Polyaluminum chloride treatment of slightly polluted water situation Now our water resources have been severely polluted and destroyed, our country is a relatively lack of water resources in the country, limited water resources coupled with population growth so that our drinking Water supply is very tight. Due to environmental pollution, many drinking water sources in our country are in a slightly polluted state. With the gradual improvement of water quality standards in our country, micro-polluted water treatment technology has become an important research direction in the field of water treatment. Flocculation method is an important water treatment technology, the type of flocculant, the nature of the decision flocculation effect is good or bad. Polyaluminum chloride is essentially an intermediate product of aluminum ion hydrolysis, polymerization and precipitation reaction, with the characteristics of quick flocculation and good precipitation performance. The removal rate of polyaluminum chloride used in the treatment of slightly polluted water is very high and has a good removal rate Turbidity effect. With the wide application of polyaluminum chloride, its research needs to be deepened. Although the domestic aluminum polyaluminum chloride hydrolysis of ionic form for many years, but still not reached a consensus, still need further study. Due to the complicated morphology of polychlorinated aluminum chloride, the degree of polymerization and the flocculation effect are basically reflected by the basicity of the salt, without considering the effect of the calcium, iron and silicon ions on the calculation of the basicity of the salt, and the ions generally promote the flocculation effect Role, these difficulties need further study. PAC_T industry in the domestic product preparation, the main problems are the following problems. The first point: the purity of the product The second point: the problem of insolubles The third point: the problem of the basicity of the salt The fourth point: the removal of harmful ions such as heavy metals The fifth point: the problem of dosage of hydrochloric acid Polyaluminum chloride is a Efficient water purification agent, can sterilization, deodorization, bleaching, as pure water treatment, drinking water treatment, for tanning, medicine, cosmetics and precision casting and other fields, especially the white aluminum chloride is also available Sizing agent in the papermaking, sugar decolorization clarifier. Food-grade white polyaluminium chloride in the sizing, retention of the slurry, filter aid has also been significantly improved. From the production process point of view: industrial grade PAC, mainly to drum production, product color is tan or yellow. Food grade PAC uses framed filter press technology or spray drying technology. Raw materials used in different processes are also different, which is also an important factor in determining the quality of polyaluminum chloride. The industrial level is supervised by technical supervision, with only the alumina content and the basicity of the salt, the content of water insoluble matter, and the other content is that it is beyond the scope of their regulation to treat industrial effluents. Polyaluminum chloride as a water treatment agent for a variety of water quality adaptability is very strong, especially for high turbidity water coagulation and sedimentation. Purified water better than inorganic coagulants such as aluminum sulfate, water purification costs compared with low 15-30%. Floc formation quickly, settling speed. Containing high alumina, dosage is small, can reduce the cost of making water. PH value of the source water can be condensed in the range of 5.0-9.0. Corrosive, good operating conditions, solubility better than aluminum sulfate. Salt treatment less water, is conducive to ion exchange treatment and water preparation. Adaptability to temperature of source water is superior to that of inorganic coagulant such as aluminum sulfate. The treatment effect on low-temperature water is also better, and the minimum precipitation temperature is -18 ℃.