METHOD OF BLEACHING MATERIALS AND INTERMEDIATE PRODUCTS CONTAINING CELLULOSE Russian patent published in 2001 - IPC

FIELD: paper-and-pulp industry. SUBSTANCE: crude material is treated with chlorine dioxide in presence of sodium hydrocarbonate solution at concentration 0.01-1.00 M and temperature 10 to 50 C for 10 to 120 min. Low bleaching temperature enables environmentally safe neutralization of alkaline effluent by acidic industrial effluents and creates mild bleaching conditions preserving bleaching capacity of chlorine dioxide and reducing degradation of cellulose fibers by chlorites and chlorates formed upon interaction of chlorine dioxide with alkali metal hydroxides. EFFECT: improved environmental conditions and improved quality of cellulose product. 2 cl, 6 ex