Patent US4645535A successfully refreshed from Google Patents.
US4645535A
Expired / Lapsed
US
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Method for the recovery of precious metals from ores
Assignee: KLS Inc A CORP OF SOUTH DAKOTA
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Filing: 1985-08-15
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Granted: 1987-02-24
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Expires: 2005-08-15
Abstract
Abstract A process for the recovery of precious metals from ore containing the same is disclosed. The process includes the formation of a lixiviant solution including a thiourea compound, urea and potassium lignin sulfonate. The ore is then exposed to this lixiviant solution to extract the precious metals therefrom, and the dissolved precious metals are then recovered from the solution.
Inventors
- 👤 Roger H. Little
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:14
CPC Classifications
C; C01; C01G; C01G7/00; C01G7/003; C22; C22B; C22B11/00; C22B11/04; C22B3/00; C22B3/20; C22B3/22; C22B3/24; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
49 words
A process for the recovery of precious metals from ore containing the same comprising: forming a lixiviant solution including a thiourea compound, urea and potassium lignin sulfonate; exposing the ore to said lixiviant solution to extract the precious metals therefrom; and recovering the dissolved precious metals from said solution.
Claim 2
Dependent Claim
49 words
A process for the recovery of precious metals from ore containing the same comprising: forming a lixiviant solution including a thiourea compound, urea and potassium lignin sulfonate; exposing the ore to said lixiviant solution to extract the precious metals therefrom; and recovering the dissolved precious metals from said solution.
Claim 3
Dependent Claim
16 words
The process as claimed in claim 1, wherein the pH of said lixiviant solution is acidic.
Claim 4
Dependent Claim
13 words
The process as claimed in claim 2, wherein said pH is approximately 1.0-1.5.
Claim 5
Dependent Claim
14 words
The process as claimed in claim 1, wherein said lixiviant solution includes ferric sulfate.
Claim 6
Dependent Claim
24 words
The process as claimed in claim 1, wherein said lixiviant solution comprises an aqueous solution of thiourea, ferric sulfate, potassium lignin sulfonate and urea.
Claim 7
Dependent Claim
19 words
The process as claimed in claim 5, wherein the pH of said lixiviant solution is maintained at approximately 1.0-1.5.
Claim 8
Dependent Claim
46 words
The process as claimed in claim 1, wherein said dissolved precious metals are recovered by passing the lixiviant solution containing said dissolved precious metals through a packed bed extraction column to remove the precious metals from solution, and recovering the precious metals from said packed bed.
Claim 9
Dependent Claim
29 words
The process as claimed in claim 7, wherein said packed bed comprises an agent selected from the group consisting of activated charcoal, powdered aluminum, powdered lead, and powdered zinc.
Claim 10
Dependent Claim
36 words
The process as claimed in claim 1, wherein said ore remains in contact with said lixiviant solution for approximately 2-6 hours, said solution extracting at least approximately 98 percent of the precious metals from said ore.
Claim 11
Dependent Claim
15 words
The process as claimed in claim 1, wherein said precious metals comprise gold and silver.
Claim 12
Dependent Claim
13 words
The process as claimed in claim 1, wherein said thiourea compound comprises thiourea.
Claim 13
Dependent Claim
20 words
The process as claimed in claim 1, wherein the ratio of urea to thiourea is between about 1:9 and 9:1.
Claim 14
Dependent Claim
34 words
The process as claimed in claim 1, wherein the concentration of the potassium lignin sulfonate is not less than about twenty per cent of the concentration of the thiourea compound and the urea together.
Claim 15
Dependent Claim
75 words
In a process for recovering precious metals from ore containing the same wherein said precious metals are lixiviated from said ore by a lixiviant containing a thiourea compuound and subsequently deposited in a packed bed extraction column, the improvement comprising adding urea and potassium lignin sulfonate to said thiourea lixiviant to increase the extraction of said precious metals by said lixiviant and to increase the recovery rate of dissolved precious metals by said extraction column.
Claim 16
Dependent Claim
75 words
In a process for recovering precious metals from ore containing the same wherein said precious metals are lixiviated from said ore by a lixiviant containing a thiourea compuound and subsequently deposited in a packed bed extraction column, the improvement comprising adding urea and potassium lignin sulfonate to said thiourea lixiviant to increase the extraction of said precious metals by said lixiviant and to increase the recovery rate of dissolved precious metals by said extraction column.
Claim 17
Dependent Claim
25 words
The process as claimed in claim 14, wherein ferric sulfate is also added to said thiourea lixiviant along with said urea and potassium lignin sulfonate.
Claim 18
Dependent Claim
33 words
The process as claimed in claim 14, wherein the pH of said thiourea lixiviant is maintained strongly acidic after the addition of said urea and potassium lignin sulfonate by adding an acid thereto.
Claim 19
Dependent Claim
13 words
The process as claimed in claim 16 wherein the acid comprises sulphuric acid.
Claim 20
Dependent Claim
15 words
The process as claimed in claim 14, wherein said pH is maintained at approximately 1.0-1.5.
