| abstract |
1. Method of chlorine-free bleaching of pulp, in particular pulp of artificial fibers, such as hardwood pulps, with a starting kappa value of 15-1, preferably 4-1, or paper pulp, such as wood pulp conifers, starting kappa values up to 30, preferably up to 10, with ozone, in which the pulp is suspended at a temperature of 15-80 ° C, preferably 40-70 ° C and at a pH value of 1-8, preferably 2-3 put into contact with the ozone-containing gas by violent felling or mixing, where the ozone-containing gas contains 20-300 g / m3, preferably 50-150 g / m3 of ozone, and a maximum of 2 % by weight, preferably 0.05-0.5% by weight of ozone, based on absolutely dry pulp, characterized in that a pulp suspension with a substance density of 3-20% by weight, preferably 5-20% by weight, in particular 7-15% by weight, and the ozone-containing gas is introduced under a pressure of 1-15-0.1 MPa, preferably 1.1-10-0.1 MPa, to a pulp suspension. PL PL PL |