Patent US3772194A successfully refreshed from Google Patents.
US3772194A
Expired / Lapsed
US
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Silver catalyzed oxidation of complex metal cyanides
Assignee: Eastman Kodak Co
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Filing: 1972-06-21
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Granted: 1973-11-13
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Expires: 1992-06-21
Abstract
Abstract A method of conditioning waste containing complex cyanide compounds and oxidizing at least the complex iron cyanides, e.g. hexacyanoferrates, comprising chlorinating the waste in the presence of a silver ion catalyst (present as a soluble silver salt such as AgNO3, AgCl2, etc.) to convert the cyanide to a nontoxic compound is described. Chlorination is preferably carried out at a temperature of between about 25* and 68* C in an alkaline medium, using an excess of free chlorine or hypochlorite as the chlorinating agent.
Inventors
- 👤 H Baden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:23
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/72; C02F1/76
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
15 words
The process of claim 1 wherein said chlorination is carried out at an alkaline pH.
Claim 2
Dependent Claim
18 words
The process of claim 1 wherein said chlorination is carried out at a pH of greater than 10.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein said chlorination is carried out at a pH of at least 11.5.
Claim 4
Dependent Claim
20 words
The process of claim 1 wherein said chlorination is carried out at a temperature of about 25*C to about 68*C.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein said chlorination is carried out at a temperature of 61*C to 68*C.
Claim 6
Dependent Claim
30 words
The process of claim 1 wherein said chlorination is carried out while maintaining an excess of chlorine of at least about 0.5 grams of free chlorine per liter of solution.
Claim 7
Dependent Claim
18 words
The process of claim 1 wherein said chlorination is carried out by bubbling chlorine gas through said solution.
Claim 8
Dependent Claim
21 words
The process of claim 1 wherein said chlorination is carried out by using an alkali metal hypochlorite as the chlorinating agent.
Claim 9
Dependent Claim
19 words
The process of claim 1 wherein said chlorination is carried out by using sodium hypochlorite as the chlorinating agent.
Claim 10
Dependent Claim
29 words
The process of claim 1 wherein said chlorination is carried out with from about 0.1 to about 10 grams per liter of solution of a silver salt as catalyst.
Claim 11
Dependent Claim
19 words
The process of claim 1 wherein said chlorination is carried out with the use of silver nitrate as catalyst.
Claim 12
Dependent Claim
15 words
The process of claim 1 wherein said solution is a waste photographic ferricyanide bleach solution.
References Cited (Backward Citations)
US2981682A
Cited
US3615507A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |