METHOD OF BLEACHING SULFATE CELLULOSE Russian patent published in 1998 - IPC

FIELD: pulp-and-paper industry. SUBSTANCE: deciduous sulfate cellulose is delignified by stabilized hydrogen peroxide solution at pH 10 ± 0.5, washed with water, and delignified by ozone. Delignification by hydrogen peroxide is conducted at 60-100 C until cellulose rigidity attains 30-60 permanganate units (about 5-11 Kappa units). Sodium silicate is utilized to stabilize peroxide solution. Concentration of mass being delignified is 10-20% and hydrogen peroxide consumption is 0.5-3.0%. EFFECT: increased selectivity in cellulose delignification by ozone and provided complete dissolution of reaction products directly in acid solution thanks to fuller lignin destruction. 2 cl, 1 dwg