| 摘要 |
PURPOSE:To reduce the required amt. of a calcium compd. and the concn. of fluorine in the waste water in the treatment of waste water contg. fluorine by using a clacium compd. and an inorg. coagulant in combination and reutilizing a part of generated precipitate for the treatment of the feed water. CONSTITUTION:Calcium fluoride is formed by adding an optional calcium compd. selected from Ca(OH)2, CaCl2, CaCO3, etc. in combination with an optional inorg. coagulant selected from an aluminium coagulant such as aluminium sulfate, and iron coagulant such as ferrous sulfate. Further, if the waste water treatment is executed reutilizing at least a part of generated precipitate, the concn. of fluorine in the waste water may be reduced to <=15mg/l by only adding ca. five times weight of the calcium compd. basing on the amt. of F ion in the waste water.
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