What is flocculation? Polyaluminium chloride belongs to coagulant? Polymer coagulant dissolved in water, will produce hydrolysis and polycondensation reaction to form a high polymer. The structure of this high polymer is a linear structure with one colloidal particle pulled at one end and another colloidal particle pulled at the other end to act as a bridging bridge between two distant particles that cause the particles to gradually change Large, into a large particle flocs (commonly known as alum flower). Therefore, this adsorption due to the polymer material to bridge the particles to each other bonding process, called flocculation. In other words, flocculation is the addition of high molecular weight substances in water - flocculant, to help the colloidal particles that have been neutralized to further agglomerate, causing them to coagulate into larger flocs more rapidly, thereby accelerating the precipitation. Flocculant is polyacrylamide, polyaluminum chloride is a coagulant, the difference between the simple coagulant is coagulation impurities, coagulant is the settlement. Not a concept, but mostly for sewage treatment. Coagulant: The more typical polyaluminum chloride, the mechanism of action is neutralization, so that smaller suspended particles "Baotuan." Flocculant: Representative for the polyacrylamide (PAM) is a polymer, the mechanism of action is adsorption, bridging, network exclusive, etc., they are usually used in conjunction with the first coagulant poly aluminum, is a small molecule neutralization Baotuan, and then add polyacrylamide, flocculation sedimentation, the role of good. Flocculant: Flocculant in accordance with its chemical composition can be divided into two categories of inorganic flocculants and organic flocculants. Inorganic flocculants which include inorganic flocculant and inorganic polymer flocculant; organic flocculants and synthetic organic flocculants, natural organic polymer flocculants and microbial flocculants. Coagulant: colloidal particles in water and micro-suspended matter aggregation process, can play the role of flocculation and coalescence, coagulant mainly used for drinking water purification and industrial wastewater, special water quality treatment (such as oily wastewater, printing and dyeing papermaking wastewater , Smelting wastewater, radioactive traits, toxic heavy metals such as Pb and Cr, and wastewater containing F, etc.). In fact, coagulant and flocculant no substantial difference, but the general practice of inorganic called coagulant, the organic called flocculant. However, there are some people who divide the flocculants into inorganic polymer flocculants and organic polymer flocculants, inorganic polymer flocculants to polyaluminum chloride, and organic polymer flocculants to polyacrylamide. Because of the nature of polyaluminum chloride, polyaluminium chloride is a coagulant and can also be referred to as a flocculant.