treatment of pulp with a complexing agent in at least two blandningssteg without intermediate washing

摘要

A method of chlorine-free bleaching of pulp where metals are removed by means of a chelating agent. The chelating agent is admixed to the pulp in at least two subsequent mixing steps without intermediate washing. The stay-time between the mixing steps shall be less than 15 minutes, and the pulp is washed after the last mixing step.