| 摘要 |
PURPOSE:To contrive a stable waste water treatment by adding a Ca salt to the waste water to form and remove Ca fluoride by reaction with fluorine, then adding phosphate thereto to form and remove fluoroapatite by reaction with the residual fluorine and residual Ca salt. CONSTITUTION:The Ca salt (e.g., Ca chloride) is added at a rate of 600-100mg/l in terms of Ca to the waste water to form the Ca fluoride by the reaction with the fluorine, then the precipitate of flocculation is removed to maintain the concn. of the residual Ca salt in the waste water after the treatment at >=200mg/l, more preferably >=600mg/l in the 1st stage of the treatment. The phosphate such as Na phosphate is added at a ratio of about 100-150mg/l in terms of PO4-P to the same waste water to form the fluoroapatite by the reaction with the residual fluorine and residual Ca salt, then the precipitate of flocculation thereof is removed to maintain the concn. of the residual Ca salt in the waste water after the treatment at >=100mg/l, more preferably >=400mg/l. As a result, the fluorine-contg. waste water is stably treated.
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