Correct use of papermaking white water

1. When producing the relatively high-grade paper grades, the part of the stock sent from the chemical pulping workshop to the paper workshop produces white water, which affects the toning and sizing of the paper machine due to the high residual chlorine content. Generally, it is directly reused in the paper workshop, and this part of the water can be reused again in the pulping workshop.
2. White water reuse generally contains various additives such as fine fibers, fillers, and sizing materials. When the suspended solids content is high, the ash content of the finished paper will increase, thereby affecting the strength of the paper sheet.
3. White water reuse has been recycled for many times, and the microorganisms in the water multiply, which is easy to cause sludge blocks in the pulp system, and the microorganisms that are easy to fog and then accumulate in the pulp tank and pipe walls fall off and mix into the pulp, causing paper holes and paper machine breaks.
4. Due to the use of fillers and other salts, the calcium and magnesium ions in the white water increase, and the hardness of the water increases. Hard water is unfavorable for the sizing of paper. For acid sizing, because Ca2+ and Mg2+ in water will interact with the saponified sizing material to form insoluble calcium soap and magnesium soap, resulting in the loss of rosin size.

5.In the paper machine white water with AKD sizing, due to the high fiber on the filler surface, the sizing material tends to be adsorbed on the filler surface, and the AKD adsorbed on the filler surface will not have a positive effect on sizing.

If the filler is not retained, the rubber material will also flow into the white water. If this part of the white water is reused again, some of the rubber originally adsorbed by the filler will be redistributed on the surface of the fiber.

6.The reuse of white water also has a great influence on the dyeing of paper. On the one hand, because white water contains some toners, which is beneficial to the toning of paper, the stability of white water reuse plays an important role in the stability of paper; on the other hand, due to the increase of white water hardness, direct dyes will Decreases the dyeing power of dyes.

7.During the papermaking process, due to the presence of wood slag, resin acid, sizing agent, retention aid and other surfactants in the pulp, a large amount of foam is generated in the white water, and the gas in the reused white water will cause the pressure head of the paper machine to generate fluctuation. At the same time, it is not conducive to the dirty water in the wire part, and the "eyes of needles" appear on the paper, which will ultimately affect the product quality.

8.The reuse of papermaking white water is conducive to the stability of the pH value of the slurry on face wire.