Polyacrylamide (PAM) is a water-soluble polymer linear polymer that is insoluble in most organic solvents and has the advantages of good flocculation performance, low dosage and high efficiency. Polyacrylamide (PAM) is used as a water treatment agent to varying degrees in municipal sewage treatment and industrial wastewater treatment. An example is the treatment of wastewater with polyacrylamide (PAM) in aluminum profile plants, and the production process of aluminum profiles includes degreasing, alkali etching, pickling, oxidation, sealing and coloring, all of which need to be cleaned with water. Aluminum profile cleaning wastewater is discharged in the form of overflow and is the main source of wastewater in aluminum plants. The wastewater produced by aluminum plants contains a large amount of aluminum ions, as well as metal ions such as zinc, nickel, and copper. The pH value of wastewater varies depending on the production requirements, but acidic wastewater is the main focus.
Because the metal ions in aluminum wastewater react with alkali to form insoluble hydroxides, but the particles generated are very small and not easy to settle under the action of water flow, it is necessary to add polyacrylamide (PAM) flocculant to make these particles condense with each other and form large flocculants, which are separated and removed by solid-liquid separation in the sedimentation tank.
Aluminum production wastewater mainly contains various metal ions and suspended solids, which can be treated by neutralizing coagulation. Aluminum production wastewater is discharged from the workshop and enters the neutralization and conditioning tank. The tank is equipped with an air agitator to balance the water quality. After adjusting the wastewater to a balanced water quality, add alkali to adjust the pH value to 6-9, and then pump it into the sedimentation tank, and add polyacrylamide (PAM) during the pumping process. After the metal ions in the wastewater react with the alkali to form hydroxide, under the action of PAM, large particles of alum flowers will be formed, which will settle rapidly under the action of gravity. The clean water on the sedimentation tank can be discharged directly. After the sludge in the sedimentation tank is concentrated by the sludge tank, it is pumped into the filter press for dehydration and used for sanitary landfill or comprehensive utilization.
Due to the types and types of polyacrylamide (PAM), as well as the complexity of aluminum wastewater water quality, different types of polyacrylamide (PAM) are selected for different wastewater water quality. It is necessary to conduct small-scale trials and screenings, followed by on-the-machine trials, to determine the more suitable type and amount of polyacrylamide (PAM).