Recoverable regenerants for cationic exchange resins
AssigneeAerojet-General Corporation
InventorsArthur Katzakian, Jr., David O. DePree
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Abstract
An improved, closed-cycle process for regeneration of weakly acidic spent cation resins and for the recovery and recycle of the regenerants is disclosed. The improvement resides in the use of hydroxy or alkoxy substituted carboxylic acids as the cation resin regenerant. These acids and their metal salts are soluble and are high boiling and do not form azeotropes. When the spent cation regenerant is combined with the spent anion regenerant such as an amine salt, a weak, dissociable complex of the regenerants is formed and the metal salt is reconstituted. The complex is dissociated, preferably by distillation, into the separate regenerants which are recycled and the salt is recovered.
Claims15
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.sub.a, to regenerate said resin and to form a first effluent stream containing spent anion regenerant of the formula, R.sub.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.sub.c, selected from an hydroxy or alkoxy substituted alkanoic acid to regenate said resin and to form a second effluent stream containing spent cation regenerant of the formula, MR.sub.c ;
- 3. combining said first stream containing spent anion regenerant, R.sub.a X, with said second stream containing spent cation regenerant, MR.sub.c, to form a mixture containing a strongly dissociated, ionizable complex, R.sub.c R.sub.a, and reconstituted inorganic salt, MX;
- 4. dissociating the complex to free R.sub.c or R.sub.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.
Dependencies are inferred from the claim text.