US3087790A
Expired / Lapsed
US
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Reductive decomposition of calcium sulfate
Assignee: IOWA STATE COLLEGE RES FOUND
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Filing: 1959-09-04
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Granted: 1963-04-30
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Expires: 1979-09-04
Abstract
No abstract record available.
Inventors
- 👤 Thomas D Wheelock
- 👤 David R Boylan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:12
CPC Classifications
C; C01; C01F; C01F11/00; C01F11/02; C01F11/08; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/501; C01B17/506
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
63 words
IN THE GASEOUS REDUCTION OF CALCIUM SULFATE TO PROVIDE CALCIUM OXIDE SUBSTANTIALLY FREE OF CALCIUM SULFIDE, THE STEP OF CONTACTING AT A TEMPERATURE IN THE RANGE OF 2150-2250*F. SAID CALCIUM SULFATE WITH A GASEOUS MIXTURE COMPRISING A REDUCING GAS, CO2, AND AN INERT GAS, SAID CONTACTING BEING CARRIED OUT IN THE PRESENCE OF SO2, SAID REDUCING GAS CONSTITUTING ABOUT 1-7% OF SAID MIX-
Claim 2
Dependent Claim
63 words
IN THE GASEOUS REDUCTION OF CALCIUM SULFATE TO PROVIDE CALCIUM OXIDE SUBSTANTIALLY FREE OF CALCIUM SULFIDE, THE STEP OF CONTACTING AT A TEMPERATURE IN THE RANGE OF 2150-2250*F. SAID CALCIUM SULFATE WITH A GASEOUS MIXTURE COMPRISING A REDUCING GAS, CO2, AND AN INERT GAS, SAID CONTACTING BEING CARRIED OUT IN THE PRESENCE OF SO2, SAID REDUCING GAS CONSTITUTING ABOUT 1-7% OF SAID MIX-
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) | 1966-04-29 | 1966-10-29 | 1967-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-04-29 | 1970-10-29 | 1971-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-04-29 | 1974-10-29 | 1975-04-30 | $7700.00 | Window Closed / Lapsed |