Fluoride-contained wastewater treatment method and device

Abstract

The invention discloses a fluoride-contained wastewater treatment method. Calcium hydroxide, sodium hydroxide and calcium chloride as well as sodium hydroxide and sodium chloride two-stage chemical precipitation reaction is adopted, meanwhile, PAM (Polyacrylamide) and PAC (Polyaluminum Chloride) flocculating settling is assisted, so that the fluorine concentration of effluent is greatly reduced; after fluoride-contained wastewater is treated by using the method, main pollution factors in the water are within the national normative standard range, and the fluorine ion content is reduced by about 3 times as comparison with the former fluorine ion content; the dosages of sodium hydroxide and calcium chloride and the wastewater treatment cost is greatly reduced. The invention also provides a fluoride-contained wastewater treatment device based on the treatment method. The fluoride-contained wastewater treatment method disclosed by the invention is simple and practical in process and capable of adapting to the changes of water quality and quantity and has a certain flexibility and adjustability; meanwhile, the treatment device is convenient to manage, operate and maintain.

Description

technical field [0001] The invention relates to a treatment method and device applied to high-concentration fluorine-containing wastewater produced in the production process of solar cells. Background technique [0002] With the development of my country's photovoltaic industry, the annual discharge of fluorine-containing wastewater has increased by tens of thousands of cubic meters, resulting in increasingly serious fluorine pollution in the water environment. Due to the great impact of fluorine-containing wastewater on human body and environmental pollution, the fluorine concentration in wastewater has become an important control index in the process of industrial wastewater treatment. Solar crystalline silicon cell manufacturers are facing the problem of how to ensure that the fluorine-containing wastewater generated during production meets the standard discharge and low-cost treatment. [0003] At present, there are many kinds of processes for treating fluorine-containi...

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Problems solved by technology

[0003] At present, there are many kinds of processes for treating fluorine-containing wastewater, including chemical precipitation, flocculation precipitation, adsorption, etc. There are also combinations of chemical precipitation and flocculation precipitation or chemical precipitation, flocculation precipitation and air flotation filtration. Combination of chemical precipitation, flocculation precipitation, air flotation filtration and ion adsorption, such as patent CN102001766B, this method combines the advantages of various treatment methods to continuously treat photovoltaic wastewater containing high concentration of fluoride ions, but increases the air flotation The method and the ion exchange method undoubtedly increase the cost of the equipment. At the same time, the ion exchange method needs to regenerate the resin regularly. In the regeneration process, acid and alkali are needed, and waste liquid will be discharged, causing secondary pollution, and the resin The service life is usually about 3 to 5 years, it needs to be replaced regularly, and the cost of use is high, and the preparation process of "modified double resin" is complicated and costly

The traditional method of combining chemical precipitation and flocculation precipitation to treat fluorine-containing wastewater is to use sodium hydroxide and calcium chloride supplemented with PAC (polyaluminum chloride) and PAM (polyacrylamide) for treatment, and the treatment cost per ton is 24 yuan / ton ,higher cost

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