METHOD FOR REDUCING CHLORINATED COMPOUNDS PRODUCED DURING CHLORINATION STAGE BLEACHING OF PULP

摘要

A chlorination stage bleaching method is disclosedwhich comprises suppressing formation of polychlorinated dioxinsand furans without resulting in cellulose degradation and poorpulp viscosity by controlling the molecular chlorine:hypochlorousacid ratio by adding the chlorine to the pulp in multiple chargesand by adding an alkaline material to the pulp during thechlorination stage such that chlorination stage pH is controlledto a value from above about 1.8 to below about 3.5.