Method for producing calcium fluoride by utilizing high-fluorine-content industrial wastewater

Abstract

The invention discloses a method for producing calcium fluoride by utilizing high-fluorine-content industrial wastewater, and belongs to the technical field of fluorine-containing wastewater treatment. The method comprises the following steps: introducing fluorine-containing wastewater into a 1 # reaction tank, adding calcium hydroxide to adjust the pH value to 9-11, stirring for 30 minutes, introducing upper-layer wastewater into a 2 # reaction tank, adding calcium chloride to adjust the chloride ion concentration to 300-400 mg / L, stirring for 30 minutes, introducing the upper-layer wastewater into an inclined plate sedimentation tank, introducing supernate of the inclined plate sedimentation tank into a buffer tank, and filtering to obtain the fluorine-containing wastewater. Sludge generated by the inclined plate sedimentation tank is discharged into a sludge concentration tank; pumping the sludge in the concentration tank into a solid-liquid separator to obtain a mixture solid product with the calcium fluoride content of 30-35% for recycling; and pumping the wastewater in the buffer pool into a precision filter, removing suspended matters in the wastewater, feeding the wastewater into a defluorination filtering tank filled with a special adsorption material, filtering the effluent with the fluoride concentration not higher than 1.5 mg / L, adjusting the pH value of the effluent to 6-9, and discharging the effluent. The problems that in an existing fluorine-containing wastewater treatment technology, material consumption and energy consumption are large, products cannot be recycled, and secondary pollution of different degrees is derived are solved.

Description

technical field [0001] The invention relates to a method for producing calcium fluoride by using high-fluorine-containing industrial waste water, in particular to a method for resource utilization of calcium fluoride used as steelmaking furnace mold slag by cooperating with the treatment of fluorine-containing waste water in the iron and steel industry. Background technique [0002] In recent years, the fluorine chemical industry is one of the fastest growing industries in the chemical industry. With the rapid development of the fluorine chemical industry, the discharge of fluorine-containing wastewater has brought threats to the ecological environment and has become the biggest obstacle to the sustainable development of the industry. Since most of the fluorine element in the treatment of fluorine-containing industrial wastewater eventually enters the sludge, the fluorine content of the sludge is high, and it is easy to cause secondary pollution during storage, transportation...

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Problems solved by technology

[0004] The object of the present invention is to provide a resource utilization method for producing calcium fluoride as steelmaking furnace protective slag by utilizing high fluorine-containing industrial wastewater. By adopting this method, the fluoride ion content in the discharged wastewater can be lower than 1.5 mg / L, and simultaneously produce The steelmaking furnace mold slag raw material with a calcium fluoride content of not less than 30% solves the problem that in the existing fluorine-containing wastewater treatment technology, the material consumption and energy consumption are large, the product cannot be recycled, and secondary pollution of different degrees is derived. Dealing with high cost issues

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