Claim 21
Dependent Claim
13 words
The process as claimed in claim 18 wherein the acid comprises sulphuric acid.
Claim 22
Dependent Claim
24 words
The process as claimed in claim 14, wherein the resultant lixiviant comprises an aqueous solution of thiourea, ferric sulfate, urea, and potassium lignin sulfonate.
Claim 23
Dependent Claim
27 words
The process as claimed in claim 20, wherein the pH of said aqueous solution is maintained at a level of approximately 1.0-1.5 by adding an acid thereto.
Claim 24
Dependent Claim
13 words
The process as claimed in claim 21 wherein the acid comprises sulphuric acid.
Claim 25
Dependent Claim
31 words
The process as claimed in claim 14, wherein said packed bed comprises a powdered deposition agent selected from the group consisting of activated charcoal, powdered aluminum, powered zinc, and powdered lead.
Claim 26
Dependent Claim
15 words
The process as claimed in claim 14, wherein said precious metals comprise silver and gold.
Claim 27
Dependent Claim
30 words
The process as claimed in claim 14, wherein the ratio of urea to thiourea in the lixiviant after the urea has been added thereto is between about 1:9 and 9:1.
Claim 28
Dependent Claim
34 words
The process as claimed in claim 14, wherein the concentration of the potassium lignin sulfonate is not less than about twenty per cent of the concentration of the thiourea compound and the urea together.
Claim 29
Dependent Claim
35 words
A process for increasing the precious metal extraction capability of a lixiviant containing a thiourea compound when subjecting an ore containing said precious metals to said lixiviant, said process comprising adding urea to said lixiviant.
Claim 30
Dependent Claim
35 words
A process for increasing the precious metal extraction capability of a lixiviant containing a thiourea compound when subjecting an ore containing said precious metals to said lixiviant, said process comprising adding urea to said lixiviant.
Claim 31
Dependent Claim
16 words
The process as claimed in claim 27, wherein ferric sulfate is also added to said lixiviant.
Claim 32
Dependent Claim
40 words
The process as claimed in claim 27, wherein said lixiviant comprises an aqueous solution of thiourea, and wherein a sufficient amount of urea is added to produce a lixiviant solution containing approximately equal amounts of urea and the thiourea compound.
Claim 33
Dependent Claim
22 words
The process as claimed in claim 27, wherein the pH of said lixiviant is maintained strongly acidic by adding an acid thereto.
Claim 34
Dependent Claim
13 words
The process as claimed in claim 30, wherein the acid comprises sulphuric acid.
Claim 35
Dependent Claim
15 words
The process as claimed in claim 30, wherein said pH is maintained at approximately 1.0-1.5.
Claim 36
Dependent Claim
13 words
The process as claimed in claim 32 wherein the acid comprises sulphuric acid.
Claim 37
Dependent Claim
30 words
The process as claimed in claim 27, wherein potassium lignin sulfonate is also added to said lixiviant to increase the subsequent recovery of dissolved precious metals from said lixiviant solution.
Claim 38
Dependent Claim
24 words
The process as claimed in claim 27, wherein said ore is subjected to said lixiviant for approximately 2-6 hours after said urea is added.
Claim 39
Dependent Claim
15 words
The process as claimed in claim 27, wherein said precious metals comprise silver and gold.
Claim 40
Dependent Claim
54 words
A process for increasing the recovery rate of dissolved precious metals from a lixiviant solution by a packed bed extraction column when passing said solution through said bed to deposit the precious metals thereon, said process comprising adding potassium lignin sulfonate to said lixiviant solution prior to passing said solution through said packed bed.
Claim 41
Dependent Claim
54 words
A process for increasing the recovery rate of dissolved precious metals from a lixiviant solution by a packed bed extraction column when passing said solution through said bed to deposit the precious metals thereon, said process comprising adding potassium lignin sulfonate to said lixiviant solution prior to passing said solution through said packed bed.
Claim 42
Dependent Claim
19 words
The process as claimed in claim 37, wherein said potassium lignin sulfonate is added prior to lixiviating said ore.
Claim 43
Dependent Claim
32 words
The process as claimed in claim 38, wherein urea is also added with said potassium lignin sulfonate prior to lixiviating said ore to increase the extraction of said metals by said lixiviant.
Claim 44
Dependent Claim
21 words
The process as claimed in claim 39, wherein ferric sulfate is added along with said urea and said potassium lignin sulfonate.
Claim 45
Dependent Claim
23 words
The process as claimed in claim 37, wherein the pH of said lixiviant solution is maintained strongly acidic by adding an acid thereto.
Claim 46
Dependent Claim
13 words
The process as claimed in claim 41 wherein the acid comprises sulphuric acid.
Claim 47
Dependent Claim
15 words
The process as claimed in claim 37, wherein said precious metals comprise silver and gold.
Claim 48
Dependent Claim
31 words
The process as claimed in claim 37, wherein said packed bed comprises a powdered deposition agent selected from the group consisting of activated charcoal, powdered aluminum, powdered zinc, and powdered lead.
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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) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |