Patent US4036785A successfully refreshed from Google Patents.
US4036785A
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Catalyst for reduction of nitrogen oxides in presence of ammonia
Assignee: Kurashiki Spinning Co Ltd
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Filing: 1976-08-03
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Granted: 1977-07-19
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Expires: 1996-08-03
Abstract
Abstract A catalyst for reduction of nitrogen oxides in the presence of ammonia, which can be advantageously prepared by treating titanium slag with sulfuric acid at an elevated temperature, optionally followed by treatment with an alkali, and decomposing the resulting product while heating at a temperature of about 400° to 700° C and has a high catalytic activity with a long catalytic life and a high resistance to acid substances.
Inventors
- 👤 Masumi Saito
- 👤 Sumio Tani
- 👤 Shigeaki Matsui
- 👤 Shigeaki Kasaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:04
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J; B01J23/00; B01J23/70; B01J23/74; B01J23/745
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
64 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag having an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag with sulfuric acid at a temperature not lower than about 100° C., drying and calcining the resultant product.
Claim 2
Dependent Claim
64 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag having an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag with sulfuric acid at a temperature not lower than about 100° C., drying and calcining the resultant product.
Claim 3
Dependent Claim
27 words
The process according to claim 1 wherein the titanium slag has a titanium content of about 65 to 95% by weight in terms of TiO 2 .
Claim 4
Dependent Claim
34 words
The process according to claim 1 wherein the molar ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 is not less than 1.2:1.
Claim 5
Dependent Claim
24 words
The process according to claim 1 wherein the treatment with sulfuric acid is carried out at a temperature of about 120° to 160° C.
Claim 6
Dependent Claim
21 words
The process according to claim 1 wherein the calcining is carried out at a temperature of about 400° to 700° C.
Claim 7
Dependent Claim
17 words
The process according to claim 1 where the resultant product is treated with an alkali before calcining.
Claim 8
Dependent Claim
27 words
The process according to claim 6 wherein the titanium slag has a titanium content of about 65 to 95% by weight in terms of TiO 2 .
Claim 9
Dependent Claim
34 words
The process according to claim 6 wherein the molar ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 is not less than 1.2:1.
Claim 10
Dependent Claim
24 words
The process according to claim 6 wherein the treatment with sulfuric acid is carried out at a temperature of about 120° to 160° C.
Claim 11
Dependent Claim
21 words
The process according to claim 6 wherein the calcining is carried out at a temperature of about 400° to 700° C.
Claim 12
Dependent Claim
120 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., filtering the resultant mixture, treating the resultant filtrate with alkali to form a precipitate, drying and calcining the precipitate.
Claim 13
Dependent Claim
120 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., filtering the resultant mixture, treating the resultant filtrate with alkali to form a precipitate, drying and calcining the precipitate.
Claim 14
Dependent Claim
117 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., filtering the resultant mixture, neutralizing the resultant precipitate with alkali, drying and calcining the resultant product.
Claim 15
Dependent Claim
117 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., filtering the resultant mixture, neutralizing the resultant precipitate with alkali, drying and calcining the resultant product.
Claim 16
Dependent Claim
117 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., treating the resultant mixture with alkali to form a precipitate, collecting, drying and calcining the precipitate.
Claim 17
Dependent Claim
117 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia which comprises treating titanium slag, having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag, with sulfuric acid, the mole ratio of sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature not lower than about 100° C., treating the resultant mixture with alkali to form a precipitate, collecting, drying and calcining the precipitate.
Claim 18
Dependent Claim
131 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia, which comprises heating a mixture of titanium slag with about 50 to 90% (w/w) sulfuric acid in a molar ratio of the sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature of about 120° to 160° C., drying and decomposing the resulting product while heating at a temperature of about 400° to 700° C., the titanium slag having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag.
Claim 19
Dependent Claim
131 words
A process for preparing a catalyst for reduction of nitrogen oxides in the presence of ammonia, which comprises heating a mixture of titanium slag with about 50 to 90% (w/w) sulfuric acid in a molar ratio of the sulfuric acid in terms of H 2 SO 4 and the titanium slag in terms of TiO 2 being not less than 1.2:1, at a temperature of about 120° to 160° C., drying and decomposing the resulting product while heating at a temperature of about 400° to 700° C., the titanium slag having a titanium content of about 65 to 95% by weight in terms of TiO 2 and an iron content of about 2 to 8% by weight in terms of FeO on the basis of the weight of the titanium slag.
Claim 20
Dependent Claim
17 words
The process according to claim 14 wherein said resultant product is neutralized with an alkali before decomposition.
Claim 21
Dependent Claim
11 words
A catalyst prepared by the process as claimed in claim 1.
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) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |