How should retention aid be used

It is well known that polyacrylamide does not dissolve completely when dissolved. There will be a small part of the retention aid that is not completely dissolved. Therefore, when used, it is necessary to add filtration equipment to prevent these gummy products from entering the paper mill, hanging the net, sticking the cloth or producing paper cakes.

When the paper machine starts watering, polyacrylamide should be added first to make the polyacrylamide present in the system, prevent the long fiber from caking, so that the production reaches the normal state faster.

Since polyacrylamide can not be added too much, it needs to be added evenly, evenly and dispersed.

The adding speed should not be too fast, generally about 0.15kg/min, when adding polyacrylamide to the water, some pressure of water should be injected at the adding point, so that it is diluted in time to dissolve, in order to achieve a better dissolution effect.

Polyacrylamide is easily soluble in water, but when its solubility exceeds 10%, it will form a transparent gel in water and lose its fluidity. If a large amount of retention filter aid is added in the dissolution process, a dissolution system with a concentration greater than 10% will be formed in some areas of water, making the dissolution process more difficult to continue.

Therefore, it is necessary to add some amount of water until the stirring blade does not pass, start the blender to circulate the aqueous solution, and then add the polyacrylamide. It is required that the stirring blade should not have edges, otherwise it will produce the adverse effect of polyacrylamide molecular chain suspension and shear, so that the dissolution concentration is not accurate and the dispersion is weakened.

The solution concentration of cationic polyacrylamide is not easy to be too high, generally about 0.5 to 1/1000.

The mixing time of polyacrylamide is not easy to be too long. The mixing time is generally about 60 to 80min, otherwise it will destroy the dispersion effect.

Since the polyacrylamide solution will automatically hydrolyze within 20 to 48 hours, lose viscosity, and then lose dispersibility, it should be used and dissolved in time.

When the amount of polyacrylamide added changes, the dehydration rate of the pulp on the paper machine also changes. The amount of polyacrylamide is adjusted too much, the dehydration is too fast or too slow, which affects the normal and stable production.

Therefore, in the normal production of the paper machine, do not adjust the amount of retention filter aid at will. Anionic or non-ionic polyacrylamide is suitable for long fiber dispersants.