CN210287057U

CN210287057U - Recycling multistage comprehensive treatment equipment for fluorine-containing wastewater

Info

Publication number: CN210287057U
Application number: CN201920646614.5U
Authority: CN
Inventors: 胡文娜; 刘伟
Original assignee: Bengbu College
Current assignee: Bengbu College
Priority date: 2019-05-07
Filing date: 2019-05-07
Publication date: 2020-04-10
Anticipated expiration: 2029-05-07

Abstract

The utility model discloses a multistage integrated processing equipment of resource of fluoride waste water, include: first sedimentation tank, second sedimentation tank, stirring crystallizer and third sedimentation tank still include pH liquid case, contain magnesium regulating box, activated sludge pond, composite flocculant case and aeration machine and metal chelator case, and this pH liquid case has connected gradually first pump, first solenoid valve through the pipe, communicate between first sedimentation tank, the second sedimentation tank, the stirring crystallizer communicate between second sedimentation tank, the third sedimentation tank respectively, aeration machine and third sedimentation tank intercommunication, the metal chelator case passes through sixth pump and first sedimentation tank intercommunication. The utility model discloses, it is high to have the treatment effeciency, can carry out multistage comprehensive treatment with fluoride waste water, and each part of equipment easily washs moreover, changes the maintenance etc. realizes fluoride waste's resource recycle.

Description

Recycling multistage comprehensive treatment equipment for fluorine-containing wastewater

Technical Field

The invention belongs to the technical field of sewage treatment, and particularly relates to a recycling multistage comprehensive treatment device for fluorine-containing wastewater.

Background

In industry, wastewater discharged from industries such as metal smelting, aluminum processing, coking, glass, electronics, electroplating, chemical fertilizer, pesticide and the like often contains high-concentration fluoride, for example, the fluorine content in wastewater discharged from glass manufacturing plants reaches 200-2000mg/L, the fluorine content in wastewater discharged from chemical plants for producing hydrofluoric acid reaches more than 1000mg/L, and the fluorine content in wastewater discharged from phosphate fertilizer plants reaches 1500 mg/L. According to the first-level and second-level standards in the national industrial wastewater discharge standard GB8978-1996, the concentration of fluorine ions should be less than 10mg/L, and in order to reach the discharge standard, fluorine reduction treatment is required.

At present, the treatment methods of fluorine-containing wastewater at home and abroad mainly comprise a precipitation method, an adsorption method, a reverse osmosis method, a biochemical method, a liquid membrane method, an electrocoagulation method and the like. In consideration of actual operation cost and treatment effect, the precipitation method is the most commonly used defluorination method in industry, and is divided into a chemical precipitation method and a coagulation precipitation method. The chemical precipitation method comprises adjusting pH of fluorine-containing wastewater with appropriate amount of alkali, introducing precipitating agent such as calx, lime milk, calcium salt or other metal salt, and initiating precipitation reaction, wherein the fluorine-containing wastewater also contains other metal ions such as Ag⁺、Cu²⁺、Co³⁺、Ni³⁺Etc. can react with OH in the reaction system^-Coprecipitation occurs, which is not beneficial to the recycling of high-purity fluoride. The coagulating sedimentation method is that coagulant is added into the fluorine-containing wastewater to form colloid and F is adsorbed^-Then flocculating treatment is carried out to F^-The mixed sediment is transferred into flocculate, but the water body still has dissolved fluorine-containing complex, so that defluorination is not thorough, meanwhile, the flocculate also has a large amount of impurities such as suspended matters, organic matters, metal ions and the like, the content of fluorine in the mixed sediment is low, and the recycling difficulty is high. In addition, the recycling form of fluorine elements in the fluorine-containing wastewater is mainly calcium fluoride crystals, for example, patent with application number CN201410116814.1 discloses a method for treating the fluorine-containing wastewater and recycling fluorine-containing sludge generated by the same, which reduces fluorine pollution and waste of fluorine resources by converting the fluorine-containing wastewater into calcium fluoride and hydrogen fluoride; the patent with the application number of CN201610463012.7 discloses a process for preparing high-purity artificial fluorite by recovering fluorine-containing wastewater, and the process is efficient in a mode of carrier crystallizationExtracting fluorine components in the wastewater to prepare a calcium fluoride artificial fluorite product; the patent with the application number of CN201610171852.6 discloses a method for preparing high-purity CaF in situ by multi-stage treatment of high-concentration fluorine-containing wastewater₂The method takes lime as a calcium source to prepare CaF in situ₂(ii) a And MgF₂The crystal form resource recovery of fluorine element is only reported.

In conclusion, the method for multi-stage comprehensive treatment of the fluorine-containing wastewater is provided, so that the contents of metal ions, suspended matters, organic matters and colloid in the wastewater are reduced, and the fluorine ions are recycled to produce high-purity magnesium fluoride, and the method has important significance in the technical field of fluorine-containing wastewater treatment.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a recycling multi-stage comprehensive treatment method and equipment for fluorine-containing wastewater.

The technical scheme of the invention is summarized as follows:

a recycling multi-stage treatment method of fluorine-containing wastewater comprises the following steps:

(1) precipitation and impurity removal: adjusting the pH value of the fluorine-containing wastewater to 5-6, adding a metal chelating agent, optimizing that the total concentration of heavy metal ions is less than or equal to 1.5mg/L, and filtering to remove sediment;

(2) preparation of magnesium fluoride with magnesium trisilicate as crystal nucleus: adjusting the pH value of the fluorine-containing wastewater filtrate obtained in the step (1) to 8-9, adding magnesium trisilicate according to the dosage of 0.2-0.4g/L, stirring uniformly, then adding magnesium chloride to lead [ Mg²⁺]/[F^-]1.2-1.8, rapidly stirring at 500rpm for 3-6h to form magnesium fluoride crystal with magnesium trisilicate as endogenous crystal nucleus, filtering, washing, and drying to obtain high-purity magnesium fluoride;

(3) biochemical treatment: adjusting the pH value of the filtrate obtained in the step (2) to 6-7, adding activated sludge according to the adding amount of 1-5g/L, and continuously aerating at 25 ℃ until the COD of effluent is less than or equal to 100mg/L and the BOD/COD is greater than or equal to 0.3;

(4) flocculation impurity removal: adding the composite flocculant into the treatment liquid obtained in the step (3) according to the dosage of 5-7g/L, standing overnight, and performing solid-liquid separation to obtain effluent F^-The concentration is less than or equal to 7.5mg/L, and the SS is less than or equal to 150 mg/L.

Preferably, the metal chelating agent comprises one or more of glucono-delta-lactone, humic acid, sodium hexametaphosphate, ethylenediaminetetraacetic acid, stearine oxide, sorbitol.

Preferably, F in the fluorine-containing wastewater^-The concentration is not less than 1500mg/L, SS is not less than 600mg/L, COD is not less than 1000mg/L, BOD/COD is not less than 0.1, and the concentration of heavy metal ions is not less than 25mg/L, wherein the heavy metal ions comprise Ag⁺、Cu²⁺、Co³⁺、Ni³⁺。

Preferably, the magnesium trisilicate has a particle size of 0.01 to 1 μm.

Preferably, the purity of the magnesium fluoride is more than 90%, and the particle size is 0.01-0.5 mm.

Preferably, the composite flocculant is composed of chitosan grafted polyacrylamide, polyethyleneimine, polymeric ferric sulfate and polymeric ferric silicate sulfate, and the mass ratio of the components is 2:0.5:1: 1.

The invention also provides a recycling multistage comprehensive treatment device for fluorine-containing wastewater, which comprises: first sedimentation tank, second sedimentation tank, stirring crystallizer and third sedimentation tank still include pH liquid tank, contain magnesium regulating box, activated sludge pond, composite flocculant case and aeration machine and metal chelator case, and this pH liquid tank has connected gradually first pump, first solenoid valve through the pipe, first solenoid valve is connected with first pipeline, second pipeline and third pipeline, wherein: the first pipeline is communicated with the first sedimentation tank, the second pipeline is communicated with the second sedimentation tank, the third pipeline is communicated with the third sedimentation tank, the first sedimentation tank and the second sedimentation tank are communicated with each other, the stirring crystallizer is respectively communicated with the second sedimentation tank and the third sedimentation tank, the magnesium-containing adjusting box is connected with a first conveying pump, the first conveying pump is communicated with the second sedimentation tank through a pipe, the activated sludge tank is connected with a second conveying pump, the second conveying pump is communicated with the third sedimentation tank, the composite flocculant box is connected with a second pump, the second pump is communicated with the third sedimentation tank, the aerator is communicated with the third sedimentation tank, and the metal chelator box is communicated with the first sedimentation tank through a sixth pump.

