Patent US3887498A successfully refreshed from Google Patents.
US3887498A
Expired / Lapsed
US
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Method for regeneration of cation exchange resins and for removal of iron deposits therefrom
Assignee: ATK Launch Systems LLC
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Filing: 1973-03-12
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Granted: 1975-06-03
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Expires: 1993-03-12
Abstract
Abstract A composition for preparing an aqueous solution for regenerating and removing iron from a cation exchange resin which has become exhausted and iron-fouled as the result of use in softening hard water, the composition comprising a major proportion of sodium chloride and a minor proportion of a source of nitrilotriacetic acid; and a method of regenerating said resin.
Inventors
- 👤 Eugene J Kuhajek
- 👤 Howard W Fiedelman
- 👤 Gordon H Tibbitts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:49
CPC Classifications
B; B01; B01J; B01J49/00; B01J49/50; B01J49/53
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
80 words
A METHOD HOF REGENERATING A CATION EXCHANGE RESIN WHICH HAS BEEN USED FOR SOFTENING HARD WATER AND WHICH HAS BECOME IRON-FOULD AND SUBSTANTIALLY EXHAUSTED BY REASON THEREOF, WHICH METHOD COMPRISES CONTACTING SAID RESIN WITH AN AQUEOUS SOLUTION CONTAINING ABOUT 10% BY WEIGHT OF SODIUM CHLORIDE AND BASED ON SODIUM CHLORIDE AT LEAST ABOUT 0.175% BY WEIGHT OF NITROLOTRIACETIC ACID, THE PH OF SAID AQUEOUS SOLUTION CONTAINING SAID SODIUM CHLORIDE AND SAID NITRILOTRIACETIC ACID BEING LESS THAN ABOUT 3 PH UNITS.
Claim 2
Independent Claim
80 words
A METHOD HOF REGENERATING A CATION EXCHANGE RESIN WHICH HAS BEEN USED FOR SOFTENING HARD WATER AND WHICH HAS BECOME IRON-FOULD AND SUBSTANTIALLY EXHAUSTED BY REASON THEREOF, WHICH METHOD COMPRISES CONTACTING SAID RESIN WITH AN AQUEOUS SOLUTION CONTAINING ABOUT 10% BY WEIGHT OF SODIUM CHLORIDE AND BASED ON SODIUM CHLORIDE AT LEAST ABOUT 0.175% BY WEIGHT OF NITROLOTRIACETIC ACID, THE PH OF SAID AQUEOUS SOLUTION CONTAINING SAID SODIUM CHLORIDE AND SAID NITRILOTRIACETIC ACID BEING LESS THAN ABOUT 3 PH UNITS.
Claim 3
Independent Claim
81 words
A method of regenerating a cation exchange resin which has been used for softening hard water and which has become iron-fouled and substantially exhausted by reason thereof, which method comprises contacting said resin with an aqueous solution containing about 10% by weight of sodium chloride and based on said sodium chloride at least about 0.175% by weight of nitrilotriacetic acid, the pH of said aqueous solution containing said sodium chloride and said nitrilotriacetic acid being less than about 3 pH units.
Claim 4
Independent Claim
81 words
A method of regenerating a cation exchange resin which has been used for softening hard water and which has become iron-fouled and substantially exhausted by reason thereof, which method comprises contacting said resin with an aqueous solution containing about 10% by weight of sodium chloride and based on said sodium chloride at least about 0.175% by weight of nitrilotriacetic acid, the pH of said aqueous solution containing said sodium chloride and said nitrilotriacetic acid being less than about 3 pH units.
Claim 5
Dependent Claim
46 words
The method of claim 1 wherein the nitrilotriacetic acid is derived from a combination of a sodium salt of nitrilotriacetic acid and an acidic donor, the quantity and acidity of said acidic donor being sufficient to provide said pH of less than about 3 pH units.
Claim 6
Dependent Claim
12 words
The method of claim 2 wherein the acidic donor is sodium bisulfate.
References Cited (Backward Citations)
US2769787A
Cited
US3099521A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |