Claims
- 1. A bath for producing deposits of gold by electrodeposition, comprising: an aqueous solution containing at least one soluble gold cyanide compound; formic acid in a concentration of at least 20 ml/l to about 150 ml/l of said bath solution, said formic acid concentrations being calculated on a 90% by weight grade of formic acid; a cobalt compound; sufficient alkali to bring the pH to within the range of 3.5 to 4.4; and as conductivity salts and inhibitors, malic acid or a combination thereof with gluconic acid or with a water soluble organophosphorous chelating agent, said conductivity chelating agent, said conductivity salts and inhibitors being present in at least sufficient quantity to provide a specific gravity of at least 13 Baume' in said bath.
- 2. A bath as set forth in claim 1, in which the conductivity salt and inhibitor is malic acid in concentrations of about 75 to 150 g/l.
- 3. A bath as set forth in claim 1, in which the conductivity salt and inhibitor is a combination of said organophosphorus chelating agent with malic acid.
- 4. A bath as set forth in claim 1, in which the conductivity salt and inhibitor is a combination of malic acid and gluconic acid.
- 5. A bath as set forth in claim 1 in which the formic acid concentration is above 40 ml to about 90 ml/liter.
- 6. A bath as set forth in claim 1 in which the formic acid concentration is above 40 ml to about 50 ml/liter.
- 7. A bath as set forth in claim 1 in which the chelating agent is a water soluble phosphonic acid.
- 8. A bath as set forth in claim 1 in which the chelating agent is selected from the group consisting of amino-tri (methylene phosphonic acid) and 1-hydroxyethylidene-1,1-diphosphonic acid.
- 9. A bath as set forth in claim 1 which also contains an alkali metal monophosphate.
- 10. A bath as set forth in which the phosphate is monopotassium phosphate.
- 11. A bath as set forth in claim 1 in which the gold cyanide is potassium gold cyanide.
- 12. A bath as set forth in claim 1 in which the gold metal content is within the range of about 2 g/liter to about 20 g/liter.
- 13. A bath as set forth in claim 12 in which the gold metal content is within the range of about 2 g/liter to about 4.1 g/liter.
Parent Case Info
RELATED APPLICATION
This application is a continuation-in-part of co-pending application Ser. No. 912,171, filed Sept. 25, 1986, now U.S. Pat. No. 4,670,107, which in turn is a continuation of Ser. No. 836,240, filed March 5, 1986.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4591415 |
Whitlaw |
May 1986 |
|
4670107 |
Lochet |
Jun 1987 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2413736 |
Oct 1974 |
DEX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
836240 |
Mar 1986 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
912171 |
Sep 1986 |
|