Polyacrylamide is currently widely used in paper mills to produce dry strength agents, etc. Recently, many friends have reported that polyacrylamide is very troublesome when it is dissolved, and it is easy to agglomerate if workers do not know the mixing process or are irresponsible.
1. The stirring and dissolving time of polyacrylamide is not easy to be too long. Although polyacrylamide is easily soluble in water, when its dissolved concentration reaches more than 10%, it will form a transparent gel in water and lose its fluidity. If a large amount of polyacrylamide is added instantaneously during the dissolution process, a dissolution system with a concentration greater than 10% will form in a certain area of the water, making the dissolution process difficult to continue. Therefore, it is necessary to add a certain amount of clean water until the stirring blade is gone, then start the stirrer to circulate the aqueous solution before adding polyacrylamide. It is required that the stirring blade should not have corners or blades, otherwise it will cause hanging and shearing. The unfavorable effect of acrylamide molecular chain makes the dissolved concentration inaccurate and weakens its dispersion effect. The dissolved concentration of polyacrylamide is not easy to be too high, generally around 0.5-1 per thousand. The stirring and dissolving time of polyacrylamide is not easy to be too long, and the general stirring time is about 1-1. 5 hours, otherwise its dispersion effect will be destroyed.
2. Polyacrylamide should be used and dissolved now, because the aqueous solution of polyacrylamide will automatically hydrolyze within 20-48 hours, lose its viscosity, and eventually lose its dispersion.
3. When polyacrylamide is dissolved, it is impossible to completely dissolve 100%. There must be a small part of the gel mass that is not completely dissolved. Therefore, filtration equipment must be added during application to prevent these gel masses from entering the paper machine, hanging the net and Sticky felt or produce paper defects.
4. When the paper machine starts to string water, it is necessary to add polyacrylamide first, so that there is polyacrylamide in the system to prevent the undispersed long fiber from agglomerating, so that the production can reach the normal state relatively quickly. Since polyacrylamide cannot be added too much at one time, it must be added uniformly, uniformly, and dispersedly. And the speed of addition should not be too fast, generally around 0.15 kg/min. When the polyacrylamide is added to the water, clean water with a certain pressure must be injected into its addition point, so that it will be diluted and dissolved immediately after being added to the water to achieve a good dissolution effect.
5. When the amount of polyacrylamide added changes, the dehydration speed of the pulp on the paper machine will change accordingly. If the amount of polyacrylamide added is adjusted too large, dehydration will occur too fast or too slow, which will affect the normal and stable production. Therefore, during the normal production of the paper machine, do not adjust the amount of polyacrylamide arbitrarily. The preferred ion type of polyacrylamide used in long fiber dispersant is anionic or non-ionic.
Post time: Apr-25-2021
