Pulp - Determination of dust content

1 definition

(1) Any dust embedded in the pulp sheet, any impurity that is significantly different from the pulp sheet color can be observed with reflected light or transmitted light.

(2) The Dirt Count of pulp is expressed by the total area of ​​dust contained in each kilogram of pulp (mm2) or by the number of various types of dust.

2 instruments

① Dust measurement box.

②Standard map of dust.

③Tweezers with pointed nose and elbow.

④ Sheet former.

⑤Absorbent paper or filter cloth should be clean without any impurities or dust, so as not to contaminate the sample.

3 experimental steps

① Take samples according to standard methods, and measure their moisture (applicable to pulp board or block) or concentration (applicable to liquid pulp).

②Weigh an absolute-dry pulp sample equivalent to (25.0±1.0)g, and after dissociation, copy it into a 200g/m2 pulp sheet on a paper former, and dehydrate under pressure.

③Paste the slurry on the dust measurement box, and use the light in the box to peel off the sample layer by layer with sharp-nose elbow tweezers to pick out the dust in the slurry, and then compare the area on the dust standard map to calculate the dust. The total area (mm2). Or count the number of dust in each group according to Table 8-7.

4 Calculation of results