US4208378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Desorption of gold from activated carbon
Assignee: United States Department of the Interior
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Filing: 1977-04-11
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Granted: 1980-06-17
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Expires: 1997-04-11
Abstract
Abstract Gold is desorbed from activated carbon by contacting, at a temperature of about 70° to 160° C., with a solution comprising about 20 to 30 percent by volume of a water soluble alcohol and about 80 to 70 percent by volume of an aqueous solution of a strong base.
Inventors
- 👤 Harold J. Heinen
- 👤 David G. Peterson
- 👤 Roald E. Lindstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:26
CPC Classifications
C; C01; C01G; C01G7/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
A process for desorption of gold from an activated carbon loaded by treatment with a leach solution containing calcium or sodium cyanide and lime comprising contacting the carbon with stripping solution consisting essentially of about 20 to 30 percent by volume of a water soluble alcohol and about 80 to 70 percent by volume of an aqueous solution of a strong base, the operating temperature being about 80° to 90° C.
Claim 2
Dependent Claim
71 words
A process for desorption of gold from an activated carbon loaded by treatment with a leach solution containing calcium or sodium cyanide and lime comprising contacting the carbon with stripping solution consisting essentially of about 20 to 30 percent by volume of a water soluble alcohol and about 80 to 70 percent by volume of an aqueous solution of a strong base, the operating temperature being about 80° to 90° C.
Claim 3
Dependent Claim
15 words
The process of claim 1 in which the alcohol is methanol, ethanol, propanol, or isopropanol.
Claim 4
Dependent Claim
28 words
The process of claim 1 in which the aqueous solution of the strong base contains the base in an amount of about 1 to 2 percent by weight.
Claim 5
Dependent Claim
16 words
The process of claim 3 in which the strong base is sodium hydroxide or potassium hydroxide.
Claim 6
Dependent Claim
20 words
The process of claim 1 in which the alcohol is employed in an amount of about 20 percent by volume.
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) | 1983-06-17 | 1983-12-17 | 1984-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-17 | 1987-12-17 | 1988-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-17 | 1991-12-17 | 1992-06-17 | $7700.00 | Window Closed / Lapsed |