METHOD OF BLEACHING CELLULOSE Russian patent published in 1999 - IPC

FIELD: pulp industry; production of bleached cellulose without molecular chlorine and chlorine dioxide. SUBSTANCE: cellulose having rigidly of permanganate number 83 is subjected to alternating treatment by oxygen-containing reagents at five stages: hydrogen peroxide in alkaline medium and potassium permanganate in sulfate solution at stages 11 and IV; alkaline medium at stages I, III and V. Bleaching of sulfate cellulose by hydrogen peroxide is performed at 70 to 100 C at consumption of 2% and concentration of cellulose mass of 2 to 7%. Treatment with potassium permanganate is performed at consumption of 0.01 to 0.8% at 18 to 25 C till complete absorption. EFFECT: possibility of obtaining whiteness of cellulose of 83 to 85 % by ecologically clean method without using chlorine-containing reagents. 1 tbl, 8 ex