Patent US3969492A successfully refreshed from Google Patents.
US3969492A
Expired / Lapsed
US
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Recovery of elemental sulfur from sulfur dioxide bearing waste gases
Assignee: Siemens Water Technologies Holding Corp
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Filing: 1973-10-29
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Granted: 1976-07-13
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Expires: 1993-10-29
Abstract
Abstract Process for effecting the selective removal of sulfur dioxide values from industrial waste gases or the like and conversion thereof to elemental sulfur wherein a particularly constituted solution of mixed ammonium phosphates is exposed to absorbent contact with the sulfur dioxide bearing gas stream followed by recovery of the sulfur values therefrom and regeneration of the absorbent solution preparatory to reexposure thereof to the sulfur dioxide bearing gas stream.
Inventors
- 👤 Michael Witte
- 👤 Manankumar S. Mehta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:30
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/02; C01B17/04; C01B17/05
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
98 words
In the removal of sulfur dioxide values from a sulfur dioxide bearing industrial gas stream, the steps of introducing a sulfur dioxide bearing gas stream, into absorbent contact with an aqueous solution of mixed mono-ammonium phosphate and di-ammonium phosphate in which the weight proportion of mono- to di-ammonium phosphate is in the range of about 4 to 1 to about 10 to 1 to effect removal of sulfur dioxide values from said gas stream in said solution, and reacting said absorbed sulfur dioxide values in said solution with hydrogen sulfide to reduce the sulfur therein to elemental sulfur.
Claim 2
Dependent Claim
98 words
In the removal of sulfur dioxide values from a sulfur dioxide bearing industrial gas stream, the steps of introducing a sulfur dioxide bearing gas stream, into absorbent contact with an aqueous solution of mixed mono-ammonium phosphate and di-ammonium phosphate in which the weight proportion of mono- to di-ammonium phosphate is in the range of about 4 to 1 to about 10 to 1 to effect removal of sulfur dioxide values from said gas stream in said solution, and reacting said absorbed sulfur dioxide values in said solution with hydrogen sulfide to reduce the sulfur therein to elemental sulfur.
References Cited (Backward Citations)
US2142987A
Cited
GB599073A
Cited
US3431072A
Cited
GB1240753A
Cited
US3633339A
Cited
US3630672A
Cited
US3767777A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |