US3705716A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Monitoring silver recovery
Assignee: Eastman Kodak Co
•
Filing: 1971-07-09
•
Granted: 1972-12-12
•
Expires: 1991-07-09
Abstract
Abstract Silver is recovered from a photographic processing solution by passing the solution through a mass of steel wool in a recovery vessel. The effluent electrolyte from the vessel is then passed through a voltaic cell wherein one of the electrodes is iron in the form of steel wool. When the steel wool in the recovery vessel has lost its power to efficiently remove silver, silver ions appear in the effluent electrolyte in increasing concentration. Upon the generation of a predetermined value of electrical current in the voltaic cell representing a predetermined silver concentration, the recovery unit is disconnected and sent off for refining of the contained silver.
Inventors
- 👤 Thomas N Hendrickson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:54
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; C22B11/042; C22B11/046; C25; C25C; C25C1/00; C25C1/20; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
68 words
Apparatus in accordance with claim 1 wherein said means is a cell, two spaced electrodes in said cell adapted to be immersed in electrolyte, a first one of said electrodes comprising said metal above silver in the electromotive force series, an electrical circuit connecting said electrodes together externally of said cell, and a device in said electrical circuit for indicating the flow of electrical current in said circuit.
Claim 2
Dependent Claim
39 words
Apparatus in accordance with claim 1 wherein said outlet conduit is connected to said cell for continuously feeding the entire effluent electrolyte from said vessel thereto, and wherein said cell has an outlet for discharging said electrolyte continuously therefrom.
Claim 3
Dependent Claim
24 words
Apparatus in accordance with claim 2 wherein said first one of said electrodes and said metallic filler both comprise a mass of steel wool.
Claim 4
Dependent Claim
12 words
Apparatus in accordance with claim 2 wherein said device is a voltmeter.
Claim 5
Dependent Claim
68 words
Apparatus in accordance with claim 1 wherein said means comprises a cell containing two spaced electrodes, a first one of said electrodes comprising the same metal as said metallic filler, said cell being adapted to receive effluent electrolyte from said outlet conduit, and electric current indicating means externally of said cell and connected to said electrodes to complete an electrical circuit with effluent electrolyte flowing into said cell.
References Cited (Backward Citations)
US3616412A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-12 | 1976-06-12 | 1976-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-12 | 1980-06-12 | 1980-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-12 | 1984-06-12 | 1984-12-12 | $7700.00 | Window Closed / Lapsed |