The large amount of sewage produced by pulping and papermaking in the papermaking industry has become a problem that many countries pay more and more attention to. There are many ways to treat sewage. Commonly used flocculants include polyacrylamide and polyaluminum chloride. Decolorizing flocculants have significant flocculation effects, among which polyacrylamide flocculants are more effective.
Polyacrylamide PAM has excellent flocculation and can be used as a retention and drainage aid in the paper industry and a flocculant for wastewater treatment. Polyacrylamide can be divided into cationic, anionic, nonionic and zwitterionic.
More and more effective is the addition of polymer polyacrylamide flocculants, which can cause the dispersed particles to coagulate through mechanisms such as bridging. In fact, this also plays an important role in the process of sizing, retention and filtration. Various ionic polyacrylamides (PAM) and starch grafted polyacrylamides with high relative molecular mass have remarkable effects in this respect. Cationic polyacrylamide can also play a significant role in sterilization and viscosity reduction when treating papermaking wastewater.
In the "smoke liquid" processing. It is easy to cause fouling during evaporation, which reduces thermal efficiency and is difficult to clean. Intermittent pickling method is adopted, and it needs to be shut down for cleaning. Such as pounding pulp. Surfactant is used as anti-scaling agent in the alkali recovery process of black liquor. It can reduce the viscosity of "black liquor". Reduce scaling and accelerate evaporation. It is composed of sodium polyphosphate. The polymer anti-scaling agent is mainly sodium polyacrylate, Acrylic acid maleic anhydride copolymer salt, etc. The relative molecular weight of this type of polymer anti-scaling agent is low, and it has obvious chelating effect on multivalent metal ions in water and can prevent scaling.