Preferably, the system further comprises a PLC controller, and the PLC controller is electrically connected with the stirring crystallizer, the aerator, the first pump, the first electromagnetic valve, the first conveying pump, the second pump and the sixth pump.

Preferably, the first sedimentation tank is connected with an input pipe, a valve is arranged on the input pipe, a filter is arranged in the first sedimentation tank, the input end of a pipeline between the first sedimentation tank and the second sedimentation tank is connected to the filter, a third pump and a first flowmeter are sequentially arranged on the pipeline, a fourth pump is arranged on the pipeline between the second sedimentation tank and the stirring crystallizer, a second flowmeter is arranged on the pipeline between the stirring crystallizer and the third sedimentation tank, and the third pump, the first flowmeter, the fourth pump and the second flowmeter are respectively electrically connected with the PLC.

Preferably, a heater is arranged in the third sedimentation tank, the third sedimentation tank is connected with a fifth pump through a pipeline, and the heater and the fifth pump are respectively and electrically connected with the PLC.

Preferably, the filter is a multi-medium filter, and the first solenoid valve is a four-way valve.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention combines the treatment methods of chemical precipitation, coagulating precipitation, biochemical method and the like to carry out multi-stage comprehensive treatment on the fluorine-containing wastewater, realizes the sectional removal or degradation of heavy metal ions, fluorine ions, organic pollutants and suspended matters, and ensures that the treated wastewater reaches the discharge standard.

(2) The method separates out the impurity metal elements in the fluorine-containing wastewater in advance, avoids the coprecipitation of impurity metal ions and hydroxyl in the preparation process of magnesium fluoride, reduces the purity of magnesium fluoride crystals, takes magnesium trisilicate as a growth crystal nucleus of the magnesium fluoride crystals, and has a large number of holes and pore passages communicated with the outside for MgF due to the fact that the magnesium trisilicate structure contains a large number of holes and pore passages communicated with the outside₂The growth speed and growth size of the crystal are specifically controlled.

(3) The method effectively treats the fluorine-containing wastewater, avoids fluorine pollution and fluorine resource waste, produces the magnesium fluoride crystal with high purity and low water content, and can be applied to optical anti-reflection and anti-reflection materials, infrared light polarization materials, catalyst carriers, metal fluxing agents, aluminum electrolysis, window elements and the like.

(4) The recycling multistage comprehensive treatment equipment for the fluorine-containing wastewater has high treatment efficiency, can effectively treat the fluorine-containing wastewater, realizes recycling of the fluorine-containing wastewater, and is easy to clean, replace and maintain various parts of the equipment.

Drawings

FIG. 1 is a schematic view of a recycling multi-stage comprehensive treatment device for fluorine-containing wastewater.

In the figure: 1 a first sedimentation tank, 2 a second sedimentation tank, 3 a stirring crystallizer, 4 a third sedimentation tank, 5 a pH liquid tank, 6 a magnesium-containing adjusting tank, 7 an activated sludge tank, 8 a composite flocculant tank, 9 an aerator, 10 a heater, 11 a fifth pump, 12 a first pump, 13 a first electromagnetic valve, 14 a second pipeline, 15 a third pipeline, 16 a first pipeline, 17 a filter, 18 a third pump, 19 a first flowmeter, 20 a first delivery pump, 21 a fourth pump, 22 a second flowmeter, 23 a second delivery pump, 24 a second pump, 25 an input pipe, 26 valves, 27 a metal chelator tank and 28 a sixth pump.

Detailed Description

The present invention is further described in detail below with reference to examples so that those skilled in the art can practice the invention with reference to the description.

Example 1

Recycling multi-stage treatment method for fluorine-containing wastewater, wherein F in fluorine-containing wastewater^-The concentration is not less than 1500mg/L, SS is not less than 600mg/L, COD is not less than 1000mg/L, BOD/COD is not less than 0.1, and the concentration of heavy metal ions is not less than 25mg/L, wherein the heavy metal ions comprise Ag⁺、Cu²⁺、Co³⁺、Ni³⁺；

The resource multi-stage treatment method specifically comprises the following steps:

(1) precipitation and impurity removal: adjusting the pH value of the fluorine-containing wastewater to 5, adding gluconic acid-delta-lactone, optimizing that the total concentration of heavy metal ions is less than or equal to 1.5mg/L, and filtering to remove sediment;

(2) preparation of magnesium fluoride with magnesium trisilicate as crystal nucleus: adjusting the pH value of the fluorine-containing wastewater filtrate obtained in the step (1) to 8 according to 0.2Adding magnesium trisilicate with particle diameter of 0.01 μm into g/L, stirring, adding magnesium chloride to make [ Mg ]²⁺]/[F^-]1.2, rapidly stirring at the rotating speed of 500rpm for 3 hours to form magnesium fluoride crystals with magnesium trisilicate as endogenous crystal nucleus, and filtering, washing and drying to obtain high-purity magnesium fluoride;

(3) biochemical treatment: adjusting the pH value of the filtrate obtained in the step (2) to 6, adding activated sludge according to the adding amount of 1g/L, and carrying out continuous aeration treatment at 25 ℃ until the COD of effluent is less than or equal to 100mg/L and the BOD/COD is greater than or equal to 0.3;

(4) flocculation impurity removal: mixing chitosan grafted polyacrylamide, polyethyleneimine, polymeric ferric sulfate and polymeric ferric silicate sulfate according to the mass ratio of 2:0.5:1:1 to obtain a composite flocculant, adding the composite flocculant into the treatment solution obtained in the step (3) according to the adding amount of 5g/L, standing overnight, and performing solid-liquid separation to obtain effluent F^-The concentration is less than or equal to 7.5mg/L, and the SS is less than or equal to 150 mg/L.

Example 2

The processing method is different from the example 1 in that:

(1) precipitation and impurity removal: adjusting the pH value of the fluorine-containing wastewater to 5.5, wherein the metal chelating agent is sodium hexametaphosphate;

(2) preparation of magnesium fluoride with magnesium trisilicate as crystal nucleus: adjusting the pH value of the fluorine-containing wastewater filtrate obtained in the step (1) to 8.5, wherein the particle size of the magnesium trisilicate is 0.5 mu m, the dosage is 0.3g/L, [ Mg ]²⁺]/[F^-]Stirring rapidly for 5h under the condition of 1.5;

(3) biochemical treatment: adjusting the pH value of the filtrate obtained in the step (2) to 6.5, wherein the adding amount of activated sludge is 3 g/L;

(4) flocculation impurity removal: the dosage of the composite flocculant is 6 g/L.

Example 3

The processing method is different from the example 1 in that:

(1) precipitation and impurity removal: adjusting the pH value of the fluorine-containing wastewater to 6, wherein the metal chelating agent is ethylenediamine tetraacetic acid;

(2) preparation of magnesium fluoride with magnesium trisilicate as crystal nucleus: adjusting the pH value of the fluorine-containing wastewater filtrate obtained in the step (1) to 9, wherein the particle size of the magnesium trisilicate is 1 mu m, the dosage is 0.4g/L, [ Mg ]²⁺]/[F^-]Stirring rapidly for 6h when the stirring time is 1.8;

(3) biochemical treatment: adjusting the pH value of the filtrate obtained in the step (2) to 7, wherein the adding amount of activated sludge is 5/L;

(4) flocculation impurity removal: the dosage of the composite flocculant is 7 g/L.

Fluorine-containing wastewater treatment by the methods of examples 1 to 3, effluent F^-The total concentration is less than or equal to 7.5mg/L, the total concentration of heavy metal ions is less than or equal to 1.5mg/L, COD is less than or equal to 100mg/L, BOD/COD is not less than 0.3, and SS is less than or equal to 150mg/L, and the method conforms to the sewage discharge standard of GB L, COD (1996).

