US3941693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid mineral and regenerant recovery for ion-exchange resins
Assignee: Aerojet Rocketdyne Inc
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Filing: 1974-08-12
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Granted: 1976-03-02
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Expires: 1994-08-12
Abstract
Abstract Recovery of ion-exchange regenerants and precipitation of mineral salts is disclosed. The spent cation and anion regenerant streams are combined to form a weak dissociable complex of the regenerants and to reconstitute the removed inorganic mineral salt. The mixture is adjusted stoichiometrically to balance the anion and cation of the removed salt. The salt is precipitated by limiting solubility thereof either by concentrating the mixture or by reducing the solubility of the salts therein, suitably by the addition of a water-miscible solvent such as methanol. The complex is dissociated to reconstitute the separate anion and cation regenerants which are adjusted to the appropriate solvent concentration for recycle and reuse. Excess water in the system provided by water of hydration released by the resin during regeneration or by washing steps is removed prior, during or after separation of the regenerants depending on the nature of the separation technique employed and the optimum time for precipitation and removal of the mineral salts. Separation and recovery of the regenerants may be accomplished by distillation of regenerants having disparate volatilities, solvent extraction using an immiscible solvent having preferential solubility for one of the regenerants or by forming an insoluble complex of one of the regenerants. The recovered regenerants are reused as regenerants for spent anion and cation resin columns and the precipitated slats are removed by filtration, sedimentation or centrifugation.
Inventors
- 👤 David O. DePree
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:05
CPC Classifications
B; B01; B01J; B01J49/00; B01J49/50
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
123 words
A method of recovering and recycling spent ion-exchange regenerants comprising the steps of: 1. passing through a first, separate bed of spent, weakly-basic, anion exchange resin containing bound inorganic anion, X, a weak organic base anion regenerant, R a , to regenerate said resin and to form a first effluent stream containing spent anion regenerant of the formula, R a X; 2. passing through a second, separate bed of spent, weakly acidic cation exchange resin containing bound inorganic cation, M, a cation regenerant, R c , selected from organic complexing agents for the inorganic cation, M, and weakly acidic organic carboxylic acids to regenerate said resin and to form a second effluent stream containing spent cation regenerant of the formula, MR c ;
Claim 2
Independent Claim
123 words
A method of recovering and recycling spent ion-exchange regenerants comprising the steps of: 1. passing through a first, separate bed of spent, weakly-basic, anion exchange resin containing bound inorganic anion, X, a weak organic base anion regenerant, R a , to regenerate said resin and to form a first effluent stream containing spent anion regenerant of the formula, R a X; 2. passing through a second, separate bed of spent, weakly acidic cation exchange resin containing bound inorganic cation, M, a cation regenerant, R c , selected from organic complexing agents for the inorganic cation, M, and weakly acidic organic carboxylic acids to regenerate said resin and to form a second effluent stream containing spent cation regenerant of the formula, MR c ;
Claim 3
Dependent Claim
89 words
combining said first stream containing spent anion regenerant, R a X, with said second stream containing spent cation regenerant, MR c , to form a mixture containing a strongly dissociated, ionizable complex, R c R a , and reconstituted inorganic salt, MX; 4. dissociating the complex to free R c or R a regenerant; 5. separating one of the regenerants from the mixture and recycling it to one of said beds; and 6. separating the remaining regenerant from the mixture and recycling it to the other of said beds.
Claim 4
Dependent Claim
89 words
combining said first stream containing spent anion regenerant, R a X, with said second stream containing spent cation regenerant, MR c , to form a mixture containing a strongly dissociated, ionizable complex, R c R a , and reconstituted inorganic salt, MX; 4. dissociating the complex to free R c or R a regenerant; 5. separating one of the regenerants from the mixture and recycling it to one of said beds; and 6. separating the remaining regenerant from the mixture and recycling it to the other of said beds.
