Treatment method for high-sodium-content fluoride-containing waste water

Abstract

The invention discloses a treatment method for high-sodium-content fluoride-containing waste water. The treatment method comprises the following steps of firstly, preparing fluosilicic acid: adding powdered silica in waste water, and filtering after the reaction is ended, wherein filtrate is fluosilicic acid pretreatment fluid; secondly, flocculating lime: adding calcium hydroxide powder in the fluosilicic acid pretreatment fluid, and controlling the pH value of an end point to be 6 to 9; adding a polyacrylamide flocculant, performing a stirring reaction, then standing and precipitating, and taking out supernate, namely primary effluent; thirdly, performing advanced treatment: adding a deep fluoride removing absorbent, performing a stirring reaction, and then standing and precipitating, wherein the precipitated bottom sludge can be recycled, supernate is secondary effluent, and the concentration of the supernate can reach over 5mg / L. According to the treatment method disclosed by the invention, the problems that lime mud in the high-sodium-content fluoride-containing waste water is difficultly precipitate and the effluent difficultly reaches the standard are solved; the consumption of lime is less, the discharge amount of solid wastes is small, effluent fluoride can be stably reduced to below 5mg / L, and the effluent is discharged after the standard is reached.

Description

technical field [0001] The invention relates to a treatment method for high-sodium fluorine-containing wastewater, in particular to a treatment method for effectively removing fluorine from fluorine-containing wastewater generated in the production process of optical glass. Background technique [0002] When optical glass is processed, due to mechanical damage, there will inevitably be defects such as cracks, slits, and scratches on the surface, and these defects will not only lead to changes in the optical properties of the surface of optical glass materials, but will even cause optical damage. The component is directly damaged. Therefore, in the later stage of optical glass processing, various concentrations of acid and alkali etching are often used to change the surface properties of the material. Commonly used lotions mainly include HF, NaOH, etc., and other H 2 SO 4 、HNO 3 Or ammonia and other aids, the silicon on the glass surface will be converted into H under the...

AI Technical Summary

Problems solved by technology

[0007] In the above existing technologies, fluorine is directly removed by directly adding precipitants containing aluminum, calcium, etc., and the fluorine concentration of the treated effluent can only reach below 10mg / L, which is difficult to meet the requirements below 5mg / L.

If the existing technology is used to treat fluorine-containing wastewater with high concentration of sodium ions in the optical glass industry, the fluorine concentration in the effluent after treatment can only reach about 20mg / L, which is difficult to meet the standard