Polyaluminium chloride code PAC, usually also called water purifier or flocculating agent, it is between ALCL3 and AL (OH) 3 of a kind of water-soluble inorganic polymer, chemical general formula for [AL2 (OH) NCL6 - while NLm] which m on behalf of the polymerization degree, neutral degree n PAC products.Color yellow or pale yellow, dark brown, dark gray resin solid.Bridging the product has strong adsorption performance, in the process of hydrolysis, accompanied by condensation, adsorption and precipitation and other physical and chemical process.Polyaluminium chloride and the traditional inorganic coagulants the fundamental difference between the traditional inorganic coagulants as low molecular crystal salt, and the structure of polymeric aluminium chloride from morphological and changeable multiple carboxyl complex composition, flocculating settling speed, suitable for wide PH range, no corrosive to the pipeline equipment, water purification effect is obvious, to be effective in the removal of water color quality SS, COD, BOD and arsenic, mercury and other heavy metal ions, the products are widely used in drinking water, industrial water and wastewater treatment field.