Ionics, Inc.

Bruce T Batchelder

Russell James MacDonald

Li Zhang

Keith James Sims

Arthur L Goldstein

Wayne A McRae

Irving D Elyanow

Improved electrodialysis (ED) stacks are disclosed having one or more components selected from the group:

Electrodialysis including filled cell electrodialysis

Improved electrodialysis (ED) stacks are disclosed having one or more components selected from the group: a) cation exchange membranes having ion exchange groups predominantly sulfonic acid groups and a minor amount of weakly acidic and/or weakly basic groups or membranes which are selective to monovalent cations and simultaneously therewith, cation exchange granules selective to monovalent cations as packing in the dilute compartments; b) anion exchange membranes having as ion exchange groups only quaternary ammonium and/or quaternary phosphonium groups and substantially no primary, secondary and/or tertiary amine and/or phosphine groups or membranes which are selective to monovalent anions simultaneously therewith, anion exchange granules selective to monovalent anions as packing in the dilute compartments; c) as packing in the dilute compartment, anion exchange granules which are selective to monovalent anions, or cation exchange granules which are selective to monovalent cations, or cation exchange granules having as exchange groups a predominant amount of sulfonic acid groups and a minor amount of weakly acidic and/or weakly basic groups, or anion exchange granules consisting of organic polymers having as anion exchange groups only quaternary ammonium and/or quaternary phosphonium groups and almost no primary, secondary and/or tertiary amine and/or phosphine groups.

A process for demineralization of whey-based material using electrodialysis. The process involves increasing the conductivity of the diluting stream, i.e, the stream containing the material to be demineralized, at one or more points in time during the electrodialysis cycle. When removal of divalent ions is desired, the increased conductivity may occur by the addition of salts of monovalent ions.

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North Reading, MA, United States of America

Bruce T Batchelder