American Air Liquide, Inc.

Other

Sebastien Corbeil

V S Meenakshi Sundaram

Derek Hornsey

Steven A Fisher

Meenakshi V Sundaram

Michel Epiney

The present invention provides a process for preparing polysulfide. More particularly, the process of the present invention allows one to prepare the amount of polysulfide needed using clarified white liquor, and to be used when and where it is needed during the cooking process. The process comprises reacting alkaline digesting liquor after clarification with a catalytic amount of a transition metal oxide catalyst, most preferably manganese dioxide. The reaction is conducted at a temperature of 98&#xb0; C. or less, and is conducted for a short period of time, e.g., less than five minutes, with no oxygen gas or air being introduced with the catalyst and the main flow of clarified liquor.

Process for preparing polysulfides using clarified white liquor

Provided is a process for bleaching pulp with ozone. The process involves preparing a slurry of cellulosic pulp having a consistency in fibers of from 1-5 weight %. Such a low consistency slurry is then mixed with ozone under high shear conditions. The ozone is then maintained in contact with the cellulosic fibers to effect bleaching of the fibers. The present process offers the advantages of bleaching using a low consistency slurry, with the added advantages of employing ozone.

Ozone bleaching of low consistency pulp

Process for ozone bleaching of low consistency pulp

Methods of bleaching cellulose pulp using chlorine dioxide and ozone in one and the same single stage of a bleaching sequence having a plurality of stages are presented. In its broadest embodiment the method comprises controlling a ratio of chlorine dioxide to ozone within a single stage of a first bleaching sequence in a range effective to achieve strength characteristics of a final paper elaborated from the first bleaching sequence at least as great as strength characteristics when compared to a control bleaching sequence, the control bleaching sequence being the same in all respects as the first bleaching sequence except not employing ozone in a stage, and for essentially the same final brightness of pulp elaborated from the first and the control bleaching sequence. Cellulose pulps made using the methods of the invention are also described.

Method to improve final bleached pulp strength properties by adjusting the CI02:03 ration within a single (D/Z) stage of the bleaching process

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Willowbrook, IL, United States of America

Sebastien Corbeil