US3979207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refining of noble group metals
Assignee: Matthey Rustenburg Refiners Pty Ltd
•
Filing: 1974-12-10
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Granted: 1976-09-07
•
Expires: 1994-12-10
Abstract
Abstract This invention relates to the separation and purification of platinum group metals and, in particular to the separation of mixtures of rhodium, platinum and irridium. According to one specific form of the invention, the platinum, rhodium and iridium are present as salts in aqueous solution and the separation and purification is accomplished by A. adjusting the pH, as necessary, to provide an acidic solution; B. contacting the acidic solution with an oxidizing agent sufficient to effect the oxidation of all irridium to Ir(IV); c. contacting the oxidized solution with a nitrogen-containing organic compound selected from the group consisting of secondary amines, tertiary amines and quaternary ammonium compounds; and D. removing from contact with the oxidized solution an organic phase containing substantially all of the platinum and iridium present in association with the nitrogen-containing organic compound used in step (c).
Inventors
- 👤 John James MacGregor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:03
CPC Classifications
C; C01; C01G; C01G55/00; C01G55/001; C22; C22B; C22B11/00; C22B11/04; C22B3/00; C22B3/20; C22B3/26; C22B3/262; C22B3/28; C22B3/282; C22B3/288; C22B3/306; C22B3/32; C22B3/322; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
152 words
A process for the separation and purification of platinum, rhodium and iridium present as salts in an aqueous solution which cmprises the steps of: a. adjusting the pH, as necessary, to provide an acidic solution; b. contacting the acidic solution with an oxidising agent sufficient to effect the oxidation of all iridium to Ir(IV); c. contacting the oxidised solution with a tertiary amine of the general formula R 3 N where R is alkyl of from 6-12 carbon atoms; d. removing from contact with the oxidised solution an organic phase containing substantially all of the platinum and iridium present in association with the nitrogen-containing organic compound used in step (c); e. removing the iridium from the organic phase by contacting with an aqueous solution of a reducing agent leaving substantially all of the platinum in the organic phase; and f. removing the platinum from the organic phase with an aqueous stripping solution.
Claim 2
Dependent Claim
152 words
A process for the separation and purification of platinum, rhodium and iridium present as salts in an aqueous solution which cmprises the steps of: a. adjusting the pH, as necessary, to provide an acidic solution; b. contacting the acidic solution with an oxidising agent sufficient to effect the oxidation of all iridium to Ir(IV); c. contacting the oxidised solution with a tertiary amine of the general formula R 3 N where R is alkyl of from 6-12 carbon atoms; d. removing from contact with the oxidised solution an organic phase containing substantially all of the platinum and iridium present in association with the nitrogen-containing organic compound used in step (c); e. removing the iridium from the organic phase by contacting with an aqueous solution of a reducing agent leaving substantially all of the platinum in the organic phase; and f. removing the platinum from the organic phase with an aqueous stripping solution.
Claim 3
Dependent Claim
24 words
A process according to claim 1 in which the amine at step (c) is equilibrated with an acid before contacting with the acidified solution.
Claim 4
Dependent Claim
13 words
A process according to claim 2 in which the acid is hydrochloric acid.
Claim 5
Dependent Claim
29 words
A process according to claim 1 in which the alkyl group is selected from the group comprising normal and iso hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl groups.
Claim 6
Dependent Claim
28 words
A process according to claim 4 in which the tertiary amine is selected from the group consisting of tri-n-hexylamine, methyl di-n-octylamine, tri-n-octylamine, tri-iso-octylamine, tri-n-heptylamine, tri-iso-heptylamine, tri-n-nonylamine and tri-iso-nonylamine.
Claim 7
Dependent Claim
27 words
A process according to claim 1 in which the aqueous solution at step (a) is acidified to establish a hydrochloric acid strength within the range 3-9 molar.
Claim 8
Dependent Claim
35 words
A process according to claim 1 in which the reducing agent at step (e) is selected from the group consisting of sulphite, a carboxylate, sulphur dioxide, hydrazine, a ketone, an aldehyde, an alcohol and hydrogen.
Claim 9
Dependent Claim
20 words
A process according to claim 7 in which the carboxylate is selected from the group consisting of oxalate and formate.
Claim 10
Dependent Claim
12 words
A process according to claim 7 in which the ketone is acetone.
Claim 11
Dependent Claim
12 words
A process according to claim 7 in which the aldehyde is formaldehyde.
Claim 12
Dependent Claim
12 words
A process according to claim 7 in which the alcohol is ethanol.
Claim 13
Dependent Claim
22 words
A process according to claim 1 in which the organic phase is stripped of its platinum at step (f) with an acid.
Claim 14
Dependent Claim
32 words
A process according to claim 12 in which the acid is a strong aqueous solution of an acid selected from the group comprising hydrochloric acid, sulphuric acid, nitric acid and perchloric acid.
Claim 15
Dependent Claim
31 words
A process according to claim 12, in which the stripped platinum is reduced to the pure metal by a reducing agent selected from the group comprising hydrazine and hydrogen under pressure.
