Alumina (AL2O3) content is a measure of the effective content of PACA is correct Alumina (AL2O3) content is a measure of the effective component of PAC PAC is correct PAC flocculant with rapid formation of floc Large particles, good mechanical strength, high sedimentation speed advantages. For high turbidity water, low temperature and low turbidity water, colored water and contaminated water, can achieve good flocculation effect, and the original water ph, temperature, turbidity, alkalinity, organic matter, etc., are more Strong adaptability. Such as organic polymers with high turbidity water treatment, the better. After polyaluminum chloride is added into the water, hydrolysis and polymerization induction occur, and a series of aluminum salt hydrolyzed polymers are formed, which are then removed by flocculation and filtration. The effect is similar to that of aluminum sulfate and ferric chloride. According to toxicity test showed that it is non-toxic, no significant accumulation in animals, teratogenicity and mutagenicity, no carcinogenic risk, use it to clean tap water meet drinking water standards. Due to the high content of AL2O3, the dosage is small, and it is easy to transport, store and use. When it reaches the same flocculation effect, it is calculated by AL2O3 and used for low turbidity water, and its weight is sulfuric acid Aluminum 75% -60%; for high-turbidity water, equivalent to about 20% aluminum sulfate 40%. Its usefulness is less, the advantages of low cost of water purification. Polyaluminium chloride color with the size of the base change. The basicity of the salt is light yellow in the range of 40% -80%, and the shape of the solid polyaluminum chloride varies with the degree of the basic salt. When the basicity of the salt is below 30%, it is crystalline; when it is over 70%, it is not easy to deliquesce. Polyaluminum chloride reacts with alkali to increase its degree of polymerization and the degree of basicity of the salt, resulting in the further formation of aluminum hydroxide precipitates and aluminates. Poly aluminum chloride and aluminum sulfate or other polyvalent salts mixed, easy to produce co-precipitation, reduce or completely lose flocculation performance. Polyaluminium chloride heated to 110 degrees above decomposition occurs, one after another release of hydrogen chloride gas, and finally decomposed into alumina. Aluminum oxide (AL2O3) content is a measure of the effective content of polyaluminum chloride. In general, the greater the relative density, the higher the alumina content. The basicity of the salt is another important quality index of polyaluminum chloride, which is the determinant of the structural morphology, degree of polymerization, flocculation capacity, storage stability and pH value of the product. PH value; compared with other flocculants, polyaluminium chloride in the same concentration of pH value of the highest. Therefore, it is the least corrosive. Viscosity; at the same alumina content, the viscosity of polyaluminum chloride is lower than that of aluminum sulphate, therefore, it is advantageous for transportation and use. Freezing temperature: Poly aluminum chloride precipitation temperature is lower than aluminum sulfate, is conducive to the use and storage of low temperature areas. Filtration performance: In water treatment, polyaluminum chloride treated precipitation than the use of aluminum sulfate turbidity is small, floc large body, so when the filter is generally contained in the surface layer considered, can shorten the flushing time and easy to flush clean. Polyaluminum chloride not only has good flocculation performance, but also when the raw water turbidity increases, the increase of dosage is less than that of ferric chloride, the higher the turbidity, the more significant the difference. As compared with aluminum sulfate, at any turbidity, polyaluminium chloride dosage are less than aluminum sulfate dosage. Polyaluminum chloride can be applied to the treatment of high turbidity water of the Yellow River. In a certain range, the higher the turbidity of raw water, the greater the range of turbidity changes, the more obvious its superiority, so the content of aluminum oxide (AL2O3) is closely related to the active ingredients of polyaluminum chloride.