US3740331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for precipitation of heavy metal sulfides
Assignee: Sybron Transition Corp
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Filing: 1971-06-23
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Granted: 1973-06-19
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Expires: 1991-06-23
Abstract
Abstract HEAVY METAL POLLUTANT IONS ARE REMOVED FROM AN AQUEOUS SOLUTION IN ASULFIDE PRECIPITATION PROCESS THAT AVOIDS GENERATION OF NOXIOUS AMOUNTS OF HYDROGEN SULFIDE AND THE FORATION OF SOLUBLE COMPLEXES OF SULFIDE IONS. SULFIDE ION AND A HEAVY METAL ION THAT FORMS A SULFIDE HAVING A HIGHER EQUILIBRIUM SULFIDE ION CONCENTRATION THAN THE SULFIELD OF THE HEAVY METAL POLLUTANT ARE ADDED TO THE SOLUTION. THE ADDED HEAVY METAL ACTS AS A SCAVENGER FOR EXCESS SULFIDE. IN SOME CASES THE ADDED HEAVY METAL AND THE HEAVY METAL POLLUTANT FORM CO-PRECIPITATES WHICH RESULT IN MORE COMPLETE REMOVAL OF THE POLLUTANT ION THAN COULD BE ACHIEVED BY SULFIDE PRECIPITATION OF THE POLLUTANT ALONE.
Inventors
- 👤 J Anderson
- 👤 C Weiss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:17
CPC Classifications
C; C01; C01G; C01G1/00; C01G1/12; C02; C02F; C02F1/00; C02F1/52; C02F1/5236; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912
Claims Analysis
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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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |