Polyaluminum chloride used in cooling water flocculation PAC polyaluminium chloride is a new type of highly effective water purifying agent, which has a wide range of aluminum salt flocculant water treatment, the role of oil removal, corrosion of the equipment pipeline is small , And also has the characteristics of rapid settling of iron salt flocculant, easy separation, low temperature water treatment performance, wide PH scale of water treatment and so on. After different methods to prepare polymerized aluminum chloride crystals, XRD and other analytical methods Characterization, to explore a different solution of poly aluminum ferric chloride production conditions. 20 Practice The successful development of polyaluminum chloride since the 1970s has provided a broad perspective for the development of inorganic polymer water purifiers and is rapidly used in the water industry. However, the true use of polyaluminium chlorides for water practice The shortcomings, such as small flocs, and fragile, small flocs through the filter into the filter, reducing the water quality, small sedimentation slow sedimentation. Poly aluminum chloride manufacturers of polycrystalline iron production methods and conditions of several contrastive study, in order to enhance the stability of the product and coagulation, based on experimental results put forward feasible ways. Different degree of alkalinity of PAC, the system of coke wastewater coagulation test to explore the best coking wastewater treatment process of alkalinity, dosage and scale of the scale of application, together with the degree of alkalinity and pH on the impact of residual aluminum Also conducted a discussion. The residual aluminum in PAC decreased with the increase of pH. When the pH was neutral, the residual amount of aluminum in the water was the least. With the increase of pH, the residual amount of aluminum was added. Alkalinity affects the speciation of aluminum. The results show that when the degree of alkalization is 1.5, the residual aluminum content in water is the lowest. After comparing the effect of alkalinity on COD removal and the residual aluminum content in water, it is found that the more the COD decreases, the less the residual aluminum content in the water, and the trend of the two changes is very common.