Patent US5646941A successfully refreshed from Google Patents.
Patent US3796790A successfully refreshed from Google Patents.
US3796790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for recovering concentrated phosphoric acid
Assignee: Canadian Patents and Development Ltd
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Filing: 1972-04-25
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Granted: 1974-03-12
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Expires: 1992-04-25
Abstract
Abstract A PROCESS IS PROVIDED FOR SEPARATING PHOSPHORIC ACID (OF HIGH STRENGTH) DIRECTLY ITS SUSPENSION WITH A GELATINOUS OR A FINELY DIVIDED PRECIPITATE, SUCH AS, FOR EXAMPLE, THE CALCIUM SULFATE PRODUCT FIRST FORMED IN A PROCESS FOR PRODUCING PHOSPHORIC ACID. THE PROCESS INVOLVES TREATING THE SUSPENSION BOTH WITH A PARTICULARLY RECITED SURFACTANT AND A PARTICULARLY RECITED MINIMUM AMOUNT OF A BRIDGING LIQUID AND AGITATING UNTIL DENSE AGGLOMERATES FORM. THEN THE PHOSPHORIC ACID IS SEPARATED EASILY FROM THE AGGLOMERATES, E.G. BY DECANTING, FILTERING OR CENTRIFUGING.
Inventors
- 👤 A Sirianni
- 👤 I Puddington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:03
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/16; C01B25/18; C01B25/22
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |