| abstract |
IN THE PROCEDURE FOR CHLORINE-FREE BLEACHING OF CELLULOSE THROUGH OZONE, A CELLULOSE SUSPENSION AT A TEMPERATURE OF 15-80 C, PREFERABLY 40-70 C, AND WITH A PH-VALUE OF 1-8, PREFERABLY 2-3 , CONTACT WITH A GAS CONTAINING OZONE UNDER AGITATION OR INTENSE MIXTURE. THE GAS CONTAINING OZONE CONTAINS 20-300 G / M HIGH 3, PREFERABLY 50-150 G / M HIGH 3 OZONE. IT IS USED AS A MAXIMUM 2% IN MASS, PREFERABLY 0.05-0.5% IN OZONE MASS, WITH REGARD TO ATROCELULOSE. TO MAKE THIS PROCEDURE APPROPRIATE FOR A CELLULOSE SUSPENSION IN THE MEDIUM CONSISTENCY ZONE (MC), THAT IS, FOR A CELLULOSE SUSPENSION WITH A DENSITY OF 3-20% BY MASS, PREFERABLY 5-20% BY MASS, ESPECIALLY 7-15% BY MASS, THE OZONE CONTAINING GAS ACCORDING TO THE INVENTION IS INTRODUCED WITH A PRESSURE OF 1-15 BARS, PREFERABLY 1,1-10 BARS, IN THE CELLULOSE SUSPENSION. THE PROCEDURE MAY ALSO BE PERFORMED ONE OR MORE TIMES IN A MULTIPLE PHASE BLEACHING PROCEDURE. |