US4372830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of gold in gold plating processes
Assignee: Nokia of America Corp
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Filing: 1982-03-18
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Granted: 1983-02-08
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Expires: 2002-03-18
Abstract
Abstract A process is described involving gold in which gold cyanide ion (e.g., potassium gold cyanide) is removed from an aqueous solution (typically a water rinse solution) by absorption on an anion-exchange resin and the gold cyanide ion is then removed from the resin using an eluent solution comprising organic solvent, water and thiocyanate ion. This procedure is convenient and leads to virtually complete removal of gold from the resin. Because of the low volume of eluent solution required to remove the gold cyanide ion, the procedure can be used to efficiently produce crystalline potassium gold cyanide from highly dilute aqueous solutions.
Inventors
- 👤 Henry H. Law
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:35
CPC Classifications
C; C01; C01G; C01G7/00; C01G7/003; C01C; C01C3/00; C01C3/08; C01C3/11; C22; C22B; C22B3/00; C22B3/20; C22B3/42; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
110 words
A process involving the use of gold in the form of gold cyanide ion dissolved in aqueous solution where gold cyanide ion is recovered from at least a portion of the aqueous solution by absorption on an anion-exchange resin and the gold is removed from the resin using an eluent characterized in that the eluent comprises at least 0.1 molar thiocyanate ion, 5-95 weight percent organic solvent and water and the organic solvent consists essentially of at least one organic compound selected from the group consisting of formamide, dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methyl-2-pyrrolidone, acetonitrile, acetone, tetrahydrofuran, diethylacetamide, diethylformamide, triethylphosphate, trimethylphosphate, tributylphosphate, dimethoxyethane, ethylamine, ethylenediamine, triethylamine, propylene carbonate, dioxane, pyridine and dioxolane.
Claim 2
Dependent Claim
110 words
A process involving the use of gold in the form of gold cyanide ion dissolved in aqueous solution where gold cyanide ion is recovered from at least a portion of the aqueous solution by absorption on an anion-exchange resin and the gold is removed from the resin using an eluent characterized in that the eluent comprises at least 0.1 molar thiocyanate ion, 5-95 weight percent organic solvent and water and the organic solvent consists essentially of at least one organic compound selected from the group consisting of formamide, dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methyl-2-pyrrolidone, acetonitrile, acetone, tetrahydrofuran, diethylacetamide, diethylformamide, triethylphosphate, trimethylphosphate, tributylphosphate, dimethoxyethane, ethylamine, ethylenediamine, triethylamine, propylene carbonate, dioxane, pyridine and dioxolane.
Claim 3
Dependent Claim
18 words
The process of claim 1 in which the concentration of thiocyanate ion ranges from 1 to 5 molar.
Claim 4
Dependent Claim
17 words
The process of claim 2 in which the thiocyanate ion is in the form of alkali-metal thiocyanate.
Claim 5
Dependent Claim
13 words
The process of claim 3 in which the alkali-metal thiocyanate is potassium thiocyanate.
Claim 6
Dependent Claim
21 words
The process of claim 1 in which the weight percent of organic solvent in the eluent ranges from 25 to 75.
Claim 7
Dependent Claim
31 words
The process of claim 1 in which the organic solvent consists essentially of at least one organic compound selected from the group consisting of dimethylformamide, dimethylacetamide, acetone, N-methyl-2-pyrrolidone, dimethylsulfoxide and tetrahydrofuran.
Claim 8
Dependent Claim
14 words
The process of claim 6 in which the organic solvent consists essentially of dimethylformamide.
Claim 9
Dependent Claim
18 words
The process of claim 7 in which the concentration of dimethylformamide in water is 50 (±10) weight percent.
Claim 10
Dependent Claim
19 words
The process of claim 1 in which the anion-exchange resin is the strongly-basic type with quaternary ammonium functional groups.
Claim 11
Dependent Claim
19 words
The process of claim 1 in which the process involving the use of gold is a gold electroplating process.
Claim 12
Dependent Claim
47 words
The process of claim 1 in which the eluent is heated to a temperature range between 40 and 80 degrees C. in removing the gold cyanide ion from the anion-exchange resin and cooled to below 40 degrees C. to remove the gold cyanide ion from the eluent.
Claim 13
Dependent Claim
16 words
The process of claim 1 in which the gold is recovered from the eluent by electroplating.
Claim 14
Dependent Claim
17 words
The process of claim 1 in which the gold is recovered from the eluent by chemical reduction.
Claim 15
Dependent Claim
31 words
The process of claim 1 in which the thiocyanate ion is in the form of ammonium thiocyanate and the gold cyanide ion recovered is in the form of ammonium gold cyanide.
Claim 16
Dependent Claim
15 words
The process of claim 1 in which the aqueous solution is a gold plating bath.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-07 | 1986-08-09 | 1987-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-07 | 1990-08-09 | 1991-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-07 | 1994-08-09 | 1995-02-08 | $7700.00 | Window Closed / Lapsed |