Macmillan Bloedel Limited

Thomas Howard Murphy

Marco Solinas

Derek Barnes

Yonghao Ni

Roger Wayne Kozak

Robert G Norris

Adriaan Reinhard Van Heiningen

A bleached pulp having a high viscosity for a given permanganate number is formed by pretreating never dried pulp with an organic solvent medium to produce a treated pulp composed of said never dried pulp in the medium and then bleaching that treated pulp using ozone at a pH of 1.5-5 to provide a bleached pulp while reducing the viscosity loss during the ozone bleaching step significantly compared to that what would occur if the medium used in the ozone bleaching were water.

Ozone bleaching with an organic solvent and mineral acid

A strand orienter formed by a plurality of substantially planar parallel partition walls further includes a plurality of shafts extending substantially perpendicular to the partition walls, each mounting wipers in the passages in position to wipe strands that may tend to plug the orienter from the passages and off the upper edges of the partition walls over substantially the full length of these upper edges and thereby prevent plugging of the orienter.

Vane orienter with wipers

A process for bleaching pulp by impregnating the pulp with an aqueous organic solvent medium and then bleaching in an ozone stage (Z stage) to form a bleached pulp characterized in that organic solvent in the organic solvent medium accompanying the pulp through the ozone stage is neutralized and stripped from the bleached pulp leaving the ozone stage and the separated organic solvent is recovered for reuse.

Solvent recovery in pulp bleaching with ozone

A method of bleaching a chemical pulp by adjusting the pH of the pulp to 1.5-3.5, chelating the pulp and then treating the pulp in an N stage with nitric oxide (NO) in the amount of at least 1.5% by weight of the oven dried pulp at a consistency of between 30 and 55% and further treating the pulp in a Z stage with ozone to produce a bleach pulp having a higher viscosity for a given permanganate number compared with a similar pulp bleached without using the N stage.

Growing community of inventors

Burnaby, Canada

Thomas Howard Murphy