The invention provides a
crystallization defluorination method for
fluorine-containing
wastewater in the presence of high-concentration
sulfate radicals, and belongs to the technical field of
water treatment.The
crystallization defluorination method comprises the following steps that before defluorination is conducted on
fluorine-containing water containing the high-concentration
sulfate radicals,
lanthanum fluoride crystal seeds, a composite
regulator and a defluorination agent
lanthanum hydroxide are added into the water,
crystallization reaction conditions are controlled, and the
fluorine-containing water containing the high-concentration
sulfate radicals is obtained. Enabling fluorine ions and
lanthanum hydroxide to form a stable fluorine lanthanum compound
crystal through directional crystallization; fluorine lanthanum compound crystals are removed through
solid-liquid separation, and deep fluorine removal of the
water body is achieved. According to the present invention, with the
lanthanum hydroxide crystallization method, by using the extremely low
solubility product of the fluorine lanthanum compound, the efficient fixation of the fluorine ions can still be achieved under the interference of the high-concentration
sulfate radical, the fluorine concentration of the
treated water body is stably reduced to less than 10 mg / L, the secondary
pollution is avoided, and the defects of poor selectivity and easy saturation in the high
sulfate radical environment of the traditional
adsorption method are overcome; the method is suitable for treating high-salt fluorine-containing water bodies such as mining area
wastewater and metallurgical fluorine-containing
wastewater.