1. Method 1 for treating fluorine-containing waste liquid
Add digested lime milk to the waste liquid until the waste liquid becomes fully alkaline, stir it thoroughly, and leave it overnight. filter. The filtrate is treated as alkali-containing waste liquid. This method cannot reduce the fluorine content below 8ppm. To further reduce the fluorine concentration, anion exchange resin needs to be used for treatment.
II. Industrial fluoride-containing wastewater treatment method 2
This topic is to study the applicable treatment technology of high-fluoride-containing wastewater to limit the emission of fluorine in urban areas. The experiment begins with a pilot study and completes a pilot study. The process technology and related parameters of calcium salt-electrocoagulation and calcium phosphate precipitation methods are proposed.
The coagulation effect of electric coagulation is good, stable and easy to control, and it is suitable for treating industrial fluorine-containing wastewater with small water volume.
Monocalcium phosphate precipitation is a unique precipitation method. The generated precipitate is Ca5(PO4)3F.nCaF2. The reaction speed is fast and the precipitation effect is good.
This method can be directly used to transform existing lime precipitation treatment facilities and improve the fluoride removal rate.
Features of this achievement: the process is relatively simple and easy to implement, and the amount of sediment is small, so it has promotion value.
Experts believe that the research results have reached the domestic advanced level. If promoted, it will prevent fluorine pollution in water bodies and have significant environmental benefits.
3. Fluoride-containing wastewater treatment technology
Features of this technology: 1. Only simple modifications are needed to improve the fluoride removal efficiency of existing equipment. 2. Simultaneous removal of fluorine and phosphorus can also be achieved through simple process modifications. 3. The method is simple and the process is reliable, which can not only improve the treatment efficiency but also reduce the amount of dosage.
Relevant parameters of this system: residence time: 10-60 minutes for seed crystal prefabricated tank; 20-40 minutes for reaction tank. Dosage: fluoride ion concentration 300mg/l calcium ion.
The treatment of fluoride-containing wastewater has problems such as unstable effluent quality, excessive use of chemicals, large amounts of sludge and high moisture content. Especially with the rapid development of the electronic information industry in recent years and the international environmental standard ISO14000 being widely recognized around the world, fundamentally solving the problem of treatment of fluorine-containing wastewater has become represented by large-scale integrated circuits and electronic components such as liquid crystal displays. an important task in the modern electronics industry.
Researchers from the Ecological Environment Research Center of the Chinese Academy of Sciences conducted a systematic and detailed study on conventional lime-based fluoride removal technology while working abroad, and found that the formation of calcium fluoride precipitation is not simply governed by the solubility product. . Experimental results prove that the formation of calcium fluoride precipitation is actually the formation process of calcium fluoride crystals. In the early stage of the reaction, especially when the concentration of raw water is relatively low, whether a sufficient number of seed crystals can be formed determines whether the concentration of calcium fluoride crystals can be formed. The key to the success or failure of fluoride wastewater treatment. Research has found that the efficiency of fluorine-containing wastewater treatment can be greatly improved by setting prefabricated seed crystals according to the crystallization theory, which is the so-called raw water segmented injection method (Japanese patent has been applied for). Since this method can significantly improve the fluoride removal efficiency without changing the type of added drugs or increasing the amount of drugs used, this method has been continuously used in the renovation of old plants and the construction of new plants (there are more than a dozen cases of application in Japan ). The technology was showcased at the annual Japan Semiconductor Exhibition.
IV. Treatment method of mine fluorine-containing wastewater
The treatment method of mine fluorine-containing wastewater is suitable for the treatment of wastewater containing solid suspended solids and fluorine, using aluminum salts or aluminates, The polymer flocculant is used as the aggregation agent, calcium salt is used as the auxiliary fluoride reducing agent, and part of the solid sediment is returned to be used as aggregation seeds. The control conditions are to add auxiliary fluoride-reducing agent, aluminum salt or aluminate in order, adjust pH=6~8, mix well and then add polymer flocculant, mix well and settle to separate the solid residue and treated water, and remove part of the sediment. Return to the original water to form a continuous recycling process. A two-stage treatment process can be used to treat wastewater with high suspended matter content. The source of chemicals is wide, the dosage is small, and the water treatment process takes a short time.
5. Treatment methods for fluorine-containing wastewater from coal-fired power plants
During the wet dust removal process, coal-fired power plants produce a large amount of wastewater with high fluorine concentration and excessive suspended solids (fly ash), such as Direct discharge will inevitably pollute the environment, so it must be treated to meet the requirements for discharge or reuse. The treatment of fluoride-containing wastewater is generally adsorption method, electrocoagulation method and coagulation precipitation method [1~3]. Among them, the coagulation sedimentation method is the most widely used.
Fly ash is a solid waste discharged from thermal power plants using coal as fuel. The amount of ash discharged from every 10,000kW generating unit is about 10,000 tons, of which 85% is fly ash. At present, the amount of fly ash piled up in the country reaches more than 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 our country is less than 30, and it is used to develop PSAA coagulants to treat fluorine-containing Little research has been reported on wastewater. The PSAA coagulant developed from fly ash has achieved ideal results in treating fluorine-containing wastewater from thermal power plants, and has achieved the goals of treating waste with waste and comprehensive utilization of resources.