Expires: 2001-05-14
Abstract
Abstract Recovery of fluoride values from carbonaceous waste cathode materials is achieved by reacting the waste materials with oxygen, water, and sulfur dioxide at temperatures between about 600 DEG C. and 1200 DEG C.
Inventors
- 👤 Bernard W. Gamson
- 👤 Howard W. Hayden, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:48
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/19; C01B7/191; C25; C25C; C25C3/00; C25C3/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
43 words
A process for the decomposition of carbon cathode waste material containing cryolite, aluminum fluoride, calcium fluoride, and sodium fluoride which comprises heating the waste material in the presence of water, oxygen, and sulfur dioxide to a temperature at which hydrogen fluoride is generated.
Claim 2
Dependent Claim
43 words
A process for the decomposition of carbon cathode waste material containing cryolite, aluminum fluoride, calcium fluoride, and sodium fluoride which comprises heating the waste material in the presence of water, oxygen, and sulfur dioxide to a temperature at which hydrogen fluoride is generated.
Claim 3
Dependent Claim
24 words
A process as set forth in claim 1, wherein said temperature is within the range of from about 770° C. to about 884° C.
Claim 4
Dependent Claim
32 words
A process as set forth in claim 1, wherein said decomposition takes place in a reactor selected from the group consisting of fluidized bed reactors, packed bed reactors, and closed furnace reactors.
Claim 5
Dependent Claim
16 words
A process as set forth in claim 1, wherein said sulfur dioxide is formed in situ.
Claim 6
Dependent Claim
24 words
A process as set forth in claims 2, 3, or 4, wherein said hydrogen fluoride is reacted with aluminum trihydrate to form aluminum trifluoride.
Claim 7
Dependent Claim
23 words
A process as set forth in claims 2, 3, or 4, wherein said hydrogen fluoride is reacted with sodium aluminate to form cryolite.
Claim 8
Dependent Claim
24 words
A process as set forth in claims 2, 3, or 4, wherein said hydrogen fluoride is utilized for the production of a fluorinated hydrocarbon.
Claim 9
Dependent Claim
26 words
A process as set forth in claims 3 or 4, wherein said temperature is within the range of from about 770° C. to about 884° C.
Claim 10
Dependent Claim
26 words
A process as set forth in claims 3 or 4, wherein said temperature is within the range of from about 850° C. to about 880° C.
Claim 11
Dependent Claim
21 words
A process as set forth in claims 2, 3, or 4 wherein said decomposition is conducted in a fluidized bed reactor.
Claim 12
Dependent Claim
22 words
A process as set forth in claims 2, 3, or 4, wherein said decomposition is conducted in a multiple-stage fluidized bed reactor.
Claim 13
Dependent Claim
28 words
A process as set forth in claims 2, 3, or 4 wherein said waste materials are particles ranging in size from about 1 mm to about 5 mm.
Claim 14
Dependent Claim
27 words
A process as set forth in claims 3 or 4 wherein said heating is within the temperature range of from about 600° C. to about 1200° C.
Claim 15
Dependent Claim
27 words
A process as set forth in claims 2, 3, or 4, wherein said sulfur dioxide is produced by the addition of sulfur to the heated carbonaceous materials.
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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) | 1985-10-18 | 1986-04-19 | 1986-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-10-18 | 1990-04-19 | 1990-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-10-18 | 1994-04-19 | 1994-10-19 | $7700.00 | Window Closed / Lapsed |