| Because of the low stability of the high concentration of polyferric chloride flocculant, it's cosmically use is limited. In order to increase the stability, Polyferric Chloride (PFC) coagulation was prepared by titrating sodium hydroxide solution into ferric chloride solution in a very slow speed. Differ proportion of acetic acid, silicic acid and citric acid , phosphate is added to the polysilicic acid—polyferric chloride solutions, Several chemical analysis methods and modern techniques were used to study the characters of PFC coagulation systematically. The influence of basicity (B), the rate of titration and aging time,different basification medicament on the species distribution of PFC were investigated by Fe–ferron complexation timed spectrophotometry. The influence of these anions on the properties of PFC were studied by Fe–ferron complexation timed spectrophotometry, scan electron microscope (SEM), erosion experimentation and traditional jar tests.The experimental results show that basicity, the rate of titration, aging time and anions all can affect the polymerization, species distribution, electrokinetic properties, structure and morphology, coagulating purpose , erosion and stability of PFC. For the first time we attempt to add some citric acid ,can notably improve the coagulate performance and stability of the polyferric chloride flocculant. The PFC whose OH/Fe=1.5, Si/Fe=1, Ac/Fe=0.6 and OH/Fe=1.0,P/Fe=0.12 have very good stability and coagulating performance.
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