Patent US4902345A successfully refreshed from Google Patents.
US4902345A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of refractory carbonaceous and sulfidic ores or concentrates for precious metal recovery
Assignee: Newmont Gold Co
•
Filing: 1989-01-12
•
Granted: 1990-02-20
•
Expires: 2009-01-12
Abstract
Abstract The recovery of precious metals from refractory carbonaceous and sulfidic ores or concentrates is improved by subjecting an oxidized slurry of this type of ore to thiourea leaching in the presence of carbon instead of subjecting the slurry to cyanidation leaching.
Inventors
- 👤 Brian Ball
- 👤 Rong-yu Wan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:26
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
59 words
A method for the recovery of a precious metal from carbonaceous and sulfidic ores or concentrates which comprises: (a) forming an aqueous slurry of said ores or concentrates; (b) pretreating said aqueous slurry in an autoclave with an oxygen-containing gas; (c) leaching said precious metal with thiourea in the presence of added carbon; and (d) recovering said precious metal.
Claim 2
Independent Claim
59 words
A method for the recovery of a precious metal from carbonaceous and sulfidic ores or concentrates which comprises: (a) forming an aqueous slurry of said ores or concentrates; (b) pretreating said aqueous slurry in an autoclave with an oxygen-containing gas; (c) leaching said precious metal with thiourea in the presence of added carbon; and (d) recovering said precious metal.
Claim 3
Dependent Claim
36 words
The method as defined in claim 1, wherein said pretreating is with sufficient oxygen overpressure at a temperature and time sufficient to oxidize pyritic sulfides and sulfides associated with metallic components in said ores or concentrates.
Claim 4
Dependent Claim
31 words
The method as defined in claim 2 wherein chlorine gas, chlorite or a chemical agent which will supply chlorine to said aqueous slurry is used as a supplement to the pre-treatment.
Claim 5
Dependent Claim
13 words
The method as defined in claim 2, wherein said precious metal is gold.
Claim 6
Dependent Claim
24 words
The method as defined in claim 4, wherein said pretreating in an autoclave is for 2 hours at between about 110° and 250° C.
Claim 7
Dependent Claim
21 words
The method as defined in claim 4, wherein the recovery is from ore which contains base metal sulfides and carbonaceous material.
Claim 8
Dependent Claim
31 words
The method as defined in claim 4, wherein the recovery is from concentrates which contain at least about 2.0% by weight sulfide sulfur and a least 0.75% by weight organic carbon.
Claim 9
Dependent Claim
103 words
The method as defined in claim 4, wherein the ore is wet ground with water to yield a slurry containing said ore in a mesh size of about 60% of -200 mesh; said ore is thereafter pulped to wherein the sam contains from about 40 to about 50% by weight of solids; said slurry is heated and treated in an autoclave at a temperature between about 110° and 250° C. in the presence of oxygen; the oxidized aqueous slurry is cooled to about 20° to 60° C.; and gold is extracted from said oxidized aqueous slurry with thiourea in the presence of carbon.
Claim 10
Dependent Claim
22 words
The method as defined in claim 8 wherein the concentration of thiourea is from 2 grams/liter to 20 gram/liter in the slurry.
Claim 11
Dependent Claim
25 words
The method as defined in claim 4 wherein ferric ion is added when the precious metal is leached with thiourea in the presence of carbon.
Claim 12
Independent Claim
29 words
The method as defined in wherein a reducing agent is added to control the oxidation potential when the precious metal is leached with thiourea in the presence of carbon.
Claim 13
Independent Claim
29 words
The method as defined in wherein a reducing agent is added to control the oxidation potential when the precious metal is leached with thiourea in the presence of carbon.
References Cited (Backward Citations)
US4145212A
Cited
US4289532A
Cited
US4259107A
Cited
US4561947A
Cited
US4552589A
Cited
US4629502A
Cited
US4738718A
Cited
US4778519A
Cited
US4801329A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |