US3669906A
Expired / Lapsed
US
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Catalyst for purification of exhaust gases from motor vehicles and industrial plants
Assignee: Evonik Operations GmbH
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Filing: 1970-08-19
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Granted: 1972-06-13
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Expires: 1990-08-19
Abstract
Abstract There is provided a catalyst for the purification of exhaust gases from industrial processes and motor vehicles by combustion of oxidizable impurities contained therein to carbon dioxide and water and removal of nitrogen oxide at elevated temperatures in contact with air consisting essentially of a calcined mixture of eta and gamma aluminum oxide and heavy metal oxide compounds the element chromium and at least one other heavy metal selected from the group consisting of nickel or copper with nickel, the quantity of such heavy metal oxide compounds being 55 to 90 weight percent, the molar proportion of the chromium to the other heavy metal being between about 1:0.5 and 1:2.5 calculated as oxides and the majority of the particles of the heavy metal oxide compounds being of a size of from 0.5 to 5 Mu , whereby the heavy metal oxide compounds have been formed by precipitating chromium from a solution of ammonium bichromate with a soluble salt of said other heavy metal or metals, and whereby said calcining of said mixture having been done at 400*-800* C., preferably in an oxygen-containing atmosphere.
Inventors
- 👤 Edgar Koberstein
- 👤 Eduard Lakatos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:36
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/16; B01J23/24; B01J23/26; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/92; B01D53/94; B01D53/944; B01J23/32; B01J23/34; B01J23/70; B01J23/76; B01J23/84; B01J23/85; B01J23/86; B01J23/868; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y10; Y10S; Y10S502/00; Y10S502/506; Y10S502/512
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
52 words
The catalyst of claim 1, in which said catalyst also contains at least one compound of an element of Group II A of the periodic system, the quantity of Group II A element being 0.5 to 10 weight percent of the heavy metal compounds plus group II A element calulated as oxides.
Claim 2
Dependent Claim
23 words
The catalyst composition according to claim 2, wherein said at least one compound of a Group II A element is a barium compound.
Claim 3
Dependent Claim
19 words
The catalyst according to claim 1, wherein the barium is added to the heavy metal oxide compounds by coprecipitation.
Claim 4
Dependent Claim
19 words
The catalyst of claim 1, in which the content of heavy metal oxide compounds is about 70 weight percent.
Claim 5
Dependent Claim
13 words
The catalyst of claim 1, in which the other heavy metal is nickel.
Claim 6
Dependent Claim
14 words
The catalyst of claim 1, in which other heavy metals are nickel and copper.
Claim 7
Dependent Claim
30 words
The catalyst of claim 1, in which the heavy metal oxide compounds have been prepared by precipitating from a solution of ammonium bichromate and nitrate of the other heavy metal.
Claim 8
Dependent Claim
21 words
The catalyst of claim 1, in which the heavy metal oxide component is a mixture of separately coprecipitated heavy metal compounds.
Claim 9
Dependent Claim
21 words
The catalyst according to claim 1, wherein said aluminum oxide is obtained by calcining precipitated aluminum hydrates comprising boehmite and bayerite.
Claim 10
Dependent Claim
40 words
The catalyst of claim 1, which has been prepared by mixing eta and gamma-aluminum oxide, wetted with nitric acid, with the heavy metal oxide compounds, drying the resultant mixture, moulding it and calcining it at temperatures up to 800* C.
Claim 11
Dependent Claim
37 words
The catalyst of claim 1, which has been prepared by mixing aluminum oxide hydrate with the heavy metal oxide compounds, drying the resultant mixture and moulding it and calcining it at a temperature up to 800* C.
Claim 12
Dependent Claim
39 words
A process for preparing the catalyst of claim 1, wherein the heavy metal oxide compounds are prepared by coprecipitation, calcination of the precipitate and subsequent sieving out a powder of a particle size of 0.5 to 5.0 Mu .
Claim 13
Dependent Claim
20 words
A process for preparing the catalyst of claim 1, comprising moulding powdered catalyst in the presence of a pressing agent.
Claim 14
Dependent Claim
24 words
A process for preparing the catalyst of claim 14, wherein the pressing agent is selected from the group consisting of graphite and stearic acid.
Claim 15
Dependent Claim
105 words
A process for preparing the catalyst of claim 1, which comprises the sequential steps of mixing a freshly prepared aluminum hydroxide press cake with calcined powdered oxide of the heavy metals of a particle size mainly from 0.5 to 5 Mu , drying, grinding the dried composition to particle sizes below 100 Mu , treating the ground composition with an acid selected from the groups consisting of mineral acids and aliphatic carboxylic acids, subsequently mixing with a pressing agent, moulding the product, drying at about 120* C., and calcining the dried product at a temperature of at least 800* C. by gradually increasing the temperature.
Claim 16
Dependent Claim
114 words
A process for preparing the catalyst of claim 2, which comprises the sequental steps of mixing a freshly prepared aluminum hydroxide press cake with calcined powdered oxide of the heavy metals of a particle size mainly from 0.5 to 5 Mu , and containing at least one of the elements Be, Mg, Ca, Sr, Ba, drying, grinding the dried composition to particle sizes below 100 Mu , treating the ground composition with an acid selected from the groups consisting of mineral acids and aliphatic carboxylic acids, subsequently mixing with a pressing agent, moulding the product, drying at 120* C. and calcining the dried product by gradually increasing the temperature to at least 800* C.
Claim 17
Dependent Claim
17 words
A process according to claim 17, wherein the acid for treating the ground composition is nitric acid.
Claim 18
Dependent Claim
26 words
A process according to claim 17, wherein the acid for treating the ground composition is selected from lactic acid, acetic acid, citric acid and propionic acid.
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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |