Patent US4655929A successfully refreshed from Google Patents.
US4655929A
Expired / Lapsed
US
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Process for processing waste solution containing ammonium ions and fluoride ions
Assignee: Mitsubishi Metal Corp
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Filing: 1985-04-01
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Granted: 1987-04-07
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Expires: 2005-04-01
Abstract
Abstract In a process for processing a waste solution containing ammonium ions and fluoride ions to recover ammoniacal water and anhydrous hydrogen fluoride, the waste solution is treated with a strong acid type ion exchange resin to separate ammonium ions; the resin is eluted with hydrochloric acid to recover ammonia as ammonium chloride; the effluent is distilled with addition of concentrated sulfuric acid to recover hydrogen fluoride; the remaining diluted sulfuric acid is concentrated and recycled to the hydrogen fluoride recovery step; the ammonium chloride solution is distilled with addition of magnesium hydroxide to recover ammonia water; the remaining formed magnesium chloride is thermally decomposed into hydrochloric acid and magnesium hydroxide, which are recycled to the regeneration of the ion exchange resin and the treatment of the ammonium chloride solution respectively.
Inventors
- 👤 Hiroshi Tanaka
- 👤 Toshiaki Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:47
CPC Classifications
C; C01; C01C; C01C1/00; C01C1/02; C01C1/10; C01B; C01B7/00; C01B7/19; C01B7/191; C01B7/194
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
167 words
A closed-system process for recycling of a waste solution containing ammonium ions and fluoride ions comprising the steps of: separating ammonium ions by ion exchange adsorption with a strong acid type ion exchange resin; recovering hydrogen fluoride by extractive distillation with addition of concentrated sulfuric acid; concentrating the remaining diluted sulfuric acid and recycling it to said extractive distillation step; regenerating said ion exchange resin which adsorbed ammonium ions with an aqueous solution of hydrochloric acid and reusing said resin from which ammonium ions have been removed for said adsorption of ammonium ions; recovering ammonia water from the remaining aqueous solution of ammonium chloride by distilling said aqueous solution of ammonium chloride with addition of magnesium hydroxide; recovering hydrochloric acid and magnesium hydroxide from the remaining solution containing magnesium chloride by hydrolytic thermal decomposition of said magnesium chloride; and recycling said hydochloric acid to said ion exchange resin regeneration step and recycling said magnesium hydroxide to said step of distilling ammonia water from said ammonium chloride solution.
Claim 2
Dependent Claim
167 words
A closed-system process for recycling of a waste solution containing ammonium ions and fluoride ions comprising the steps of: separating ammonium ions by ion exchange adsorption with a strong acid type ion exchange resin; recovering hydrogen fluoride by extractive distillation with addition of concentrated sulfuric acid; concentrating the remaining diluted sulfuric acid and recycling it to said extractive distillation step; regenerating said ion exchange resin which adsorbed ammonium ions with an aqueous solution of hydrochloric acid and reusing said resin from which ammonium ions have been removed for said adsorption of ammonium ions; recovering ammonia water from the remaining aqueous solution of ammonium chloride by distilling said aqueous solution of ammonium chloride with addition of magnesium hydroxide; recovering hydrochloric acid and magnesium hydroxide from the remaining solution containing magnesium chloride by hydrolytic thermal decomposition of said magnesium chloride; and recycling said hydochloric acid to said ion exchange resin regeneration step and recycling said magnesium hydroxide to said step of distilling ammonia water from said ammonium chloride solution.
Claim 3
Dependent Claim
29 words
The process as set forth in claim 1, wherein the waste solution containing ammonium ions and fluoride ions is the waste water from a nuclear uranium fuel production plant.
Claim 4
Dependent Claim
24 words
The process as set forth in claim 2, further comprising concentrating by distillation the diluted hydrogen fluoride solution which remains after said separating step.
Claim 5
Dependent Claim
24 words
The process as set forth in claim 1, further comprising concentrating by distillation the diluted hydrogen fluoride solution which remains after said separating step.
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) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |