Electrochemical bleaching of wood pulps

Patent 4617099 Issued on October 14, 1986. Estimated Expiration Date:

December 23, 2005. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

747234

2307137

Inventors

Assignee

The Mead Corporation

Application

No. 06/812142 filed on 12/23/1985

US Classes:

205/690Bleaching

Examiners

Primary: Andrews, R. L.

Attorney, Agent or Firm

Biebel, French & Nauman

International Class

D21C 9/10 (20060101)

Abstract

A process for electrochemically bleaching pulp which comprises dispersing a pulp in a solution of sodium chloride to provide a first pulp slurry; subjecting said pulp slurry to electrolysis at a pH in the range of about 0 to 2.0; filtering said pulp slurry to remove said pulp; dispersing said pulp in a second solution of sodium chloride to provide a second pulp slurry; subjecting said second pulp slurry to electrolysis at a pH greater than 8.0; and recovering said pulp.

Other References

M M. Nassar, O. A. Fadaly, and G. H. Sedahmed, "A New Electrochemical Technique for Bleaching Cellulose Pulp," J. Applied Electrochemistry, 13, 663 (1983)
M. M. Nassar, "Effect of a Chromium Salt on the Electrochemical Bleaching of Sulphite Pulp," Surface Technology, 21, 301 (1984)
M. M. Nassar, "Electrochemical Bleaching--A Novel Method for Bleaching Kraft and Sulphite Pulps," J. of Pulp and Paper Science, vol. 11, 17 (1985)