A simple and practical pulp kappa test method for process control in pulp production

Through permanganate measurements, this study demonstrates a simple, rapid, practical, and direct spectrophotometric pulp kappa test method through on e calibration with a standard pulp sample of known kappa number. Two perman ganate absorption measurements were made in both the testing and standard p ulp-permanganate reacting solutions for kappa calculation, one at the begin ning of the reaction and the other at about 2-3 min into the reaction. The measured kappa numbers of 13 blended hardwood pulps and another 45 pulps fr om laboratory pulping of 10 hardwood and softwood species in a kappa number range of 10-70 are reported. The results showed excellent agreement with t hose obtained by the standard TAPPI kappa method. The effect of the pulp-pe rmanganate reaction temperature on measured kappa number using the present method is also presented. The method has the potential for on-line kappa mo nitoring in pulp production.