METHOD OF PRODUCING PULP USING SINGLE-STAGE COOKING WITH FORMIC ACID AND WASHING WITH PERFORMIC ACID

摘要

The invention relates to a method of producing pulp with a high brightness using single-stage cooking with formic acid, washing with performic acid and bleaching with oxidizing bleaching chemicals. In performic acid washing, the rapid formation and rapid reactions of performic acid (HCOOOH) are utilized for modification of residual lignin. The method of the invention provides an ISO brightness exceeding 90 % without chlorine chemicals. The method can be applied to both herbaceous plants and wood.