Diamond Shamrock Chemicals Company

Economics Laboratory, Inc.

Richard E Freis

Thomas R Oakes

James E Maloney

James F Maloney

An improved method of brown stock washing is disclosed. A nonionic surfactant in combination with a polyelectrolyte dispersant, and preferably a solvent, are utilized in the washing step in the pulping of virgin cellulosic fiber. The methods of the invention provide for the enhanced removal and recovery of cooking chemicals and organics from the pulp.

Method of brown stock washing

The method of substantially removing and dispersing resinous or waxy contaminants from contaminant-containing secondary fiber during repulping, is disclosed. The method includes combining the contaminant-containing secondary fiber in an aqueous repulping medium with a substituted oxyethylene glycol nonionic surfactant, and a water soluble, low molecular weight polyelectrolyte dispersant, at an elevated temperature.

Methods of decontaminating secondary fiber

Washing methods of deinking secondary cellulose fiber (i.e., removing unwanted non-cellulose materials therefrom) are disclosed. These washing methods (as opposed to flotation methods) generally involve deinking the fiber with surface active agent (surfactant). The present invention utilizes a single foam-suppressing surface active agent consisting essentially of

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Bloomington, MN, United States of America

Richard E Freis