US4269622A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of precious metals from difficult ores
Assignee: KERLEY ENTERPRISES Inc
•
Filing: 1979-12-28
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Granted: 1981-05-26
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Expires: 1999-12-28
Abstract
Abstract Precious metals such as gold and silver are recovered from difficult-to-treat ores, particularly those containing manganese, by lixiviating using an ammonium thiosulfate leach solution containing copper, sufficient ammonia to maintain a pH of at least 7.5, and at least 0.05% sulfite ion.
Inventors
- 👤 Bernard J. Kerley, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:42
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
82 words
In a method for the recovery of precious metals including gold and silver from an ore containing same, comprising lixiviating said precious metals from said ore using an ammonium thiosulfate liquor as the lixiviating agent in the presence of copper, followed by recovering said precious metals from said ammonium thiosulfate liquor, the improvement comprising: maintaining the pH of said liquor during lixiviation at a value of at least 7.5 with ammonia, and simultaneously maintaining a sulfite ion concentration of at least 0.05%.
Claim 2
Dependent Claim
82 words
In a method for the recovery of precious metals including gold and silver from an ore containing same, comprising lixiviating said precious metals from said ore using an ammonium thiosulfate liquor as the lixiviating agent in the presence of copper, followed by recovering said precious metals from said ammonium thiosulfate liquor, the improvement comprising: maintaining the pH of said liquor during lixiviation at a value of at least 7.5 with ammonia, and simultaneously maintaining a sulfite ion concentration of at least 0.05%.
Claim 3
Dependent Claim
29 words
A method in accordance with claim 1, wherein said ore is a manganese containing ore and said sulfite ion concentration is maintained at a level of at least 0.1%.
Claim 4
Dependent Claim
24 words
A method in accordance with claim 1, wherein said ore contains at least 0.5% manganese and said sulfite ion concentration is maintained at 1-4%.
Claim 5
Dependent Claim
24 words
A process in accordance with claim 1, wherein the sulfite ion concentration is maintained by generation in situ from the addition of sulfur dioxide.
Claim 6
Dependent Claim
15 words
A method in accordance with claim 1, wherein the temperature is maintained at 40°-60° C.
Claim 7
Dependent Claim
43 words
A method in accordance with claim 1, wherein after said recovery of said precious metals, said ammonium thiosulfate liquor is recycled and additional thiosulfate is generated in situ by adding extra sulfite and sulfide, and reacting the same to form the additional thiosulfate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |