METHOD OF BLEACHING SULPHATE CELLULOSE Russian patent published in 2011 - IPC D21C9/10 D21C9/14 D21C9/16 

FIELD: chemistry.

SUBSTANCE: method involves treating cellulose with sulphuric acid at the first step after oxygen-alkaline treatment. At the second step, peroxide bleaching is carried out in an alkaline medium in the presence of a stabiliser - magnesium sulphate. The third step involves treating cellulose with chlorine dioxide with its consumption not more than 0.5% for hardwood pulp and with chlorine dioxide consumption of 0.5-0.7% of the weight of absolutely dry cellulose for soft wood pulp. At the fourth step, cellulose is treated with hydrogen peroxide in an alkaline medium.

EFFECT: reduced consumption of chlorine dioxide, reduced corrosion of equipment and high environmental safety of the process.

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