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US4131454A
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Process for recovering silver and gold from chloride solutions
Assignee: Duisburger Kupferhuette
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Filing: 1977-11-02
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Granted: 1978-12-26
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Expires: 1997-11-02
Abstract
Abstract Process for selectively separating precious metal such as silver and gold from a chloride solution of the precious metals and other heavy metals which involves:
Inventors
- 👤 Norbert L. Piret
- 👤 Meinolf Hopper
- 👤 Herbert Kudelka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:28
CPC Classifications
C; C22; C22B; C22B3/00; C22B3/20; C22B3/44; C01; C01G; C01G5/00; C01G5/003; C01G7/00; C01G7/003; C22B3/22; C22B3/24; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
190 words
Process for selectively separating precious metal selected from the group consisting of gold, silver and mixtures thereof from a chloride solution of the precious metal and other heavy metal, the other heavy metal being the main constituent of the solution, which comprises: (a) adding to the solution finely divided activated carbon for reduction of gold in solution to gold metal and absorption of the gold metal by the carbon, thereafter, (b) adding an aqueous solution of an iodine compound for selective precipitation of further precious metal and the formation of an admixture of the precipitated metal in the solution, (c) the pH of the solution during steps (a) and (b) being such that hydrolysis with the metal ions does not occur, (d) the potential of the solution during step (b) being such that no substantial decomposition of the iodine compound occurs, (e) separating the precipitated precious metal and active carbon from the admixture formed in step (b), drying the separated precious metal and active carbon and admixing the dry product with an iodine binder and subjecting the resulting admixture to reduction for formation of a regulus containing the precious metal.
Claim 2
Dependent Claim
190 words
Process for selectively separating precious metal selected from the group consisting of gold, silver and mixtures thereof from a chloride solution of the precious metal and other heavy metal, the other heavy metal being the main constituent of the solution, which comprises: (a) adding to the solution finely divided activated carbon for reduction of gold in solution to gold metal and absorption of the gold metal by the carbon, thereafter, (b) adding an aqueous solution of an iodine compound for selective precipitation of further precious metal and the formation of an admixture of the precipitated metal in the solution, (c) the pH of the solution during steps (a) and (b) being such that hydrolysis with the metal ions does not occur, (d) the potential of the solution during step (b) being such that no substantial decomposition of the iodine compound occurs, (e) separating the precipitated precious metal and active carbon from the admixture formed in step (b), drying the separated precious metal and active carbon and admixing the dry product with an iodine binder and subjecting the resulting admixture to reduction for formation of a regulus containing the precious metal.
Claim 3
Dependent Claim
28 words
Process according to claim 1, wherein said other heavy metal includes at least one from the group consisting of copper, lead, zinc, nickel, cobalt, iron, magnesium, and aluminum.
Claim 4
Dependent Claim
14 words
Process of claim 1, wherein the main constituent in the chloride solution is lead.
Claim 5
Dependent Claim
14 words
Process of claim 1, wherein the main constituent in the chloride solution is copper.
Claim 6
Dependent Claim
12 words
Process of claim 1, wherein said pH value is kept below 3.0.
Claim 7
Dependent Claim
26 words
Process of claim 1, wherein said potential of the solution is provided by adding a reducer to the solution after step (a) and before step (b).
Claim 8
Dependent Claim
25 words
Process of claim 6, wherein there is a reducer which does not form or leave after reaction with the solution any solid substantial solid residue.
Claim 9
Dependent Claim
23 words
Process of claim 6, wherein the reducer is at least one from the group consisting of sulphur dioxide, zinc dust, and iron dust.
Claim 10
Dependent Claim
17 words
Process of claim 6, wherein the reducer is the aqueous iodide solution used in the third step.
Claim 11
Dependent Claim
26 words
Process of claim 1, wherein the temperature of the chloride solution in step (b) is below 50° C. and above the crystallization temperature of the solution.
Claim 12
Dependent Claim
11 words
Process of claim 7, wherein said temperature is below 40° C.
Claim 13
Dependent Claim
12 words
Process of claim 1, wherein the iodide compound is an alkali iodide.
Claim 14
Dependent Claim
26 words
Process of claim 1, wherein the amount of activated carbon added in step (a) is at least 5 times the gold concentration in the chloride solution.
Claim 15
Dependent Claim
27 words
Process as set forth in claim 1, wherein the amount of iodide added in step (b) is 100 to 150% the amount stoichiometrically equal to the silver.
Claim 16
Dependent Claim
38 words
Process of claim 1, wherein said precious metal is gold and the chloride solution is free of silver, and the amount of iodide added in step (b) is up to 100% the amount stoichiometrically equal to the gold.
Claim 17
Dependent Claim
23 words
Process as set forth in claim 1, wherein the iodine binder is at least one of alkali oxide, alkali hydroxide and alkali carbonate.
Claim 18
Dependent Claim
16 words
Process of claim 1, wherein the solution contains sulphate ions and is a predominately chloride solution.
Claim 19
Dependent Claim
15 words
Process of claim 1, wherein said pH of the solution is between 1.0 and 2.0.
Claim 20
Dependent Claim
26 words
Process of claim 1, wherein the amount of activated carbon added in step (a) is 10 to 30 times the gold concentration in the chloride solution.
Claim 21
Dependent Claim
24 words
Process of claim 1, wherein the amount of iodide added in step (b) is 110 to 120% the amount stoichiometrically equal to the silver.
Claim 22
Dependent Claim
38 words
Process of claim 1, wherein said precious metal is gold and the chloride solution is free of silver, and the amount of iodide added in step (b) is 50 to 100% the amount stoichiometrically equal to the gold.
Claim 23
Dependent Claim
12 words
Process of claim 1, wherein the precious metal is silver and gold.
Claim 24
Dependent Claim
89 words
Process of claim 1, wherein said precious metal is silver and gold, the pH value is kept below 3.0, the temperature of the chloride solution in step (b) is below 50° C. and above the crystallization temperature of the solution, the iodide compound is an alkali iodide, wherein the amount of activated carbon added in step (a) is at least 5 times the gold concentration in the chloride solution, and the amount of iodide added in step (b) is 100 to 150% the amount stoichiometrically equal to the silver.
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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) | 1981-12-25 | 1982-06-26 | 1982-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-25 | 1986-06-26 | 1986-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-25 | 1990-06-26 | 1990-12-26 | $7700.00 | Window Closed / Lapsed |