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Defluorination method for fluorine-containing wastewater

A technology for wastewater and calcium fluoride, applied in chemical instruments and methods, water pollutants, water/sewage treatment, etc., to prevent primary nucleation and promote growth

Pending Publication Date: 2021-08-17
SHUI KOU SHAN NONFERROUS METALS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Based on this, it is necessary to provide a method for removing fluoride from fluorine-containing wastewater in view of the technical problems existing in the existing fluoride-containing wastewater defluorination process

Method used

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  • Defluorination method for fluorine-containing wastewater

Examples

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Effect test

Embodiment 1

[0022] 1) Take 500ml of initial rainwater from the lead electrolytic refinery, the wastewater contains 30.74mg / L of F30.74mg / L, add 1ml of superfine CaF2 seed crystal slurry to the fluorine-containing wastewater, and stir for 5min; 2) Add calcium chloride, and the molar ratio of calcium to fluorine is 0.7, the molar ratio of chlorine to fluorine is 1.2, and stir for 30 minutes; 3) Use 5% NaOH solution to adjust the pH of the wastewater to 8.3, and stir for 30 minutes; 4) Add polyacrylamide (PAM) for flocculation reaction, stir slowly for 5 minutes, and then filter and separate . The fluorine removal rate is 98.18%, and the fluorine content of the treated wastewater is 0.56mg / L.

[0023] The innovation of this method compared with similar technologies is to introduce chloride ions on the basis of the traditional calcium salt defluoridation method, so that the solution forms the same ion effect and reduces the solubility of calcium fluoride. Phase primary nucleation can promote...

Embodiment 2

[0025] 1) Take 500ml of initial rainwater from the lead electrolytic refinery, the wastewater contains 32.26mg / L of F32.26mg / L, add 0.5ml of superfine CaF2 seed crystal slurry to the fluorine-containing wastewater, and stir for 8 minutes; 2) Add calcium chloride, the molar ratio of calcium to fluorine 1, the molar ratio of chlorine to fluorine is 1.75, stirring and reacting for 60 minutes; 3) adjusting the pH of wastewater to 8.5 with 5% NaOH solution, stirring and reacting for 30 minutes; 4) adding polyacrylamide (PAM) for flocculation reaction, stirring slowly for 5 minutes and then filtering separate. The fluorine removal rate is 99.02%, and the fluorine content of the treated wastewater is 0.32mg / L.

[0026] The innovation of this method compared with similar technologies is to introduce chloride ions on the basis of the traditional calcium salt defluoridation method, so that the solution forms the same ion effect and reduces the solubility of calcium fluoride. Phase prim...

Embodiment 3

[0028] 1) Take 500ml of initial rainwater from the lead electrolytic refinery, the wastewater contains F15.09mg / L, add 0.25ml of ultra-fine CaF2 seed crystal slurry to the fluorine-containing wastewater, and stir for 10 minutes; 2) Add CaO, the molar ratio of calcium to fluorine is 1 , add NaCl, the molar ratio of chlorine to fluorine is 2.0, and stir for 45 minutes; 3) Use 5% NaOH solution to adjust the pH of the wastewater to 8.7, and stir for 60 minutes; 4) Add polyacrylamide (PAM) for flocculation reaction, and stir slowly for 10 minutes Separated by filtration. The fluorine removal rate is 97.42%, and the fluorine content of the treated wastewater is 0.39mg / L.

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Abstract

The invention discloses a defluorination method for fluorine-containing wastewater, the defluorination method comprises the following steps: S1, adding superfine calcium fluoride seed crystals into the fluorine-containing wastewater, and reacting for 5-10 minutes so that the calcium fluoride seed crystals are uniformly distributed in the wastewater; s2, addign calcium salt and chlorine salt into the wastewater to react for 20-60 min so that fluorine in the wastewater is converted into calcium fluoride; s3, adjusting the pH value of the wastewater to 8-9 by using alkali to precipitate calcium fluoride; s4, adding polyacrylamide into the wastewater for a flocculation reaction, and separating precipitates. The fluorine in the treated wastewater can stably reach a special discharge standard, and meanwhile, the obtained fluorine-removed residue is calcium fluoride with higher purity and can be sold as a product, so that the recycling of fluorine is realized.

Description

technical field [0001] The invention relates to the field of waste water treatment, in particular to a method for removing fluorine from fluorine-containing waste water. Background technique [0002] Fluorosilicate electrolysis is currently used in lead electrolytic refining. The washing of anode slime in the production process will produce fluorine-containing wastewater. Flushing, the initial rainwater contains high fluorine, which exceeds the discharge standard. Fluorine is an essential trace life element for the human body, but excessive fluorine can lead to fluorosis and even bone deformities, so it is very necessary to strictly control the fluorine content in the discharged water. [0003] Existing methods for removing fluoride from wastewater include chemical precipitation, coagulation precipitation, adsorption, ion exchange, membrane separation technology and biological treatment. The existing chemical precipitation method adds a precipitant (calcium salt, phosphate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01F11/22C02F101/14
CPCC02F9/00C01F11/22C02F2101/14C02F1/5281C02F2001/007C02F1/00C02F1/66C02F1/56
Inventor 陈国兰白成庆付高明付绸琳
Owner SHUI KOU SHAN NONFERROUS METALS LTD
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