US3985860A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for oxidation of SO2 scrubber sludge
Assignee: MW Kellogg Co
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Filing: 1975-09-22
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Granted: 1976-10-12
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Expires: 1995-09-22
Abstract
Abstract This process provides for the oxidation of calcium sulfite produced from wet scrubbing sulfur oxides to gypsum in an aqueous medium containing magnesium sulfate. The process renders scrubber sludge filterable for further manufacturing use or disposal without use of acidic streams.
Inventors
- 👤 Bernard G. Mandelik
- 👤 Walter A. Cronkright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:06
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; C; C01; C01F; C01F11/00; C01F11/46; C01F11/464
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
82 words
In a process for removing sulfur oxides from industrial waste gas by contacting the waste gas with a first aqueous medium containing sodium carbonate, calcium hydroxide, or calcium carbonate and precipitating calcium sulfite as a by-product, the improvement which comprises oxidizing at least part of the precipitated calcium sulfite to calcium sulfate with an oxygen-containing gas at an oxygen partial pressure of from about 2 to about 100 psia in a second aqueous medium containing at least 3 weight percent magnesium sulfate.
Claim 2
Dependent Claim
82 words
In a process for removing sulfur oxides from industrial waste gas by contacting the waste gas with a first aqueous medium containing sodium carbonate, calcium hydroxide, or calcium carbonate and precipitating calcium sulfite as a by-product, the improvement which comprises oxidizing at least part of the precipitated calcium sulfite to calcium sulfate with an oxygen-containing gas at an oxygen partial pressure of from about 2 to about 100 psia in a second aqueous medium containing at least 3 weight percent magnesium sulfate.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the first aqueous medium contains calcium hydroxide or calcium carbonate or mixtures thereof.
Claim 4
Dependent Claim
24 words
The process of claim 1 wherein the pH of the second aqueous medium is within a range of from about 5.0 to about 8.0.
Claim 5
Dependent Claim
33 words
The process of claim 1 wherein oxidation of said least part of the precipitated calcium sulfite is carried out under a partial pressure of oxygen from about 2 psia. to about 100 psia.
Claim 6
Dependent Claim
49 words
The process of claim 1 wherein the oxygen-containing gas is air which is passed through the second aqueous medium at a superficial velocity of from about 0.1 feet per second to about 1.0 feet per second and at a pressure of from about 10 psig. to about 100 psig.
Claim 7
Dependent Claim
19 words
The process of claim 2 wherein the second aqueous medium is a minor portion of the first aqueous medium.
Claim 8
Dependent Claim
19 words
The process of claim 2 wherein the second aqueous medium contains a minor portion of the first aqueous medium.
Claim 9
Dependent Claim
28 words
The process of claim 1 wherein oxygen and sulfur dioxide are present in the industrial waste gas at a concentration volume ratio of less than 125 to 1.0.
Claim 10
Dependent Claim
27 words
The process of claim 6 wherein the second aqueous medium contains magnesium sulfate in a concentration of from about 5 weight percent to about 27 weight percent.
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) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |