Method for rapidly determining a pulp kappa number using spectrophotometry
Assigneelnstitute of Paper Science and Technology, Inc
InventorsXin-Sheng Chai, Jun Yong Zhu
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Abstract
A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO2). Consequently, spectral interference from the precipitated MnO2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.
Claims13
A method for determining a pulp kappa number for a pulp sample, comprising the steps of:
- (a) mixing continuously a pulp-reacting solution, said pulp-reacting solution comprising:
- 1) a predetermined amount of pulp containing fibers and 2) a predetermined amount of reacting solution, said reacting solution having strong acidification and including an oxidation agent, where mixing the pulp-reacting solution causes an oxidation reaction in the pulp-reacting solution, and where the strong acidification of the reacting solution has an H+ concentration that limits the production of precipitated MnO2 such that precipitated MnO2 is insignificant;
- (b) filtering the pulp-reacting solution to limit fiber flow;
- (c) subjecting at least a segment of the fiber filtered pulp-reacting solution to light, wherein the light is partially absorbed by the oxidation agent in the pulp-reacting solution;
- (d) generating a time-dependent absorption spectral intensity from the absorption of the light by the oxidation agent in the pulp-reacting solution;
- (e) collecting the time-dependent absorption spectral intensity by an absorption spectrographic method to determine an absorption spectral intensity for the oxidation agent;
- (f) analyzing the time-dependent absorption spectral intensity using an oxidation reaction kinetic analysis to determine an oxidation reaction end point;
- and
- (g) calculating a pulp kappa number for the pulp sample based on the predetermined amount of pulp, the predetermined amount of reacting solution, the absorption spectral intensity of the oxidation agent before the oxidation reaction, and the absorption spectral intensity of the oxidation agent at the oxidation reaction end point.
Dependencies are inferred from the claim text.