| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a technology capable of recovering fluorine as high-purity calcium fluoride at a high recovery rate without diluting waste water containing fluorine and silicon, that is, even when waste water containing fluorine and silicon is treated while keeping a high concentration. <P>SOLUTION: The waste water containing fluorine and silicon is supplied into a pH adjusting vessel 1 and sodium hydroxide (NaOH) is added, so that sodium silicate is precipitated. Thereafter, the resulting material is supplied to a solid-liquid separation means 2, so that the sodium silicate is solid-liquid separated therefrom. Then, the separated liquid is supplied to a reaction tank 3, water-soluble calcium and a pH adjusting agent are added, and calcium fluoride (CaF<SB>2</SB>) is precipitated (crystallized). <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
