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Patent US4025604A successfully refreshed from Google Patents.
US4025604A
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US
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Method of removing nitrogen oxides from exhaust gas by reduction
Assignee: JFE Engineering Corp
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Filing: 1974-12-16
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Granted: 1977-05-24
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Expires: 1994-12-16
Abstract
Abstract Powder and/or fine particles containing mainly oxides of iron or ferroalloys, which are used or generated in ironworks, steelworks, etc. are sieved to a grain size range between about 32 mesh and about 10mm and used as reduction catalyzer. A reactor is filled with said reduction catalyzer. Exhaust gas containing nitrogen oxides and with added ammonia is passed in contact with said reduction catalyzer through said reactor, while heating said reduction catalyzer to a temperature between about 300 DEG C and about 370 DEG C, whereby nitrogen oxides are removed from said exhaust gas by reduction. Said reduction catalyzer can be used as material for ironmaking, without requiring any further treatment, after use as catalyzer.
Inventors
- 👤 Sanseki Moriguchi
- 👤 Hiroshi Abe
- 👤 Taisuke Nishida
- 👤 Jyoichi Takenaka
- 👤 Makoto Miyazawa
- 👤 Sadayoshi Iwabuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:37
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/70; B01J23/76; B01J23/84; B01J23/889; B01J23/8892; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
96 words
A method of removing a nitrogen oxide from an exhaust gas by reduction in the presence of ammonia and a catalyst, which comprises: contacting, at a temperature of from about 300° C. to about 370° C., the exhaust gas and ammonia with an iron-oxide-containing catalyst having a grain size between about 32 mesh and about 10 mm, said catalyst being unsupported and uncompressed and being selected from the group consisting of magnetically separated blast furnace dust, iron ore, sintering plant dust, dust obtained from a top-blowing oxygen converter device, Si-Mn-Fe ferroalloy scale, and Mn-Fe ferroalloy scale.
Claim 2
Independent Claim
96 words
A method of removing a nitrogen oxide from an exhaust gas by reduction in the presence of ammonia and a catalyst, which comprises: contacting, at a temperature of from about 300° C. to about 370° C., the exhaust gas and ammonia with an iron-oxide-containing catalyst having a grain size between about 32 mesh and about 10 mm, said catalyst being unsupported and uncompressed and being selected from the group consisting of magnetically separated blast furnace dust, iron ore, sintering plant dust, dust obtained from a top-blowing oxygen converter device, Si-Mn-Fe ferroalloy scale, and Mn-Fe ferroalloy scale.
Claim 3
Dependent Claim
14 words
The method of claim 1, wherein the catalyst is magnetically separated blast furnace dust.
Claim 4
Dependent Claim
11 words
The method of claim 1, wherein the catalyst is iron ore.
Claim 5
Dependent Claim
12 words
The method of claim 1, wherein the catalyst is sintering plant dust.
Claim 6
Dependent Claim
16 words
The method of claim 1, wherein the catalyst is dust obtained from a top-blowing oxygen converter.
Claim 7
Dependent Claim
12 words
The method of claim 1, wherein the catalyst is Si-Mn-Fe ferroalloy scale.
Claim 8
Dependent Claim
12 words
The method of claim 1, wherein the catalyst is Mn-Fe ferroalloy scale.
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) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |