US4069040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for recovery of platinum and iridium from catalysts
Assignee: Rhone Poulenc Industries SA
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Filing: 1974-11-18
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Granted: 1978-01-17
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Expires: 1994-11-18
Abstract
Abstract The invention relates to the recovery of the constituent elements of catalysts containing precious metals, such as platinum and iridium deposited on aluminous supports. This recovery is accomplished by a substantially total solubilization of the catalysts by means of hydrochloric acid and by extraction, for example by means of ion exchange resins. This system allows for a good separation of the platinum and the iridium.
Inventors
- 👤 Maryvonne Thomas
- 👤 Jean Grosbois
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:03
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; C01; C01G; C01G55/00; C01G55/001; C22B11/042; C22B11/048; C22B3/00; C22B3/20; C22B3/26; C22B3/32; C22B3/322; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
116 words
A method for the recovery of constituents of catalysts containing platinum and iridium on an aluminous support, comprising the steps of a. attacking the catalyst with a 3-9 M hydrochloric acid solution to dissolve alumina, platinum and iridium, b. adding to the solution a sufficient quantity of reducing agent to convert dissolved iridium to the trivalent state, c. passing the solution into contact with an anion exchange medium on which platinum becomes strongly fixed leaving alumina and iridium in solution, d. adding an oxidizing agent to the solution from (c) to convert trivalent iridium to the tetravalent state, e. passing the solution into contact with an anion exchange medium on which the iridium becomes strongly fixed.
Claim 2
Independent Claim
116 words
A method for the recovery of constituents of catalysts containing platinum and iridium on an aluminous support, comprising the steps of a. attacking the catalyst with a 3-9 M hydrochloric acid solution to dissolve alumina, platinum and iridium, b. adding to the solution a sufficient quantity of reducing agent to convert dissolved iridium to the trivalent state, c. passing the solution into contact with an anion exchange medium on which platinum becomes strongly fixed leaving alumina and iridium in solution, d. adding an oxidizing agent to the solution from (c) to convert trivalent iridium to the tetravalent state, e. passing the solution into contact with an anion exchange medium on which the iridium becomes strongly fixed.
Claim 3
Dependent Claim
25 words
The method as claimed in claim 1 in which the attack on the catalyst is carried out under reflux at a temperature above 80° C.
Claim 4
Dependent Claim
25 words
The method as claimed in claim 1 in which the hydrochloric acid solution is employed at a rate of 6-20 liters per kilogram of catalyst.
Claim 5
Dependent Claim
22 words
The method as claimed in claim 1 in which the catalyst is attacked with a hydrochloric acid solution containing an oxidizing agent.
Claim 6
Dependent Claim
28 words
The method as claimed in claim 4 in which the oxidizing agent is selected from the group consisting of chlorine, chlorate, chlorite and hydrogen peroxide in aqueous solution.
Claim 7
Dependent Claim
27 words
The method as claimed in claim 4 in which the oxidizing agent is nitric acid in a range of 7 to 5 ml. per l of solution.
Claim 8
Dependent Claim
26 words
The method as claimed in claim 1 in which the reducing agent is selected from the group consisting of sulfites, nitrites, oxalic acid and formic acid.
Claim 9
Dependent Claim
25 words
The method as claimed in claim 1 in which the solution is heated for a period of time after the addition of the reducing agent.
Claim 10
Dependent Claim
49 words
The method as claimed in claim 1 in which the oxidizing agent added to the solution from the first ion exchange to convert iridium from the trivalent to the tetravalent state is selected from the group consisting of nitric acid, chlorine, chlorites, chlorates and hydrogen peroxide in aqueous solution.
Claim 11
Dependent Claim
23 words
The method as claimed in claim 1 in which the ion exchange medium in steps (c) and (e) is an anion exchange resin.
Claim 12
Dependent Claim
24 words
The method as claimed in claim 10 which includes a step of calcining the anion exchange resin from step (c) to recover the platinum.
Claim 13
Dependent Claim
24 words
The method as claimed in claim 10 which includes the step of calcining the anion exchange resin from step (e) to recover the iridium.
References Cited (Backward Citations)
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US3725047A
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US3728103A
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US3672874A
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US3787554A
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US3999983A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |