International Paper Company

Shyam S Bhattacharjee

Vacheslav M Yasnovsky

Jean J Renard

Michael N Hull

Jamshed N Lam

A process for bleaching cellulosic pulp to a G.E. brightness of at least about 75 and a viscosity of at least about 14 wherein the effluent from the bleaching process is of reduced colored matter content and exhibits reduced COD. The process comprises DZD stages without interstage treatment of the pulp other than by an optional water wash.

Method for the bleaching of pulp in a D2D sequence wherein the effluent

An elementally chlorine-free method for the delignification and bleaching of pulp which involves the use of a neutral monoperoxysulfate bleaching step to delignify and thus brighten the pulp. The process achieves good selectivities above about 3 even at high delignification degrees of 60% or greater.

Neutral monoperoxysulfate bleaching process

An electrochemical process for delignification and bleaching of pulp fibers is disclosed. The process involves the use of metallic chlorates and vanadium catalysts in the presence of an electric current to provide a pulp fiber of improved brightness and viscosity.

Electrochemical process for bleaching wood pulp using chlorate and a

Extraction of chlorine bleached kraft wood pulps with aqueous peracids at pH values of 7 or below, aqueous sulfites at pH values below 10 or with certain non-aqueous solvents provides extracted pulps having lower residual color and permits use of lesser quantities of alkali or chlorine dioxide in subsequent bleach steps to attain brightness and strength levels comparable to those attained with pulps treated by alkaline extraction at pH values of 10 or higher. At a comparable level of alkali and chlorine dioxide or hypochlorite application, extraction of chlorinated pulp with peracids provides bleached pulps with enhanced brightness.

Growing community of inventors

Monroe, NY, United States of America

Shyam S Bhattacharjee