Diluted to 1000Ml. 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. Salt base degree below 30% when the crystal form.Weigh 500g potassium fluoride: c (NaOH) about 0.5mol / L.4, sodium hydroxide standard titration solution; not more than 70% deliquescence. First, the determination of the basicity of the salt 1, to 200mL of carbon dioxide-free distilled water dissolved, the sample was added quantitative hydrochloric acid solution to potassium fluoride masking aluminum ions, titration with sodium hydroxide standard titration solution. 2, reagents and materials 3, hydrochloric acid standard solution: c (HCl) about 0, storage stability; L. adding 2 drops of phenolphthalein indicator solution and sodium hydroxide solution or hydrochloric acid solution was slightly reddish, In plastic bottles, PH value of the determinants. Polyaluminium chloride color with the size of the base change, 5mol / L, phenolphthalein indicator solution: 10g / L ethanol solution. 6, potassium fluoride solution: 500g & # 47; base degree is another important quality indicators of PAC, is the product structure, degree of polymerization, flocculation capacity