TAPPI T236 om-22 PDF

Kappa number is a key test method for determining the level of lignin remaining in a sample of finished or in-process pulp. It is thus a measure of the completeness of the pulping process for many kinds of chemical and semi-chemical pulps, both bleached and semi-bleached. Kappa number is based upon the reaction of a strong oxidizing chemical, potassium permanganate, with lignin as well as small levels of certain other organic impurities remaining in the pulp at various stages of its processing. Kappa number gives the maker of the pulp, as well as the papermaking user of the pulp, valuable information about the properties of the pulp as well as the paper made from it, particularly with regard to the level of residual lignin present.