Claim 16
Dependent Claim
22 words
A process according to claim 1 in which the organic phase is stripped of its platinum at step (f) with an alkali.
Claim 17
Dependent Claim
38 words
A process according to claim 15 in which the alkali is an aqueous solution of one selected from the group comprising lithium hydroxide, potassium hydroxide, sodium hydroxide, ammonium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate.
Claim 18
Dependent Claim
20 words
A process according to claim 15 in which the alkali is an aqueous solution within the range 5-20% by weight.
Claim 19
Dependent Claim
37 words
A process according to claim 1 in which the oxidising agent used at step (b) is selected from the group consisting of gaseous chlorine, hypochlorite, gaseous bromine, hypobromite, chlorate, bromate, iodate, hydrogen peroxide and cerium (IV) ions.
Claim 20
Dependent Claim
39 words
A process according to claim 1 in which the organic phase removed at stage (d) is stripped of its platinum and iridium by contact with an aqueous solution containing a reagent selected from the group comprising acids and alkalis.
Claim 21
Dependent Claim
32 words
A process according to claim 19 in which the acid is an aqueous solution of a strong acid selected from the group comprising hydrochloric acid, nitric acid, sulphuric acid and perchloric acid.
Claim 22
Dependent Claim
33 words
A process according to claim 19 in which the alkali is selected from the group comprising lithium hydroxide, potassium hydroxide, sodium hydroxide, ammonium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate.
Claim 23
Dependent Claim
20 words
A process according to claim 21 in which the alkali is an aqueous solution within the range 5-20% by weight.
Claim 24
Dependent Claim
29 words
A process according to claim 19 in which the alkali is used as the stripping agent and the precipitated hydrated oxide of iridium is re-dissolved in acid and reduced.
Claim 25
Dependent Claim
23 words
A process according to claim 23 in which the dissolved platinum is re-extracted with a secondary or tertiary amine or quaternary ammonium compound.
Claim 26
Dependent Claim
23 words
A process according to claim 23 in which the dissolved iridium is recovered by precipitation as (NH 4 ) 2 IrCl 6 .
Claim 27
Dependent Claim
22 words
A process according to claim 25 in which (NH 4 ) 2 IrCl 6 is ignited and reduced to the pure metal.
Claim 28
Dependent Claim
15 words
A process according to claim 26 in which the reduction is carried out by hydrogen.
Claim 29
Dependent Claim
30 words
A process according to claim 1 in which the organic phase removed at stage (d) is stripped of its iridium by contact with an aqueous solution of a reducing agent.
Claim 30
Dependent Claim
27 words
A process according to claim 28 in which the reducing agent is selected from the group comprising sulphite, bisulphite, hyposulphite, metabisulphite, thiosulphate and dissolved SO 2 .
Claim 31
Dependent Claim
31 words
A process according to claim 1 in which the rhodium present in the aqueous solution remaining after removal of the organic phase at step (d) is purified by precipitation and recrystallisation.
Claim 32
Dependent Claim
20 words
A process according to claim 30 in which the rhodium is precipitated as Na 3 RhCl 6 12H 2 O.
Claim 33
Dependent Claim
29 words
A process according to claim 31 in which rhodium metal is obtained by reduction of an aqueous solution of Na 3 RhCl 6 with hydrazine or hydrogen under pressure.
Claim 34
Dependent Claim
37 words
A process according to claim 1 in which the rhodium present in the aqueous solution remaining after the removal of the organic phase at step (d) is reduced to rhodium metal by hydrazine or hydrogen under pressure.
Claim 35
Dependent Claim
16 words
A process according to claim 1 when carried out in a multi-stage counter-current solvent extraction apparatus.
Claim 36
Dependent Claim
138 words
A process for the separation of salts of platinum, rhodium and iridium in aqueous solution which comprises the steps of: a. acidifying the solution; b. contacting the acidified solution with an oxidising agent sufficient to oxidise all of the iridium present to Ir(IV); c. contacting the solution with a tertiary amine R 3 N equilibrated with hydrochloric acid in which R is C 8 -C 10 alkyl with normal C 8 predominating; d. removing from contact with the solution the organic phase containing substantially all of the platinum and iridium present in association with the said tertiary amine, e. removing the iridium from the organic phase by contacting with an aqueous solution of a reducing agent leaving substantially all the platinum in the organic phase, and f. removing the platinum from the organic phase with alkaline strip liquor.
Claim 37
Dependent Claim
138 words
A process for the separation of salts of platinum, rhodium and iridium in aqueous solution which comprises the steps of: a. acidifying the solution; b. contacting the acidified solution with an oxidising agent sufficient to oxidise all of the iridium present to Ir(IV); c. contacting the solution with a tertiary amine R 3 N equilibrated with hydrochloric acid in which R is C 8 -C 10 alkyl with normal C 8 predominating; d. removing from contact with the solution the organic phase containing substantially all of the platinum and iridium present in association with the said tertiary amine, e. removing the iridium from the organic phase by contacting with an aqueous solution of a reducing agent leaving substantially all the platinum in the organic phase, and f. removing the platinum from the organic phase with alkaline strip liquor.
References Cited (Backward Citations)
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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) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |