Polyaluminum chloride is commonly known as water purifier, also known as polyaluminum chloride, or polyaluminum for short, and its English name is PAC. And basic polyaluminum chloride, spray-dried polyaluminum chloride belong to the same category of water purification agents. It is a kind of cationic inorganic molecular flocculant of polyhydroxy and polynuclear complex. The appearance of solid product is yellow solid powder. Its chemical formula is AL2(OH)nCL6-nm. (In the formula, 1≤n≤5,m≤ 10) It is easy to dissolve in water and has strong bridging adsorption. In the process of hydrolysis, it is accompanied by physical and chemical changes such as electrochemistry, condensation, adsorption and precipitation, and finally forms AL2(OH)3(OH)3, so as to achieve Purification purpose. Spray polyaluminum chloride products are non-toxic, but the aluminum ions contained in them are harmful to the human body. Excessive intake can cause calcium deficiency and damage the brain. It accumulates in the liver, spleen, kidneys and other parts, hindering the body’s digestion and absorption functions.