US3630674A
Expired / Lapsed
US
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Bleaching of alkali metal hydroxide solutions
Assignee: Hooker Chemical Corp
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Filing: 1969-06-13
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Granted: 1971-12-28
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Expires: 1989-06-13
Abstract
Abstract Consistent color removal from aqueous alkali metal hydroxide solutions is obtained by prebleaching such solutions with a chlorine bleaching agent, and then afterbleaching the product with hydrogen peroxide.
Inventors
- 👤 James G Davidson Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:10
CPC Classifications
C; C01; C01D; C01D1/00; C01D1/04; C01D1/28; C01D1/36
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
18 words
The process of claim 1, wherein the alkali metal hydroxide solution is a 50 percent sodium hydroxide solution.
Claim 2
Dependent Claim
28 words
The process of claim 1, wherein the chlorine bleaching agent is a chlorine bleach solution containing from about 75 to about 130 grams of available chlorine per liter.
Claim 3
Dependent Claim
13 words
The process of claim 1, wherein the chlorine bleaching agent comprises chlorine gas.
Claim 4
Dependent Claim
27 words
The process of claim 1, wherein the hydrogen peroxide is added as a solution containing from about 5.5 to about 10 percent by volume of hydrogen peroxide.
Claim 5
Dependent Claim
43 words
The process of claim 2, wherein the hydrogen peroxide is added as a solution containing from about 5.5 to about 10 percent by volume by hydrogen peroxide in amounts of from about 0.001 to about 0.01 percent by volume of the prebleached solution.
Claim 6
Dependent Claim
50 words
The process of claim 2, wherein the chlorine bleaching agent is a sodium hypochlorite solution containing from about 75 to about 130 grams of available chlorine per liter which is added to the hydroxide solution in amounts of from about 0.13 to about 0.20 volume percent of the hydroxide solution.
References Cited (Backward Citations)
US2366546A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |