PROCESS FOR BLEACHING OF CHEMICAL PULP

摘要

A process for the bleaching or delignification of a chemical pulp with oxygen chemicals, in which process the pulp is treated with a chelating agent in order to bind into a chelate complex the heavy metals present in the pulp. The chelating agent used is a nitrogen-containing chelating agent and a mixture of one or more compounds according to Formula (I): R1CnHm(OH)p(COOH)qR2, in which formula n is 1-8, m is 0-2n, p is 0-n, q is 0-2, R1 is COOH, and R2 is H, CH2OH or COOH.