Plate and frame filter presses are mechanical devices used for solid-liquid separation of slurries. Due to their good sealing, high filtration pressure, ease of washing, and strong adaptability to different slurries, they are widely used in water treatment, metallurgy, coal washing, food processing, pharmaceuticals, and chemical industries. Today, we will discuss the application of plate and frame filter presses in the aluminum industry:
The aluminum profile production process mainly includes degreasing, alkaline etching, pickling, oxidation, sealing, and coloring of the formed aluminum profiles. The profiles treated in these processes require washing with water, and this wash water, discharged from the cleaning tanks as overflow, is the main source of wastewater in aluminum profile plants. Besides containing a large amount of aluminum ions, the wastewater from aluminum profile plants also contains some zinc, nickel, copper, and other metal ions. The pH of the wastewater varies depending on the production requirements, but it is mostly acidic.
Given that aluminum profile wastewater mainly contains various metal ions and suspended solids, a neutralization and coagulation-precipitation process is used. The wastewater from the workshop flows into a neutralization and equalization tank, where air agitation is used to equalize the water quality. After the wastewater’s quality and quantity are equalized in the equalization tank, alkali is added to adjust the pH, and then it is pumped into the sedimentation tank. Flocculant is added simultaneously during the pumping process. The metal ions in the wastewater react with the alkali to form hydroxides, which then form larger flocs under the action of the flocculant. These flocs quickly settle under gravity. The clear liquid in the upper part of the sedimentation tank can be directly discharged, and the effluent quality meets the discharge standards. The sludge from the sedimentation tank is concentrated in a sludge tank and then pumped into a plate and frame filter press for dewatering before being used for sanitary landfill or comprehensive utilization.
The plate and frame filter press is a filtration device used for solid-liquid separation in industrial production. It is frequently used whenever solid-liquid separation is required in industrial processes. The working principle of the plate and frame filter press is for the separation of solids and liquids. Compared with other solid-liquid separation equipment, the filter cake produced by the filter press has a higher solid content and excellent separation effect. The basic principle of solid-liquid separation is as follows: the mixed liquid flows through a filter medium, the solid particles are retained on the filter cloth, and gradually accumulate on the filter cloth to form a filter cake. The liquid portion, on the other hand, permeates through the filter cloth, becoming a clear liquid free of solids.
