# US 4,393,202 A · Method for dewatering starch slurries containing swollen starch granules resulting from treatment with cationic reagents

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- Number: US 4,393,202 A
- Document ID: US4393202A
- Status: Granted
- Kind: A
- Application number: 06/408,987
- Filed: 1982-08-17
- Granted: 1983-07-12
- Earliest claimed: 1982-08-17
- Assignees: National Starch and Chemical Corporation
- Inventors: William F. Breuninger
- Web page: https://patentgrep.com/patent/US4393202A

## CPC

- C08B 31/00: Preparation of derivatives of starch (derivatives of amylose C08B33/00; derivatives of amylopectin C08B35/00)
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)

## Abstract

The production rate and yield resulting from the dewatering of starch conversion products containing swollen starch granules resulting from treatments with cationic reagents is improved by the addition to the starch slurry of a water soluble anionic polymer.

## Claims

### Claim 1

In a process for dewatering starch conversion products containing swollen starch granules resulting from treatment with cationic reagents, the improvement which comprises adding to the starch slurry a water soluble anionic polymer, thereby increasing the production rate and yield while reducing suspended solids in the effluent.

### Claim 2 (depends on 1)

The process of claim 1 wherein the water soluble anionic polymer is selected from the group consisting of homo- and copolymers of alkali metal styrene sulfonates, alkali metal and ammonium salts of high copolymers of styrene and substituted styrene with maleic acid; homo- and copolymers of sulfoalkyl acrylates and carboxyalkyl acrylates; and carboxyalkyl cellulose ethers.

### Claim 3 (depends on 1)

The process of claim 1 wherein the water soluble anionic polymer is an anionic derivative of starch prepared by the etherification or esterification of starch with carboxyalkyl, sulfoalkyl, sulfocarboxyalkyl and/or phosphate groups.

### Claim 4 (depends on 1)

The process of claim 1 wherein the water soluble anionic polymer is used in an amount of 0.01-0.5% by weight, based on the weight of starch solids.

### Claim 5 (depends on 1)

The process of claim 1 wherein the water soluble anionic polymer is a homo or copolymer polystyrene.

### Claim 6 (depends on 1)

The process of claim 1 wherein the starch conversion products are dewatered by washing in a continuous certifugal device.