Abstract: A method of bleaching chemical pulp with xylanase after chemical bleaching is provided. The method comprises the steps of exposing chemical pulp to a chlorine dioxide bleaching stage to produce a partially bleached pulp, treating the partially bleached pulp with a xylanase in an enzyme treatment stage at a pH of about 3 to about 8, then carrying out an alkaline extraction of the pulp. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.

Abstract: The present invention discloses methods of bleaching chemical pulp with xylanase after chemical bleaching. The method comprises the steps of treating chemical pulp with a first xylanase in a first enzyme treatment stage to produce an enzyme treated pulp, exposing the enzyme treated pulp to a chemical bleaching stage to produce a partially bleached pulp, and treating the partially bleached pulp with a second xylanase in a second enzyme treatment stage at a pH of about 3 to about 8. Further, there is disclosed a method of bleaching pulp comprising the steps of exposing chemical pulp to a chlorine dioxide bleaching stage to produce a partially bleached pulp, treating the partially bleached pulp with a xylanase in an enzyme treatment stage at a pH of about 3 to about 8, then carrying out an alkaline extraction of the pulp. The pulp bleaching method of the present invention may be performed in a pulp mill as part of a complex pulp bleaching process.