Patent US3681020A successfully refreshed from Google Patents.
US3681020A
Expired / Lapsed
US
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Thermal conversion of magnesium sulfite to magnesium oxide
Assignee: Chemical Construction Corp
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Filing: 1970-06-11
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Granted: 1972-08-01
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Expires: 1990-06-11
Abstract
Abstract HYDRATED SOLID MAGNESIUM SULFITE. TYPICALLY DERIVED FROM THE SRUBBING OF A WASTE GAS STREAM WITH MAGNESIUM OXIDE-SULFITE SLURRY FOR SLUFUR DIOXIDE REMOVAL, IS CONVERTED TO SOLID MAGNESIUM OXIDE AND A SULFUR DIOXIDE-RICH GAS STREAM BY A COMBINATION OF STEPS INCLUDING DRYING TO FORM ANHYDROUS MAGNESIUM SULFITE BY HEATING THE WET HYDRATED CRYSTALS TO 300*C. TO 700*C. IN A NON-OXIDIZING ATMOSPHERE, FOLLOWED BY ADDITION OF CARBON TO THE ANHYDROUS SALT AND CALCINING OF THE MIXTURE UNDER CONTROLLED CONDITONS. THE PROCESS PRODUCES REGENERATED MAGNESIUM OXIDE AND THE SULFUR DIOXIDE-RICH GAS STREAM WITHOUT OXIDATION OF SULFITE TO SULFATE AND WITHOUT SULFUR TRIOXIDE FORMATION.
Inventors
- 👤 Indravadan S Shah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:19
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/60; C01F; C01F5/00; C01F5/02; C01F5/06; Y; Y02; Y02P; Y02P20/00; Y02P20/10; Y02P20/129
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |