Abstract: Process for bleaching lignocellulosic material comprising an oxygen bleaching treatment and an enzymatic treatment with a substantially cellulase-free xylanase, which process is compatible with, and can be incorporated into, conventional bleaching sequences. The process provides a delignified and bleached pulp using lower amounts of chlorine-containing compounds, and the opportunity of eliminating the use of elemental chlorine, thereby reducing the polluting effluent from a pulp mill employing the process. Also, a greater extent of delignification can be achieved while retaining acceptable pulp strength properties. The oxygen bleaching treatment and the enzynmatic treatment are done in series.

Abstract: A continuous two-stage peroxide bleaching process operated in a single bleach plant for producing a bleached pulp of high brightness, having a second stage bleaching step using a high charge of peroxide followed by a washing stage to recover the residual liquor containing a substantial amount of the applied peroxide. The residual liquor is recycled and used for bleaching in the first stage. Only a portion of the pulp bleached in the first stage is treated in the second stage. Two or more bleached pulp products can be produced simultaneously. The bleached pulp products can be used to form different layers of a multi-layer paper products.