US4010239A
Expired / Lapsed
US
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Iron oxide sorbents for sulfur oxides
Assignee: HR LAB Corp A DE CORP
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Filing: 1973-10-05
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Granted: 1977-03-01
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Expires: 1993-10-05
Abstract
Abstract A highly sorbent iron oxide is prepared by reducing hematite to magnetite followed by a low temperature oxidation prior to contact with sulfur dioxide. The oxidized solids obtained in this manner are a more effective form of iron oxide sorbent for the oxides of sulfur.
Inventors
- 👤 Abraham A. Dor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:00
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/60
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
115 words
In a process for removing sulfur oxides from a gas containing sulfur oxides and oxygen by contacting said gas with an iron oxide sorbent in an absorption zone at a temperature of from about 250° to about 700° C. to form iron sulfate-bearing solids and a gas reduced in sulfur oxide content, the improvement comprising the use of an iron oxide prepared by the process comprising the steps of a. providing a quantity of hematite, b. heating the hematite in the presence of reducing agents at a temperature below about 1000° C. to produce magnetite-bearing solids, and c. oxidizing said magnetite-bearing solids at a temperature below about 600° C. to produce an iron oxide-bearing sorbent.
Claim 2
Dependent Claim
115 words
In a process for removing sulfur oxides from a gas containing sulfur oxides and oxygen by contacting said gas with an iron oxide sorbent in an absorption zone at a temperature of from about 250° to about 700° C. to form iron sulfate-bearing solids and a gas reduced in sulfur oxide content, the improvement comprising the use of an iron oxide prepared by the process comprising the steps of a. providing a quantity of hematite, b. heating the hematite in the presence of reducing agents at a temperature below about 1000° C. to produce magnetite-bearing solids, and c. oxidizing said magnetite-bearing solids at a temperature below about 600° C. to produce an iron oxide-bearing sorbent.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein the oxidation of the magnetite-bearing solid occurs in the absorption zone.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein the hematite of step (a) is a natural hematite.
Claim 5
Dependent Claim
21 words
The process of claim 1 wherein the hematite of step (a) is a synthetic hematite obtained by the oxidation of magnetite.
Claim 6
Dependent Claim
18 words
The process of claim 1 wherein the magnetite-bearing solids are oxidized at a temperature below about 450° C.
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) | 1980-02-29 | 1980-08-30 | 1981-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-29 | 1984-08-30 | 1985-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-29 | 1988-08-30 | 1989-03-01 | $7700.00 | Window Closed / Lapsed |