Electrochemical process for bleaching wood pulp using chlorate and a redox catalyst
AssigneeInternational Paper Company
InventorsShyam S. Bhattacharjee, Michael N. Hull, Vacheslav M. Yasnovsky
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Abstract
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.
Claims16
An electrochemical process for the delignification and bleaching of cellulosic pulp fibers which comprises the steps of:
- (a) mixing said pulp fibers with a solution comprising a metal chlorate and a vanadium compound as a catalyst to form an untreated slurry;
- (b) passing an electric current through said pulp slurry maintained at a pH less than 4.0 to form a treated slurry;
- (c) pressing and washing said treated slurry to remove said pulp fibers from said treated solution.
An electrochemical process for the delignification and bleaching of cellulosic pulp fibers which comprises the steps of:
- (a) mixing said pulp fibers with a solution comprising a metal chlorate wherein the concentration of said metal chlorate is within the range from about 0.1M/L to 1M/L and a vanadium compound wherein the concentration of said vanadium compound is within the range from about 0.1 mM/L to about 5.0 mM/L, as a catalyst to form an untreated slurry;
- (b) passing an electric current ranging from about 1,350 coulombs/lb pulp to about 13,500 coulombs/lb pulp through said pulp slurry maintained at a pH ranging from about 1.5 to about 2.5;
- and
- (c) pressing and washing said treated slurry to remove said pulp fibers from said treated solution.
An electrochemical process for the delignification and bleaching of cellulosic pulp fibers comprising the steps of:
- (a) passing an electric current through a solution containing a metal chlorate and a vanadium compound whereby V.sup.4+, chlorine dioxide and other reduced chlorine species are generated to form a treated solution;
- (b) mixing said treated solution with said pulp fibers to form a treated slurry;
- and
- (c) pressing and washing said treated slurry to remove said pulp fibers from said treated solution.
Dependencies are inferred from the claim text.