| 摘要 |
PURPOSE:To redude the addition amt. of a chemical agent required in the treatment of fluorine-containing waste water and the amt. of sludge after treatment. CONSTITUTION:A mixed solution of soluble salts of aluminum and sodium is added to fluorine-containing waste water so that the soluble salts become reaction equivalent with respect to fluorine in waste water to form cryolite (Na3AlF6). Thereafter, cryolite is removed and the waste water containing residual fluorine is made alkaline and calcium soluble salts are added to the waste water in an amt. equal to or more than reaction equivalent with respect to fluorine in the waste water to form calcium fluoride CaF2. By this constitution, the amt. of sludge and the addition amt. of the chemical agents are reduced and fluorine treatment satisfying a discharge standard can be realized. |