Claim 5
Dependent Claim
39 words
A method according to claim 1 in which the first and second streams are combined in a manner to sotichiometrically adjust the amount of MR c combined with R a X such that MX is formed in the mixture.
Claim 6
Dependent Claim
17 words
A method according to claim 1 further including the step of removing said salt from the mixture.
Claim 7
Dependent Claim
21 words
A method according to claim 3 in which the concentration of the salt is increased until it precipitates from the mixture.
Claim 8
Dependent Claim
27 words
A method according to claim 4 in which the concentration step is effected on the residue of the mixture after separation of one of said regenerants therefrom.
Claim 9
Dependent Claim
20 words
A method according to claim 1 in which each of the streams contain at least 5% by weight of water.
Claim 10
Dependent Claim
27 words
A method according to claim 6 further including the step of reducing the amount of water in at least one of said streams before they are combined.
Claim 11
Dependent Claim
19 words
A method according to claim 6 further including the step of reducing the concentration of water in the mixture.
Claim 12
Dependent Claim
27 words
A method according to claim 1 further including the step of adjusting the concentration of the separated regenerants before recycling them to regenerate spent ion-exchange resin beds.
Claim 13
Dependent Claim
30 words
A method according to claim 1 in which the recycled regenerant is provided in at least a 30% stoichiometric excess with respect to ion loading of the ion-exchange resin bed.
Claim 14
Dependent Claim
13 words
A method according to claim 10 in which said excess is from 50-200%.
Claim 15
Dependent Claim
18 words
A method according to claim 1 in which the pK of the regenerants is between 5 and 7.
Claim 16
Dependent Claim
29 words
A method according to claim 12 in which the anion regenerant is a weak organic base having a pK magnitude at least 2 more basic than the anion resin.
Claim 17
Dependent Claim
20 words
A method according to claim 13 in which the anion regenerant is an amine having a molecular weight below 500.
Claim 18
Dependent Claim
68 words
A method according to claim 14 in which the amine regenerant is selected from compounds of the formula: ##EQU5## where R 1 , R 2 and R 3 are selected from hydrogen, alkyl, alkynyl, alkenyl, aryl, alkaryl, aralkyl, alkoxy and may be substituted with hereto atoms or groups such as hydroxyl, ether, halogen, cyano; or R 2 and R 3 may be linked to form a cycloaliphatic structure.
Claim 19
Dependent Claim
35 words
A method according to claim 15 in which the amine is selected from the group consisting of N,N-dimethylethylamine, trimethylamine, dimethylamine, pyridine, N-methylmorpholine, N,N-dimethyl-2-methoxyethyl amine, isopropanol amine, tri-n-octyl amine, tri-n-decyl amine, N,N-diethylmethylamine, triethylamine and dimethylethanol amine.
Claim 20
Dependent Claim
24 words
A method according to claim 1 in which said inorganic cation complexing agents form organic soluble chelates and are selective toward the metal M.
Claim 21
Dependent Claim
37 words
A method according to claim 17 in which the chelates are selected from diketones, esters, amides, nitrocompounds, amines, amine acids, hydroxyl compounds and combinations thereof capable of enol formation and complexation with metal ions to form chelates.
Claim 22
Dependent Claim
21 words
A method according to claim 18 in which the chelates are selected from nitrodiphenylamines and β-diketones having a single exchangeable hydrogen.
Claim 23
Dependent Claim
12 words
A method according to claim 19 in which the chelate is 2-acetylcyclohexanone.
Claim 24
Dependent Claim
32 words
A method according to claim 3 in which separation is accomplished by distilling one of said regenerants from the mixture and one of said regenerants is substantially more volatile than the other.
Claim 25
Dependent Claim
25 words
A method according to claim 21 in which the boiling point of the more volatile regenerant is at least 10°F less than the other regenerant.
Claim 26
Dependent Claim
29 words
A method according to claim 22 in which the more volatile regenerant is an amine anion resin regenerant and at least 80% of the amine is separated and recovered.
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) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |