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Recycling multi-stage comprehensive treatment method and equipment for fluorine-containing wastewater

A comprehensive treatment and recycling technology, which is applied in the field of multi-level comprehensive treatment of recycling, can solve the problems of incomplete defluorination, low fluorine content, and high difficulty in recycling, and achieve resource recycling, low water content, and easy cleaning Effect

Inactive Publication Date: 2019-07-09
BENGBU COLLEGE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The coagulation and precipitation method is to add coagulant to fluorine-containing wastewater to form colloid and absorb F - , and then through flocculation treatment, the F - However, there are still dissolved fluorine-containing complexes in the water body, and the defluorination is not complete. At the same time, there are still a large amount of suspended matter, organic matter, metal ions and other impurities in the flocs. Low content, difficult to recycle
In addition, the recycling form of fluorine element in fluorine-containing wastewater is mainly calcium fluoride crystals. For example, the patent application number CN201410116814.1 discloses a method for the treatment of fluorine-containing wastewater and the resource utilization of fluorine-containing sludge produced. Reduce fluorine pollution and waste of fluorine resources by converting fluorine-containing wastewater into calcium fluoride and hydrogen fluoride; the patent application number is CN201610463012.7, which discloses the process of recycling fluoride-containing wastewater to produce high-purity artificial fluorite, which is highly efficient in the form of carrier crystallization Extract the fluorine components in wastewater to prepare calcium fluoride artificial fluorite products; the patent application number is CN201610171852.6, which discloses a multi-stage treatment of high-concentration fluorine-containing wastewater in situ to prepare high-purity CaF 2 method, using lime as calcium source, in situ preparation of CaF 2 ; and with MgF 2 Recycling of fluorine in crystal form is rarely reported

Method used

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  • Recycling multi-stage comprehensive treatment method and equipment for fluorine-containing wastewater
  • Recycling multi-stage comprehensive treatment method and equipment for fluorine-containing wastewater

Examples

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Embodiment 1

[0030] A resource-based multistage treatment method for fluorine-containing wastewater, wherein F in the fluoride-containing wastewater - Concentration≧1500mg / L, SS≧600mg / L, COD≧1000mg / L, BOD / COD≦0.1, heavy metal ion concentration≧25mg / L, the heavy metal ion includes Ag + 、Cu 2+ 、Co 3+ 、Ni 3+ ;

[0031] The resource-based multi-level processing method specifically includes the following steps:

[0032] (1) Precipitation and impurity removal: adjust the pH of fluorine-containing wastewater to 5, then add glucono-δ-lactone, optimize the total concentration of heavy metal ions ≦1.5mg / L, and filter to remove sediment;

[0033] (2) Prepare magnesium fluoride with magnesium trisilicate as the crystal nucleus: adjust the pH of the fluorine-containing wastewater filtrate obtained in step (1) to 8, and add magnesium trisilicate with a particle size of 0.01 μm at a dosage of 0.2 g / L, After stirring evenly, add magnesium chloride again, make [Mg2+ ] / [F - ] was 1.2, stirred rapidly ...

Embodiment 2

[0037] Processing method is the same as embodiment 1, difference is:

[0038] (1) Precipitation and impurity removal: adjust the pH of fluorine-containing wastewater to 5.5, and the metal chelating agent used is sodium hexametaphosphate;

[0039] (2) Preparation of magnesium fluoride with magnesium trisilicate as the crystal nucleus: adjust the pH of the fluorine-containing wastewater filtrate obtained in step (1) to 8.5, the particle size of magnesium trisilicate is 0.5 μm, and the dosage is 0.3 g / L, [ Mg 2+ ] / [F - ] was 1.5, stirred rapidly for 5h;

[0040] (3) Biochemical treatment: adjust the pH of the filtrate obtained in step (2) to 6.5, and the dosage of activated sludge is 3g / L;

[0041] (4) Flocculation and impurity removal: The dosage of the composite flocculant is 6g / L.

Embodiment 3

[0043] Processing method is the same as embodiment 1, difference is:

[0044] (1) Precipitation and impurity removal: adjust the pH of fluorine-containing wastewater to 6, and the metal chelating agent used is ethylenediaminetetraacetic acid;

[0045] (2) Preparation of magnesium fluoride with magnesium trisilicate as the crystal nucleus: adjust the pH of the fluorine-containing wastewater filtrate obtained in step (1) to 9, the particle size of magnesium trisilicate is 1 μm, and the dosage is 0.4g / L, [Mg 2+ ] / [F - ] was 1.8, stirred rapidly for 6h;

[0046] (3) Biochemical treatment: adjust the pH of the filtrate obtained in step (2) to 7, and the dosage of activated sludge is 5 / L;

[0047] (4) Flocculation and impurity removal: The dosage of the composite flocculant is 7g / L.

[0048] Adopt embodiment 1-3 method to process fluorine-containing waste water, effluent F - Total concentration≦7.5mg / L, total concentration of heavy metal ions≦1.5mg / L, COD≦100mg / L, BOD / COD≧0.3, S...

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Abstract

The invention discloses a recycling multi-stage comprehensive treatment method and equipment for fluorine-containing wastewater. The method comprises the following steps: (1) adjusting the pH value offluorine-containing wastewater to 5-6, adding a metal chelating agent, and optimizing the total concentration of heavy metal ions to be less than or equal to 1.5 mg / L; (2) adjusting the pH value to 8-9, adding magnesium trisilicate according to an adding amount of 0.2-0.4 g / L, then adding magnesium chloride to enable [Mg<2+>] / [F<->] to be 1.2-1.8, and rapidly carrying out stirring for 3-6 hours to form magnesium fluoride with magnesium trisilicate as a crystal nucleus; (3) carrying out biochemical treatment, namely adjusting the pH value to 6-7, adding activated sludge according to an addingamount of 1-5 g / L, and carrying out continuous aeration treatment at a temperature of 25 DEG C until the concentration of chemical oxygen demand (COD) of the effluent is less than or equal to 100 mg / Land the ratio of biochemical oxygen demand (BOD) to COD is greater than or equal to 0.3; and (4) adding a composite flocculant into the obtained treatment liquid according to an adding amount of 5-7g / L, carrying out standing overnight, and carrying out solid-liquid separation to enable the concentration of F<-> in the effluent to be smaller than or equal to 7.5 mg / L and the concentration of suspended solids (SS) in the effluent to be less than or equal to 150 mg / L. According invention, multistage comprehensive treatment is carried out on the fluorine-containing wastewater through combinationof treatment methods such as a chemical precipitation method, a coagulation precipitation method and a biochemical method, so that the treated wastewater reaches the emission standard, purity of theMgF2 product is improved, and recycling of the fluorine-containing wastewater is realized.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a multi-stage comprehensive treatment method and equipment for recycling fluorine-containing waste water. Background technique [0002] In industry, wastewater discharged from metal smelting, aluminum processing, coking, glass, electronics, electroplating, chemical fertilizers, pesticides and other industries often contains high concentrations of fluoride. For example, the fluorine content in wastewater discharged from glass manufacturing plants reaches 200-2000 mg / L, the fluorine content in the wastewater discharged from chemical plants producing hydrofluoric acid is above 1000mg / L, and the fluorine content in the wastewater discharged from phosphate fertilizer plants reaches 1500mg / L. According to the primary and secondary standards in the national industrial wastewater discharge standard GB8978-1996, the concentration of fluoride ions should be less than ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/14C01F5/28C02F101/14C02F101/20
CPCC01F5/28C02F1/001C02F1/52C02F1/5236C02F1/56C02F1/66C02F3/12C02F9/00C02F2001/007C02F2101/14C02F2101/20C02F2209/08C02F2209/40C02F2301/08
Inventor 胡文娜刘伟
Owner BENGBU COLLEGE
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