METHOD OF WHITENING SULFATE CELLULOSE Russian patent published in 1997 - IPC

FIELD: pulp- and-paper industry. SUBSTANCE: 2-10% sulfate cellulose is first treated with chlorine dioxide for 30-120 min and then with hydrogen peroxide. In the first step, 0.07-0.12 chlorine dioxide per 1 Kapp unit is consumed while process is conducted at 50-100 C until absorption of reagent with pulp is completed. In the second step, 10-20% pulp is treated for 60-240 min at 70-100 C and pH 9.5-10.5 in presence of stabilizer for hydrogen peroxide, the latter being consumed in quantity 0.5-3.0% based on the quite dry cellulose weight. EFFECT: improved procedure. 3 cl, 3 tbl