Claims
- 1. In the process of electrowinning a metal from an aqueous solution of a sulphate thereof, the improvement of using as oxygen evolving anode an activated catalytic antimony-free lead base anode having improved oxygen overvoltage prepared by contacting the antimony-free lead base with a molten bath of at least one hydrated salt belonging to the group of nitrates and persalts of a member selected from the group of cobalt, iron, and nickel at a temperature lower than the melting temperature of said antimony-free lead base and for a time sufficient to activate the surface and obtain said activated catalytic lead base anode and wherein said lead base exhibits improved oxygen overvoltage as a consequence of the process by which it was prepared.
- 2. The process of claim 1 wherein said time is between 20 minutes and 3 hours.
- 3. The process of claim 1 wherein said time is between 1 and 3 hours and said temperature is 90.degree.-100.degree. C.
- 4. The process of claim 1 wherein said time is about 20 to 30 minutes and said temerature is 150.degree.-200.degree. C.
- 5. The process of claim 1 wherein said improved oxygen overvoltage results in a reduction in anodic potential between 0.15 and 0.25 volts as compared to anode not subjected to said process.
- 6. The process of claim 1 wherein said base is lead.
- 7. The process of claim 1 wherein said lead base is an alloy of lead and 0.5-1.5% silver.
- 8. The process of claim 1 wherein said lead base is an alloy of lead and 0.5-1% calcium.
- 9. The process of claim 1 wherein the molten bath is of hydrated cobalt nitrate.
- 10. The process of claim 1 wherein the presalts are members of the group of acid persulphates, percabonates, perborates, and perphosphates.
- 11. The process of claim 1 wherein the lead base is an alloy of lead and silver.
- 12. The process of claim 1 wherein the lead base is an alloy of lead and calcium.
Priority Claims (1)
Number |
Date |
Country |
Kind |
19565 A/83 |
Feb 1983 |
ITX |
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Parent Case Info
This is a division, of application Ser. No. 568,766, filed 1/6/84, now U.S. Pat. No. 4,548,697.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
3616323 |
Covitz |
Oct 1971 |
|
4142005 |
Caldwell et al. |
Feb 1979 |
|
4345987 |
Fukasawa et al. |
Aug 1982 |
|
4459189 |
Vance et al. |
Jul 1984 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
328198 |
Mar 1972 |
SUX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
568766 |
Jan 1984 |
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