Blekning av massa

摘要

A method of oxygen delignification of pulp from lignocellulosic material. The oxygen delignification is carried out in two steps where the pulp concentration in the first step is 25-40% and in the second step 8-16%. The temperature in the second step shall be at least as high as in the first step, and the staytime in the first step shall be shorter than in the second step.