US3632336A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silver recovery process
Assignee: Battelle Development Corp
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Filing: 1969-07-25
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Granted: 1972-01-04
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Expires: 1989-07-25
Abstract
Abstract Silver from used manufactured organic materials such as photographic film, sensitized paper and printed circuit boards, is recovered by placing the material in an enclosed retort and subjecting the retort to a noncombustible atmosphere such as steam and then increasing the temperature of the material to a final temperature between 500* and 960* C. to vaporize the volatile constituents and carbonize the organic material to leave a silver and carbon residue. The silver is then separated from the carbon by burning the carbon in a combustible atmosphere to transform the residue into silver and ash. The silver and resulting ash may be efficiently separated by conventional flux or flotation processes.
Inventors
- 👤 Eric C Cameron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:28
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/02; C22B11/021; C22B11/025; C22B11/04; C22B11/042; C22B11/046; C22B7/00; C22B7/009; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
16 words
A silver recovery process as defined in claim 1 wherein the noncombustible atmosphere includes superheated steam.
Claim 2
Dependent Claim
20 words
A silver recovery process as dEfined in claim 2 wherein the noncombustible atmosphere has a pressure less than 15 p.s.i.g.
Claim 3
Dependent Claim
32 words
A silver recovery process as defined in claim 1 wherein the temperature of the materials is progressively increased to a final temperature above 350* C. and below the melting point of silver.
Claim 4
Dependent Claim
36 words
A silver recovery process as defined in claim 1 wherein the temperature of the materials is progressively increased to heat the materials to a final temperature above 500* C. and below the melting point of silver.
Claim 5
Dependent Claim
43 words
A silver recovery process as defined in claim 1 wherein the silver and carbon residue are separated by burning the silver and carbon residue in an oxidizing atmosphere to produce a silver and ash residue and separating the silver from the ash residue.
Claim 6
Dependent Claim
23 words
A silver recovery process as defined in claim 1 wherein the organic material is printed circuit boards having conductive elements of silver therein.
Claim 7
Dependent Claim
79 words
A silver recovery process for recovering silver from used photographic materials such as film and paper, that includes the steps of: a. subjecting the used photographic material to a noncombustible atmosphere; b. progressively increasing the temperature of the used photographic material to a temperature below the melting point of silver which is sufficient to vaporize and carbonize the used photographic material except the silver to form a residual silver and carbon residue; and c. separating the silver and carbon.
Claim 8
Dependent Claim
33 words
A silver recovery process as defined in claim 8 wherein the temperature of the used photographic material is progressively increased to a temperature above 500* C. and below the melting point of silver.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |