Polyaluminum chloride is an inorganic polymer coagulant, also called polyaluminum for short. It is widely used in the purification of domestic sewage and industrial wastewater, the purification of low-temperature and low-turbidity water, the recycling of ash-washing wastewater from papermaking, petrochemical and thermal power plants, and the decolorization and purification of COD, BOD and SS from printing and dyeing, wool spinning and wastewater. It has the advantages of fast floc formation and sedimentation, higher treatment capacity than traditional products such as aluminum sulfate, less corrosiveness, better operating conditions, better solubility than aluminum sulfate, and better adaptability to source water temperature than inorganic coagulants such as aluminum sulfate.