US3652208A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alumina extraction from alumino-silicate ores and potassium sulfate ores
Assignee: Northrop Grumman Space and Mission Systems Corp
•
Filing: 1970-05-04
•
Granted: 1972-03-28
•
Expires: 1990-05-04
Abstract
Abstract Alumino-silicate ore and a potassium sulfate bearing ore such as polyhalite or langbeinite are reacted by reducing and then calcining. Reduction decomposes the reactants and produces H2S. Calcining produces a sinter containing potassium aluminate and silicates. The aluminate is leached from the sinter with KOH and/or K2CO3 solution and then precipitated to Al(OH)3 with SO2 or CO2. Subsequent calcining yields alumina; some of the potassium carbonate or sulfite is recycled back into the system and the balance is converted to potassium salts such as potassium sulfate or potash.
Inventors
- 👤 Maksymilian Burk
- 👤 William M Bowes
- 👤 Herman C Krieg Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:45
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/16; C01B17/164; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/10; C01F7/16; C01F7/164
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
13 words
The process of claim 1 in which the alumino-silicate is a kaolin clay.
Claim 2
Dependent Claim
23 words
The process of claim 1 in which the potassium sulfate bearing ore is selected from the class consisting of polyhalite, langbeinite, and schoenite.
Claim 3
Dependent Claim
27 words
The process of claim 1 in which additional calcium for the reaction is supplied by a compound selected from the class consisting of: gypsum, anhydrite and limestone.
Claim 4
Dependent Claim
19 words
The process of claim 1 in which the reduction is carried out at a temperature of about 850*-950* C.
Claim 5
Dependent Claim
19 words
The process of claim 5 in which the reduction is carried out in an atmosphere containing water-gas and methane.
Claim 6
Dependent Claim
24 words
The process of claim 1 in which the calcination of said first batch is carried out at temperatures of about 1,000* - 1250* C.
Claim 7
Dependent Claim
20 words
The process of claim 1 in which the calcination of said first batch is carried out in an air atmosphere.
Claim 8
Dependent Claim
23 words
The process of claim 1 in which the aluminum hydroxide is precipitated with a member of the group consisting of SO2 and CO2.
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) | 1975-03-28 | 1975-09-27 | 1976-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-28 | 1979-09-27 | 1980-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-28 | 1983-09-27 | 1984-03-28 | $7700.00 | Window Closed / Lapsed |