US3859413A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina recovery from oil shale residue
Assignee: Oil Shale Corp
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Filing: 1972-08-09
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Granted: 1975-01-07
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Expires: 1992-08-09
Abstract
Abstract An essentially silica-free alumina product is obtained from dawsonite-bearing oil shale by a process which involves rapidly wetting and leaching the retorted residue at about 5*C to about 40*C, with a dilute alkaline leach liquor followed by precipitation of the extracted alumina directly from the leach liquor at about 60*C to about 75*C in the presence of alumina seed.
Inventors
- 👤 Frank C Haas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:32
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/06; C01F7/068
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
19 words
A PROCESS FOR RECOVERING HIGH PURITY, LOW SILICA ALUMINA FROM THE PYROLYSIS RESIDUE OF DAWSONITEBEARING OIL SHALE WHICH COMPRISES:
Claim 2
Dependent Claim
19 words
A PROCESS FOR RECOVERING HIGH PURITY, LOW SILICA ALUMINA FROM THE PYROLYSIS RESIDUE OF DAWSONITEBEARING OIL SHALE WHICH COMPRISES:
Claim 3
Dependent Claim
20 words
The process as defined in claim 1 wherein the temperature of the leach liquor is maintained at about 25* C.
Claim 4
Dependent Claim
27 words
The process as defined in claim 1 wherein the precipitation step (b) is carried out over a period of from about 30 minutes to about 4 hours.
Claim 5
Dependent Claim
25 words
The process as defined in claim 1 wherein the ratio of alumina trihydrate seed to alumina in solution varies from about 1:1 to about 8:1.
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) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |