Add digested lime milk into the waste liquid until the waste liquid is completely alkaline, and fully stir it, then let it stand overnight and filter it. The filtrate is treated as alkaline waste liquid. This method can not reduce the fluorine content below 8ppm. In order to further reduce the fluorine concentration, anion exchange resin should be used for treatment.
Second, the treatment method of industrial fluorine-containing wastewater
Calcium salt-electrocoagulation-calcium dihydrogen phosphate precipitation technology and related parameters. The electrocoagulation method has good coagulation effect, stability and easy control, and is suitable for treating industrial fluorine-containing wastewater with small water volume. The precipitation of calcium dihydrogen phosphate is * * * precipitation method, and the generated precipitation is CA5 (PO4) 3f ncaf2, which has fast reaction speed and good precipitation effect. This method can be directly used to transform the existing lime precipitation treatment facilities and improve the fluoride removal rate.
Three, fluorine-containing wastewater treatment technology
According to the crystallization theory, we can greatly improve the treatment efficiency of fluorine-containing wastewater by setting prefabricated seed crystals, that is, the so-called raw water subsection injection method (Japanese patent has been applied). Because this method can significantly improve the efficiency of fluoride removal without changing the dosage type and increasing the dosage, it has been continuously applied in the reconstruction of old plants and the construction of new plants (there are more than a dozen applications in Japan). This technology was exhibited at the annual Japan Semiconductor Exhibition.
Four, mine fluoride wastewater treatment method
The invention is suitable for treating wastewater containing solid suspended matter and fluorine. Aluminum salt or aluminate and polymer flocculant are used as polymerization agent, calcium salt is used as auxiliary defluorination agent, and part of solid precipitate is returned to be used as polymerization seed. The control conditions are: adding auxiliary defluorinating agent, aluminum salt or aluminate in turn, adjusting pH to 6-8, adding polymer flocculant after mixing, settling and separating the mixed solid slag from the treated water, and returning part of the precipitate to the raw water to form a continuous circulating treatment process. The two-stage treatment process can be used to treat wastewater with high suspended solids. The medicine source is wide, the dosage is small and the water treatment process time is short.
Five, coal-fired power plant fluoride wastewater treatment method
Coal-fired power plants produce a large number of wastewater with high fluorine concentration and suspended solids (fly ash) exceeding the standard during wet dust removal. If it is directly discharged, it will inevitably pollute the environment and must be treated to meet the requirements of discharge or reuse. Generally, the treatment methods of fluorine-containing wastewater include adsorption method, electrocoagulation method and coagulation precipitation method [1 ~ 3]. Coagulation and sedimentation are the most widely used methods. Fly ash is solid waste discharged from coal-fired power plants. The ash discharge of each 10000kW generator set is about 10000 t, of which 85% is fly ash. At present, the stock of fly ash in China exceeds 400 million tons, and it is increasing at a rate of more than 3 million tons per year. However, the utilization rate of fly ash in China is less than 30%, and there are few reports on the development of PSAA coagulant to treat fluorine-containing wastewater. Using PSAA coagulant developed by fly ash to treat fluorine-containing wastewater from thermal power plant has achieved satisfactory results, and achieved the purpose of treating waste with waste and comprehensively utilizing resources.