The Effect of Process Variables in Chlorine Dioxide Prebleaching of Birch Kraft Pulp. Part 2. AOX and OX Formation

摘要

Chlorine dioxide prebleaching (D_0-stage) is known to produce some chlorinated organic compounds. This article presents the development of AOX and OX as a function of time under various prebleaching conditions for oxygen delignified hardwood pulp. It was observed that OX is formed more rapidly than AOX and its amount was less affected by a preceding A-stage. Temperature had little effect on chlorination. Using mill filtrate instead of water for dilution increased the amount of AOX formed while the amount of OX remained unchanged. Higher charges of chlorine dioxide expectedly increased chlorination during a D_0-stage.