Release of organic substances from bleached sulphate pulps during slushing and refining

摘要

Mill experience has shown that different types of pulp have different abilities to release detrimental organic materi- al into the white water. In this work, the release of organic sub- stances from eight different bleached pulps (hardwood, softwood and eucalyptus) during slushing and refining at different salt con- centrations was evaluated. The refining trials were performed with an Escher Wyss laboratory refiner. Water samples were withdrawn from the refiner at several points during the refining and characterised with respect to a variety of chemical properties. The chemical analyses included several measures of the dissol- Ved substances, such as COD, total carbohydrate, total lignins, Anionic charge and conductivity. The samples were fractionated According to molecular mass (cut-offs 5 000 and 20 000) and Analysed further.