High temperature peroxide bleaching of mechanical pulps

A method of making bleached mechanical pulps is disclosed for pulping mills having a primary and a secondary refiner. A first step is to provide cellulosic materials, such as wood chips to refine into the pulp; the wood chips have an initial brightness level. A second step is to provide a bleaching...

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Bibliographische Detailangaben
Hauptverfasser:	CAMPBELL ROGER O, HAMILTON ROBERT T, PARRISH ANTHONY, HAYNES KAAREN K, BROOKS ZEECHA L
Format:	Patent
Sprache:	eng
Schlagworte:	APPARATUS THEREFOR FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT PAPER-MAKING PRODUCTION OF CELLULOSE PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCESFROM CELLULOSE-CONTAINING MATERIALS REGENERATION OF PULPING LIQUORS TEXTILES TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKINGMACHINE
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Beschreibung
Zusammenfassung:	A method of making bleached mechanical pulps is disclosed for pulping mills having a primary and a secondary refiner. A first step is to provide cellulosic materials, such as wood chips to refine into the pulp; the wood chips have an initial brightness level. A second step is to provide a bleaching liquor to the refining system of the pulp mill, wherein the liquor comprises an amount of hydrogen peroxide and an amount of alkali having greater than 0% to 100% magnesium hydroxide or soda ash or a combination thereof. A third step is to hold the pulp with the bleaching liquor at a temperature in the range of about 85° to about 160° C. and for about 2 to about 180 minutes. The components of the bleach liquor can be added at