Claims
- 1. A process for the electrolytic recovery of metals from solutions containing metal ions and fluorides or anionic fluorocomplexes carried out in diaphragmless cells, said process comprising the steps of metal deposition from said metal ions and oxygen evolution characterized in that the said oxygen evolution takes place at ceramic insoluble anodes which resist the aggressive action of said solutions, said anodes being made of sinterized powders of tin dioxide doped with copper oxide and antimony oxide or copper oxide and chromium oxide or copper oxide and praseodymium oxide.
- 2. The process of claim 1 wherein the ratio by weight of said copper oxide and antimony oxide is 1% and 1 to 3% respectively.
- 3. The process of claim 1 wherein said metal ions are selected from the group consisting of lead, tin and chromium ions.
- 4. The process of claim 1 wherein the said solutions further contain zirconyl phosphate to prevent the deposition of high-valence oxides of said metal ions onto the anode surface.
- 5. The process of claim 4 wherein the concentration of zirconyl phosphate in said solutions is between 500 and 3,000 parts per million.
- 6. The process of claim 1 wherein said solutions further contain ionic couples selected from the group consisting of Ce.sup.III /Ce.sup.IV and Pr.sup.III /Pr.sup.IV to catalyze the oxygen evolution reaction.
- 7. The process of claim 1 wherein said anodes comprise a layer of zirconyl phosphate.
- 8. The process of claim 7 wherein the thickness of said layer of zirconyl phosphate is 10 to 250 microns.
- 9. The process of claim 1 wherein said anodes further comprise a coating to catalyze the oxygen evolution reaction, said coating being based on oxides of metals selected from the group consisting of cerium, praseodymium, manganese and combinations thereof, further doped by oxides of the elements selected from the group consisting of niobium, copper, nickel and chromium.
Priority Claims (3)
Number |
Date |
Country |
Kind |
91000479 |
Feb 1991 |
ITX |
|
91000514 |
Feb 1991 |
ITX |
|
91000550 |
Mar 1991 |
ITX |
|
DESCRIPTION OF THE INVENTION
This is continuation of Ser. No. 08/025,969, filed Mar. 3, 1993, now abandoned, which is divisional of Ser. No. 07/839,114, filed Feb. 20, 1992, now abandoned.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
3772168 |
Dillenberg |
Nov 1973 |
|
4146438 |
De Nora et al. |
Mar 1979 |
|
4720334 |
DuBois et al. |
Jan 1988 |
|
5207877 |
Weinberg et al. |
May 1993 |
|
Non-Patent Literature Citations (1)
Entry |
Hibbert et al., Dictionary of Electrochemistry, "Electroplating", Second Edition, p. 127, 1984. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
839114 |
Feb 1992 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
25969 |
Mar 1993 |
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