Referring to fig. 1, the present invention further provides a recycling multi-stage comprehensive treatment apparatus for fluorine-containing wastewater, which is used in the treatment of fluorine-containing wastewater in the above embodiments 1 to 3, and the specific use method thereof is as follows:

firstly, opening a valve 26, sending fluorine-containing wastewater into a first sedimentation tank 1 through an input pipe 25, then controlling a first pump 12 to work by a PLC (programmable logic controller), simultaneously controlling a first pipeline 16 of a first electromagnetic valve 13 to be opened (a second pipeline 14 and a third pipeline 15 are kept in a closed state), opening a sixth pump 28, and controlling a pH liquid in a pH liquid tank 5 so as to control the pH value of the fluorine-containing wastewater in the first sedimentation tank 1 to be 5-6, wherein in order to enable the fluorine-containing wastewater in the first sedimentation tank 1 to optimize the total concentration of heavy metal ions to be less than or equal to 1.5mg/L, simultaneously delivering a metal chelating agent in a metal chelating agent tank 27 into the first sedimentation tank 1, at the moment, sedimentary bottom mud is generated in the first sedimentation tank 1, then controlling a third pump 18 to be opened through the PLC, the fluorine-containing wastewater in the first sedimentation tank 1 to be pumped into a pump 2, the sedimentary bottom mud is filtered in the first sedimentation tank 1 by a filter 17, and then controlling a third pipeline 15 to be, the pH value of the fluorine-containing wastewater filtrate in the second sedimentation tank 2 is 8-9, meanwhile, the flow is detected by a first flow meter 19, a PLC controller controls a first delivery pump 20 to be started, magnesium-containing substances such as magnesium trisilicate and magnesium chloride in a magnesium-containing adjusting tank 6 are added into the second sedimentation tank 2, the magnesium trisilicate is added according to the adding amount of 0.2-0.4g/L through the first flow meter 19, and then the PLC controller turns on a fourth pump 21The fourth pump 21 pumps the mixed liquid in the second sedimentation tank 2 into the stirring crystallizer 3, magnesium fluoride crystals with magnesium trisilicate as endogenous crystal nuclei are formed under the action of the stirring crystallizer 3, then the magnesium fluoride crystals are filtered, washed and dried to obtain high-purity magnesium fluoride, the mother liquid removed from the stirring crystallizer 3 is sent into the third sedimentation tank 4, the PLC controller controls the conduction of the second pipeline 14 to ensure that the pH liquid enters the third sedimentation tank 4, the pH value of the solution in the third sedimentation tank 4 is 6-7, meanwhile, the PLC controls the continuous aeration treatment at 25 ℃ by the control heater 10 to ensure that the COD of the effluent is less than or equal to 100mg/L and the COD/COD is less than or equal to 0.3, and then the flow data is detected according to the second flow meter 22, the PLC controls the second pump 24 on the composite flocculant box 8 to be opened, the composite flocculant in the composite flocculant box 8 is put into the third sedimentation tank 4, then the mixture is stood overnight, and the fifth pump 11 is controlled to carry out solid-liquid separation to lead the effluent F^-The concentration is less than or equal to 7.5mg/L, and the SS is less than or equal to 150 mg/L.

In the invention, PLC control adopts Siemens S7-700 or S7-1200 to carry out logic control, so that the equipment can open or control each part connected with the equipment according to a work flow sequence, the pH value of the pH liquid in the pH liquid box 5 is configured according to the need of regulating the pH value of the fluorine-containing wastewater, the equipment can be operated and used intermittently when in use, for example, after the fluorine-containing wastewater entering the first sedimentation tank 1 from the input pipe 25 is treated in the third sedimentation tank 24, the equipment is cleaned and maintained, one end of time is isolated, and then the next round of use is carried out, or the fluorine-containing wastewater can be directly used in the next round after being pumped out from the third sedimentation tank 24, and the equipment is shut down for unified maintenance or cleaning after several rounds, and is reused after the treatment; the first electromagnetic valve 13 adopts a four-way valve, the filter adopts a multi-medium filter, the specifications are various, such as 5 mu, 10 mu, 20 mu, 55 mu, 100 mu, 130 mu, 200 mu and the like, a user can select filter discs with different accuracies according to the requirement of water use, the valve 26 can adopt a two-position two-way electromagnetic valve controlled by a PCL controller, or a manual valve, except that a sludge pump is adopted as the second delivery pump 23 for pumping the activated sludge in the activated sludge tank into the third sedimentation tank, other pumps such as the first pump 12 to the sixth pump 28 can adopt common pumps, and of course, other types of pumps which are sold in the market and have pumping functions can be selected according to the actual requirements of the user.

While embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments, which are fully applicable in all kinds of fields of application of the invention, and further modifications may readily be effected by those skilled in the art, so that the invention is not limited to the specific details without departing from the general concept defined by the claims and the scope of equivalents.

Claims

1. A multi-stage comprehensive treatment equipment for recycling fluorine-containing wastewater is characterized by comprising: first sedimentation tank (1), second sedimentation tank (2), stirring crystallizer (3) and third sedimentation tank (4), still include pH liquid case (5), contain magnesium regulating box (6), activated sludge pond (7), composite flocculant case (8) and aeration machine (9) and metal chelator case (27), this pH liquid case (5) has connected gradually first pump (12), first solenoid valve (13) through the pipe, first solenoid valve (13) are connected with first pipeline (16), second pipeline (14) and third pipeline (15), wherein: the first pipeline (16) is communicated with the first sedimentation tank (1), the second pipeline (14) is communicated with the second sedimentation tank (2), the third pipeline (15) is communicated with the third sedimentation tank (4), the first sedimentation tank (1) and the second sedimentation tank (2) are communicated, the stirring crystallizer (3) is respectively communicated with the second sedimentation tank (2) and the third sedimentation tank (4), the magnesium-containing regulating box (6) is connected with a first conveying pump (20), the first conveying pump (20) is communicated with the second sedimentation tank (2) through a pipe, the activated sludge tank (7) is connected with a second conveying pump (23), the second conveying pump (23) is communicated with the third sedimentation tank (4), the composite flocculant box (8) is connected with a second pump (24), the second pump (24) is communicated with the third sedimentation tank (4), and the aerator (9) is communicated with the third sedimentation tank (4), the metal chelating agent box (27) is communicated with the first sedimentation tank (1) through a sixth pump (28).

2. The recycling multistage comprehensive treatment equipment for fluorine-containing wastewater according to claim 1, further comprising a PLC controller, wherein the PLC controller is electrically connected with the stirring crystallizer (3), the aerator (9), the first pump (12), the first electromagnetic valve (13), the first delivery pump (20), the second delivery pump (23), the second pump (24) and the sixth pump (28).

3. The multistage comprehensive treatment equipment for recycling fluorine-containing wastewater according to claim 2, wherein the first sedimentation tank (1) is connected with an input pipe (25), the input pipe (25) is provided with a valve (26), the first sedimentation tank (1) is internally provided with a filter (17), the input end of a pipeline between the first sedimentation tank (1) and the second sedimentation tank (2) is connected to the filter (17), a third pump (18) and a first flowmeter (19) are sequentially arranged on the pipeline, a fourth pump (21) is arranged on the pipeline between the second sedimentation tank (2) and the stirring crystallizer (3), a second flowmeter (22) is arranged on the pipeline between the stirring crystallizer (3) and the third sedimentation tank (4), the third pump (18), the first flowmeter (19), the fourth pump (21) and the second flowmeter (22) are respectively electrically connected with the PLC.

4. The multistage comprehensive treatment equipment for recycling fluorine-containing wastewater according to claim 2, wherein a heater (10) is arranged in the third sedimentation tank (4), the third sedimentation tank (4) is connected with a fifth pump (11) through a pipeline, and the heater (10) and the fifth pump (11) are respectively electrically connected with a PLC controller.

5. A multi-stage comprehensive resource treatment device for fluorine-containing wastewater according to claim 3, wherein the filter (17) is a multi-media filter, and the first electromagnetic valve (13) is a four-way valve.