METHOD FOR BLEACHING OF CELLULOSE STAPLE FIBERS Russian patent published in 1995 - IPC

FIELD: textile industry. SUBSTANCE: method for bleaching of cellulose staple fibers includes three-stage successive treatment of cellulose suspension with oxygen in alkali medium, ozone at elevated pressure and hydrogen peroxide at elevated temperature. Oxygen treatment in the first stage is carried out in the presence of hydrogen peroxide in the amount of 26-50 mas. in mixture, and temperature of 70-100 C (preferably 75 C). Waste gases after treatment with ozone containing oxygen are fully used in the first stage, and sewage of this stage is used for dilution of cellulose between the first and second treatment stages and/or decalcification of cellulose after bleaching. Alkali consumption at the first stage amounts to 2.5-5% of mass of absolutely dry cellulose. The second stage is conducted with mixture of oxygen and ozone, with the content of the latter amounting to 5-10 mas. at 40-70 C (preferably, 50-60 C). EFFECT: higher efficiency. 4 cl, 2 tbl