US3679557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hexavalent chromium reduction
Assignee: Calgon Corp
•
Filing: 1970-07-20
•
Granted: 1972-07-25
•
Expires: 1990-07-20
Abstract
Abstract DISCLOSED IS AN ELECTROCHEMICAL PROCESS OF REDUCING CR(VI) OTO CR(III) IN AQUEOUS SOLUTION. THE PH OF THE SOLUTION IS ADJUSTED TO ABOUT 1.5-3 AND SUBJECTED TO THE ACTION OF AN ELECTROLYTIC CELL BY PASSING THE SOLUTION THROUGH THE CELL AND HECE THE CATHODE THEREOF. THE CATHODE OF THE CELL IS MADE OF AN ELECTROLYTICALLY CONDUCTIVE MATERIAL, FOR INSTANCE CARBON, HAVING A HIGH SURFACE AREA PER UNIT VOLUME.
Inventors
- 👤 Patricia G Gilby
- 👤 William R Heineman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:34
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/46; C02F1/461; C02F1/467; C02F1/4676; C01; C01G; C01G37/00; C02F1/46104; C02F1/46109; C02F1/46114; C02F2001/46133; C02F2101/00; C02F2101/10; C02F2101/20; C02F2101/22; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/911; Y10S210/912; Y10S210/913
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |