US4130625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery and purification of iridium
Assignee: National Institute of Metallurgy
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Filing: 1977-06-15
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Granted: 1978-12-19
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Expires: 1997-06-15
Abstract
Abstract A method of recovering iridium from a solution thereof containing rhodium and impurities in the form of base metals comprising; oxidizing the iridium to the Ir(IV) oxidation state in an acid solution in the presence of chloride ions; removing the iridium chlorocomplexes formed using a suitable anion-exchange resin; washing the resin; treating the iridium with an aqueous solution of sulphur dioxide which is substantially free of chloride ions; and thereafter eluting the iridium complex formed from the resin using a suitable eluant.
Inventors
- 👤 Ann P. Evers
- 👤 Roderick I. Edwards
- 👤 Monika M. Fieberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:33
CPC Classifications
C; C01; C01G; C01G55/00; C01G55/001; C22; C22B; C22B11/00; C22B11/04; C22B3/00; C22B3/20; C22B3/42; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
164 words
A method of separating iridium from a solution thereof also containing rhodium the method comprising the steps of: (1) oxidizing the solution in the presence of hydrochloric acid to convert the iridium contained therein to the Ir(IV) oxidation state; (2) passing the solution into contact with an anion exchange resin to retain the oxidized iridium on the resin; (3) washing the resin with a dilute hydrochloric acid solution to remove any solution entrained therein; (4) contacting the washed resin with a substantially chloride free solution of sulphur dioxide in water thereby reducing the iridium to the Ir(111) oxidation state and simultaneously forming iridium sulphito-chloro-complexes; (5) eluting the resin with a hydrochloric acid solution to remove the iridium sulphito-chloro complexes therefrom; (6) boiling the resultant solution containing the iridium sulphito-chloro complexes to convert the iridium to the chloro-complex with the iridium in the Ir(III) oxidation state and to simultaneously remove sulphur dioxide; and (7) recovering the iridium from the solution resulting from step (6) above.
Claim 2
Independent Claim
164 words
A method of separating iridium from a solution thereof also containing rhodium the method comprising the steps of: (1) oxidizing the solution in the presence of hydrochloric acid to convert the iridium contained therein to the Ir(IV) oxidation state; (2) passing the solution into contact with an anion exchange resin to retain the oxidized iridium on the resin; (3) washing the resin with a dilute hydrochloric acid solution to remove any solution entrained therein; (4) contacting the washed resin with a substantially chloride free solution of sulphur dioxide in water thereby reducing the iridium to the Ir(111) oxidation state and simultaneously forming iridium sulphito-chloro-complexes; (5) eluting the resin with a hydrochloric acid solution to remove the iridium sulphito-chloro complexes therefrom; (6) boiling the resultant solution containing the iridium sulphito-chloro complexes to convert the iridium to the chloro-complex with the iridium in the Ir(III) oxidation state and to simultaneously remove sulphur dioxide; and (7) recovering the iridium from the solution resulting from step (6) above.
Claim 3
Dependent Claim
22 words
A method as claimed in claim 1 in which step (1) is conducted in the presence of about 6 molar hydrochloric acid.
Claim 4
Dependent Claim
27 words
A method as claimed in claim 1 in which step (1) is conducted at a temperature of at least about 40° C. using chlorine as the oxidant.
Claim 5
Dependent Claim
20 words
A method as claimed in claim 1 in which the anion exchange resin is a strongly basic anion exchange resin.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 1 wherein the dilute hydrochloric acid of step (3) has a concentration of about 0.1 molar HCl.
Claim 7
Dependent Claim
22 words
A method as claimed in claim 1 in which a saturated solution of sulphur dioxide in water is used in step (4).
Claim 8
Dependent Claim
25 words
A method as claimed in claim 1 in which the elution of step (5) is conducted using a hydrochloric acid solution of about 6 molar.
Claim 9
Dependent Claim
82 words
A method as claimed in claim 1 in which the iridium is recovered including steps of: (8) oxidizing the iridium contained in the solution resulting from step (6) in the presence of hydrochloric acid converting iridium to the Ir(IV) oxidation state; (9) contacting the resultant solution with an organic phase containing a liquid solvent extractant and extracting the iridium into the organic phase; and, (10) stripping the organic phase with a dilute hydrochloric acid solution removing iridium from the resulting aqueous phase.
Claim 10
Dependent Claim
16 words
A method as claimed in claim 9 in which the liquid solvent extractant is tri-butyl phosphate.
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) | 1981-12-18 | 1982-06-19 | 1982-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-18 | 1986-06-19 | 1986-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-18 | 1990-06-19 | 1990-12-19 | $7700.00 | Window Closed / Lapsed |