The Research On Fluorine Removal Of High-fluorine Containing Sewage By Adding Lime And Al₂(SO₄)₃·18H₂O

With the development of modem industry, the production, composition and application of Fluorine and fluoride become more and more wide. Many industries, such as exploitation and processing ore containing fluorine, metal smelting,Al-electrolysis, glass, electroplating, chemical fertilizer, pesticide and chemical industry, produce more and more wastewater which contains high fluorine and fluoride.The fluorine and fluoride are badly polluting envioroment.Especially for ten years, electronics industry, such as color pictuer tude, inetgrated circuit, develops rapidly and the effluent amount of fluorine and flouride is on the increase with each passing day. the pollution of fluorine and fluoride is taken seriously by people of all over the world.Now, the study on treatment technology of the sewage containg fluorine and fluoride becomes important task of the emviromental protection's field. Up to now, there are lots of study on how to remove fluorine from wastewater and there are lots of technology processes on removing fluorine from wastewater. Although the composition of these wastewater are not complex and the F" concentration is not very high (general 100mg/L ~300 mg/L), these fluorine removal technologies have some disadvantage, Such as long process, more kinds of adding medicament and high cost perunit fluorine removal.The research introduce the flourine removal method by adding Lime and Al2(SO4)3.18H2O. The method is simple, stable and remarkble effect.The research finds that the amount of lime, the stirring time and the sediment time affect the result of Fluorine removal in the first stage treatment .In the second stage treatment,the research shows that Al/F ratio, pH influence the result of fluorine removal. The fluorine removal method and the optimal factor are obtained by experiment with the wastewater of production. The optimal factor: First stage treatmentAmount of Lime pH>11.5Reaction time 30minSediment time 60min Second stage treatmentAmount of A12(SO4)3.18H2O Al/F>2.5pH 6-8, optimal pH 6-7Reaction time 5min...