METHOD AND APPARATUS FOR RECOVERING SYNTHETIC FLUORITE

摘要

PROBLEM TO BE SOLVED: To recover fluorine as synthetic fluorite having purity of not less than 97% and an average particle diameter of 5 to 100μm by processing a fluorine-containing waste water containing hydrofluorosilicic acid.

SOLUTION: A recovery method of synthetic fluorite by recovering fluorine as synthetic fluorite from a fluorine-containing waste water containing hydrofluorosilicic acid is disclosed, the method including: a neutralization decomposition step of mixing the fluorine-containing waste water containing hydrofluorosilicic acid with a sodium compound to decompose the hydrofluorosilicic acid to produce silica slurry essentially comprising a mixture of insoluble silica and a sodium fluoride aqueous solution; a separation step of separating the insoluble silica from the silica slurry produced in the neutralization decomposition step to obtain silica-separated water; and a crystallization step of supplying a calcium compound to the silica-separated water to produce calcium fluoride having purity of not less than 97% and an average particle diameter of 5 to 100μm.

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