US4511539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of precious metal
Assignee: Johnson Matthey PLC
•
Filing: 1984-03-19
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Granted: 1985-04-16
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Expires: 2004-03-19
Abstract
Abstract The invention relates to the recovery of precious metal lost from precious metal-containing catalysts for example the precious metal-containing catalysts which are used in the production of nitric acid by ammonia oxidation. In more detail, a getter (as herein defined) for recovery of precious metal lost from a precious metal-containing catalyst operating at elevated temperature comprises an agglomeration or assemblage of unwoven fibres made from a metal selected from the group ruthenium, palladium, iridium, platinum, gold, silver, rhodium and alloys containing one or more of the said metals. Preferably, the unwoven fibres are randomly oriented.
Inventors
- 👤 David J. Stephenson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:20
CPC Classifications
C; C22; C22B; C22B7/00; C22B7/009; C22B11/00; C22B11/02; C22B11/021; C22B11/026; C22B11/028; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
87 words
A getter for recovery of precious metal lost from a precious metal-containing catalyst operating at elevated temperature which comprises a self-supporting or supported agglomeration or assemblage of unwoven, randomly oriented fibres of a length falling within the range of 1/2 to 4 inches, an irregular surface and made from a precious metal selected from the group consisting of ruthenium, rhodium, palladium, iridium, platinum, gold, silver and alloys containing one or more of the said metals, said fibres being produced by a melt extraction or melt spun process.
Claim 2
Dependent Claim
87 words
A getter for recovery of precious metal lost from a precious metal-containing catalyst operating at elevated temperature which comprises a self-supporting or supported agglomeration or assemblage of unwoven, randomly oriented fibres of a length falling within the range of 1/2 to 4 inches, an irregular surface and made from a precious metal selected from the group consisting of ruthenium, rhodium, palladium, iridium, platinum, gold, silver and alloys containing one or more of the said metals, said fibres being produced by a melt extraction or melt spun process.
Claim 3
Dependent Claim
22 words
A getter according to claim 1 wherein the fibres are of generally circular or non-circular cross section and bearing an irregular surface.
Claim 4
Dependent Claim
21 words
A getter according to claim 1 wherein the length of the fibres falls within the range of 1/2 to 2 inches.
Claim 5
Dependent Claim
40 words
A getter according to claim 3 wherein the fibres are of "D"-cross-sectional shape having the major dimension thereof falling within the range 0.004 to 0.006 inch and having the minor dimension thereof falling within the range 0.002 to 0.005 inch.
Claim 6
Dependent Claim
11 words
A getter according to claim 1 wherein the fibres are crimped.
Claim 7
Dependent Claim
31 words
A getter according to claim 1 wherein the agglomeration of fibres is compressed to a density such that the agglomeration contains between 10 and 30 kg per square meter of agglomerate.
Claim 8
Dependent Claim
24 words
A getter according to claim 6 wherein the said density falls within the range of 15 to 20 kg per square meter of agglomerate.
Claim 9
Dependent Claim
32 words
A getter according to claim 1 wherein the agglomeration of fibres is supported on at least one support gauze made from a platinum group metal or alloy thereof, stainless steel or Kanthal.
Claim 10
Dependent Claim
35 words
A getter according to claim 1 wherein the agglomeration of fibres is sandwiched between layers comprising one or more gauzes made from a platinum group metal, or alloy thereof or a stainless steel or Kanthal.
Claim 11
Dependent Claim
46 words
A getter according to claim 1 including a first agglomeration of fibres sandwiched between first and second layers comprising at least one support gauze and a second agglomeration of fibres sandwiched between the said second layer and a third layer comprising at least one support gauze.
Claim 12
Dependent Claim
28 words
A getter according to claim 10 including a third agglomeration of fibres sandwiched between the said third layer and a fourth layer comprising at least one support gauze.
Claim 13
Dependent Claim
14 words
A getter according to claim 10 wherein the said first layer comprises a catalyst.
Claim 14
Dependent Claim
23 words
A getter according to claim 1 wherein the total weight of the fibres constitutes up to 50% of the weight of the catalyst.
Claim 15
Dependent Claim
43 words
A getter according to claim 11 wherein the fibres of the first agglomeration constitute up to 50% of the total weight of the fibres and each of the second and third agglomerates constitute up to 25% of the total weight of the fibres.
Claim 16
Dependent Claim
24 words
A getter according to claim 13 wherein the total weight of the fibres constitutes from 1 to 10% of the weight of the catalyst.
Claim 17
Dependent Claim
15 words
A getter according to claim 1 wherein the fibres are made from a gold-palladium alloy.
Claim 18
Dependent Claim
13 words
A getter according to claim 1 wherein the fibres are made from palladium.
Claim 19
Dependent Claim
20 words
A getter according to claim 12 wherein the catalyst comprises 90 wt% platinum, 5 wt% rhodium and 5 wt% gold.
Claim 20
Dependent Claim
17 words
A getter according to claim 12 wherein the catalyst comprises 90 wt% platinum and 10 wt% rhodium.
Claim 21
Dependent Claim
14 words
A getter according to claim 15 which comprises a palladium-gold alloy contains 5% gold.
Claim 22
Dependent Claim
21 words
A getter according to claim 16 which comprises a palladium-gold alloy in which the palladium-gold alloy contains less than 15% gold.
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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) | 1988-04-15 | 1988-10-15 | 1989-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-15 | 1992-10-15 | 1993-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-15 | 1996-10-15 | 1997-04-16 | $7700.00 | Window Closed / Lapsed |