PAFC is a kind of inorganic polymer coagulant developed on the basis of coagulation in the mechanism of aluminum and iron salts. Also is a a new type of efficient coagulant based on principles of synergy, joined the elemental iron or iron oxide and other iron-containing compounds. It combines the respective advantages of aluminum and iron salts, for aluminum and iron ions have a significant improvement in form,also polymerization degree increased substantially. Take aluminum and iron coagulants their respective advantages at flotation operations, to improve the performance of PAC coagulation; of high turbidity water and low temperature and turbidity water purification treatment effect was particularly evident, do not add additives or other alkaline coagulant.