US3635697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of gold
Assignee: United States Department of the Interior
•
Filing: 1969-09-30
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Granted: 1972-01-18
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Expires: 1989-09-30
Abstract
Abstract Gold is recovered from dilute solution by complexing with malononitrile, followed by sorption on, and elution from, an anion-exchange resin having both weakly basic and strongly basic groups.
Inventors
- 👤 Bernard J Scheiner
- 👤 Roald E Lindstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:24
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/08; C01; C01G; C01G7/00; C01G7/003; C22B3/00; C22B3/20; C22B3/42; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
25 words
The method of claim 1 in which the solution of malononitrile-gold complex is formed by leaching of gold ores with an aqueous solution of malononitrile.
Claim 2
Dependent Claim
22 words
The method of claim 1 in which the pH of the aqueous solution of malononitrile-gold complex is from about 10 to 12.
Claim 3
Dependent Claim
30 words
The method of claim 1 in which the weakly basic amine groups of the anion-exchange resin are tertiary amine groups and the strongly basic amine groups are quaternary ammonium groups.
Claim 4
Dependent Claim
13 words
The method of claim 1 in which the mineral acid is sulfuric acid.
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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |