US4177068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extraction of gold and silver
Assignee: Foster Wheeler Energy Corp
•
Filing: 1978-02-27
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Granted: 1979-12-04
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Expires: 1998-02-27
Abstract
Abstract A process for the extraction of gold and silver from their ores in which the ore is reduced to a particle size of 1 mm or less and mixed with a lixiviant, e.g., alkaline sodium or potassium cyanide, in an amount to provide a liquor content of about 8 to 12%, the lixiviant coated particles are allowed to react for a time sufficient for the lixiviant to extract the noble metal and the particles washed with water to obtain a solution of the noble metal salt from which the noble metal is recovered.
Inventors
- 👤 Ramachandran Balakrishnan
- 👤 Geoffrey F. Skinner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:52
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
185 words
A process for the extraction of a noble metal selected from the group consisting of gold and silver from their respective ores comprising the steps of: (a) reducing said ore to a particle size of about 1 mm or less, (b) mixing said particles with an alkaline solution having a concentration of from 0.10 to 5% by weight of lixiviant for said noble metal such lixiviant selected from the group consisting of sodium cyanide and potassium cyanide in an amount to provide a liquor content of from 8 to 12% by weight of the mixture of lixiviant and ore, the concentration of said lixiviant being sufficient to solubilize all said noble metal in the ore and any other lixiviant consuming materials present, (c) allowing the mixture from step (b) to react in a static bed at a temperature of 10° to 40° C. for a period between 12 and 48 hours and sufficient for the lixiviant to extract said noble metal, while said bed is being aerated, (d) reslurrying said bed with water, and (e) filtering the solution from step (d) to recover said metal.
Claim 2
Dependent Claim
185 words
A process for the extraction of a noble metal selected from the group consisting of gold and silver from their respective ores comprising the steps of: (a) reducing said ore to a particle size of about 1 mm or less, (b) mixing said particles with an alkaline solution having a concentration of from 0.10 to 5% by weight of lixiviant for said noble metal such lixiviant selected from the group consisting of sodium cyanide and potassium cyanide in an amount to provide a liquor content of from 8 to 12% by weight of the mixture of lixiviant and ore, the concentration of said lixiviant being sufficient to solubilize all said noble metal in the ore and any other lixiviant consuming materials present, (c) allowing the mixture from step (b) to react in a static bed at a temperature of 10° to 40° C. for a period between 12 and 48 hours and sufficient for the lixiviant to extract said noble metal, while said bed is being aerated, (d) reslurrying said bed with water, and (e) filtering the solution from step (d) to recover said metal.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein said noble metal is gold.
Claim 4
Dependent Claim
31 words
A process according to claim 2 wherein the lixiviant is present in an amount to provide a liquor content of about 10% by weight of the mixture of lixiviant and ore.
Claim 5
Dependent Claim
15 words
A process according to claim 2 wherein step (a) and step (b) are performed simultaneously.
Claim 6
Dependent Claim
18 words
A process according to claim 2 wherein said solution has a concentration of 0.25 to 2% by weight.
Claim 7
Dependent Claim
17 words
A process according to claim 2 wherein said noble metal is recovered from solution by zinc cementation.
Claim 8
Dependent Claim
16 words
A process according to claim 2 wherein said noble metal is recovered from solution by electrolysis.
Claim 9
Dependent Claim
65 words
The process defined in claim 1 wherein said noble metal is gold, said ore is an auriferous ore, said ore is reduced to a particle size of the order of 1 mm, said lixiviant is sodium cyanide, said solution is at a concentration of 0.25 to 2% by weight and the liquor content of the mixture of lixiviant and ore is approximately 10% by weight.
References Cited (Backward Citations)
US683325A
Cited
US1103346A
Cited
US2112299A
Cited
US2131535A
Cited
US2304427A
Cited
US3808306A
Cited
US3777004A
Cited
US3709680A
Cited
US4017309A
Cited
US4070182A
Cited
US4072587A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-03 | 1983-06-04 | 1983-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-03 | 1987-06-04 | 1987-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-03 | 1991-06-04 | 1991-12-04 | $7700.00 | Window Closed / Lapsed |