US3583909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of phosphate ion by flotation with an anionic surfactant
Assignee: WR Grace and Co
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Filing: 1970-02-05
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Granted: 1971-06-08
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Expires: 1990-02-05
Abstract
Abstract PHOSPHATE IONS IN WASTE WATERS CAN BE REMOVED FROM THE WATER BY FIRST ADDING AN ION WHICH, WHEN ADDED IN SUFFICIENT AMOUNTS, WOULD FORM AN INSOLUBLE PHOSPHATE PRECIPITATE, BUT HERE, BEING ADDED IN RELATIVELY SMALL AMOUNTS, DOES NOT PER SE FORM SUCH PRECIPITATE; THEN ADDING AN ANIONIC SURFACTANT TO FORM A PHOSPHATE-CONTAINING PRECIPITATE, AND FLOATING SAID PRECIPITATE TO THE SURFACE WITH BUBBLES. THE PRECIPITATE WHICH HAS BEEN FLOATED TO THE SURFACE CAN THEN BE REMOVED IN THE RESULTANT FROTH, LEAVING THE REMAINDER OF THE SOLUTION RELATIVELY FREE OF PHOSPHATE IONS.
Inventors
- 👤 Jacob Block
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:22
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/02; B03D1/021; B03D1/14; B03D1/24; B03D1/26; C; C02; C02F; C02F1/00; C02F1/24; B03D1/1443; B03D1/1462; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/906
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |