Method for treating waste alkali liquor generated in organic fluorine chemical industry

Abstract

The invention relates to a method for treating waste lye generated in organic fluorine chemical industry, which comprises the following steps: adjusting the pH value of the waste lye to 3-7 to obtain pH-adjusted waste water; conveying the wastewater subjected to pH regulation into a fluorine removal reaction kettle, adding a calcium agent into the fluorine removal reaction kettle, and reacting for 1-2 hours to obtain turbid liquid; precipitating the turbid liquid, carrying out solid-liquid separation to obtain supernate and solid, enabling the supernate to enter an electrocatalytic oxidation device, carrying out filter pressing on the solid, and returning the solid to the defluorination reaction kettle; carrying out electrocatalytic oxidation reaction in an electrocatalytic oxidation device to change organic fluorine in the supernate into inorganic fluorine, so as to obtain wastewater subjected to electrocatalytic oxidation; and conveying the wastewater subjected to electrocatalytic oxidation to an MVR evaporator, recovering crude salt, and reusing or discharging distilled water. Compared with the prior art, the method integrates and innovates a pH regulation defluorination-electrocatalytic oxidation-MVR organic fluorine production wastewater treatment technology, and solves the problems that fluorine-containing wastewater is difficult to degrade and organic fluoride is easy to scale when directly entering an MVR evaporator for polycondensation.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a method for treating waste alkali liquor generated by organic fluorine chemical industry. Background Art

[0002] Fluoride is one of the essential trace elements for the human body, with an average content of 37 μg·g -1 . Appropriate intake of fluoride is good for the human body. It can participate in the metabolism of calcium and phosphorus to accelerate the formation of apatite in bones and teeth and promote the formation of tooth enamel. Appropriate fluoride can participate in the remineralization of tooth enamel, maintain the health of teeth, and enhance the resistance of teeth to bacteria, thereby reducing the occurrence of caries. Excessive intake of fluoride into the body will not only damage the tooth enamel, but also affect various tissues and organs of the body. Long-term drinking of high-fluoride water will lead to various fluorosis phenomena such as fluorosis, which are mainly manifested as deformation of joints and bone structures, rickets and systemic stiffness until the loss of basic motor functions or even death. Fluoride is also present in other parts of the body, such as plasma, tissues and organs. Excessive fluoride content in these parts will directly affect the nerves and immune system, damage various functions of the body, and eventually cause nervous system lesions. Fluoride poisoning may also have a certain damaging effect on brain tissue. It may cause the following lesions: a decrease in the number of synapses, weakened neuronal connections, and cause intellectual retardation. This symptom even has a certain impact on genetics. When the amount of fluoride in the soil is too high, it will deteriorate the physical and chemical properties of the soil and cause harm to plants.

[0003] With the development of science and technology, more and more compounds contain fluorine. In the synthesis process of these fluorine-containing compounds, a large amount of fluorine-containing organic wastewater is produced. In addition to containing a high content of inorganic fluoride, it often coexists with a large amount of inorganic ions and organic matter. At the same time, it contains a small amount of organic fluoride components, has a high COD value and strong biological toxicity, and has the characteristics of difficult degradation, high toxicity, and poor biochemical properties. The CF bond of organic fluorine compounds in organic fluorine components is highly stable and shows difficult degradation characteristics. The more fluorine substituents a compound has, the more difficult it is to degrade. It is difficult to directly destroy the CF bond by traditional biochemical treatment. The fluorine in this part of wastewater is more difficult to remove using conventional fluorine treatment methods, and when using conventional methods to treat organic wastewater, because it contains a large amount of fluorine ions that corrode equipment, it is urgent to develop a treatment process for alkali containing inorganic fluorine and organic fluorine. With the rapid development of industry, the discharge of fluorine-containing wastewater in my country is bound to increase year by year, which is bound to have an impact on the living environment and endanger human health. Therefore, it is necessary to seek more effective methods to treat fluorine-containing wastewater. In order to solve this problem, scholars from various countries have conducted research on this and developed various fluorine removal technologies. The most commonly used methods include chemical precipitation, coagulation precipitation, ion exchange, membrane separation, adsorption, etc. In the treatment process, inorganic fluorine is relatively easy to treat, while organic fluorine compounds are difficult to treat and difficult to decompose, so they are often treated using electrochemical processes.

[0004] Therefore, the electrochemical oxidation treatment of organic fluorine chemical wastewater has received attention and development in recent years. However, the existing electrochemical processes mostly use titanium-based ruthenium-iridium, iridium-tantalum, platinum and other multi-dimensional coating electrodes. Due to the strong permeability and corrosiveness of fluorides, these electrode coatings are easy to fall off, the service life is extremely short, and they have no engineering application value at all.

[0005] CN110921898 A discloses a method for treating wastewater containing fluorinated aniline compounds, comprising the steps of subjecting the wastewater containing fluorinated aniline compounds to high-temperature Fenton oxidation to convert organic fluorine in the wastewater into inorganic fluorine, and removing the inorganic fluorine in the wastewater. After treatment, the fluorine content of the method is reduced to below 10 ppm, and the COD is reduced to about 2000 mg / L. The process is simple, easy to implement, and highly efficient.

[0006] CN209957615 U discloses an iron-carbon micro-electrolytic cell and an organic-fluorine-containing wastewater treatment system comprising the same. The utility model provides an iron-carbon micro-electrolytic cell and an organic-fluorine-containing wastewater treatment system comprising the same. The iron-carbon micro-electrolytic cell uses micro-electrolytic fillers filled in a filler area to perform micro-electrolytic treatment on organic fluorine in wastewater without power supply, thereby ensuring long-term stable operation of micro-electrolytic treatment of industrial wastewater containing organic fluorine.

[0007] CN219279662 U discloses a comprehensive deep treatment system for wastewater containing organic fluorine, which comprises a chemical reaction zone, a biological reaction zone and a high-efficiency reaction zone connected in sequence. A Fenton fluidized bed is arranged in the chemical reaction zone to effectively degrade organic pollutants such as fluoride in the wastewater.

[0008] CN117105478 A discloses a method for treating wastewater containing organic fluorine, wherein a fluorine ion precipitant, a fluorine ion flocculant or a fluorine ion complexing agent is added to the wastewater containing organic fluorine in advance, and when the organic fluorine wastewater is electrocatalytically oxidized to produce fluorine ions, the fluorine ions react with the added fluorine ion precipitant, fluorine ion flocculant or fluorine ion complexing agent to form a precipitate or complex, thereby reducing the accumulation of fluorine ions and thus reducing the corrosion of fluorine ions on equipment. After the wastewater is treated with electrocatalytic oxidation, the fluorine-containing organic matter can be completely oxidized, and the converted fluorine ions are formed into precipitates or complexes to remove the fluorine ions from the wastewater, thereby achieving the simultaneous and complete removal of organic fluorine and fluorine ions.

[0009] CN118561447 A The invention discloses a ternary electrocatalytic wastewater treatment method, which utilizes photocatalytic oxidation technology to degrade fluorine-containing organic matter. The electrode used is a graphite electrode, and a catalytic filler is added on the basis of electrocatalysis; the catalytic filler uses carbon powder as a base, and the synergistic effect of manganese oxide, ferric oxide and sodium percarbonate makes the prepared catalytic filler have an excellent COD removal rate and ammonia nitrogen removal rate.

[0010] Wang Songyue et al. used electrocatalytic technology to pre-treat wastewater containing organic fluoride, which can reduce COD in wastewater, remove fluorine-organic compounds, and make fluoride ions free in wastewater so that fluoride ions can be effectively removed later. The study found that by changing parameters such as hydraulic retention time, the best treatment parameters are: when the current intensity is stable at 950A, pH = 10-11, and the hydraulic retention time is 800min, the COD removal rate can reach more than 80%.

[0011] The above patents and documents are all used to solve the wastewater problem in the organic fluorine industry from different perspectives. However, as mentioned above, these existing processes often ignore issues such as reaction safety, electrode material corrosion, and the economic efficiency of material recycling. Summary of the invention

[0012] The purpose of the present invention is to provide a method for treating waste alkali liquor produced by organic fluorine chemical industry in order to overcome the defects of the above-mentioned prior art. The method integrates and innovates the pH adjustment defluorination-electrocatalytic oxidation-MVR organic fluorine production wastewater treatment technology, which solves the problem that fluorine-containing wastewater is difficult to degrade and is prone to scaling when directly entering the MVR evaporator.

[0013] The purpose of the present invention can be achieved by the following technical solutions:

[0014] The object of the present invention is to provide a method for treating waste alkali liquor produced by organic fluorine chemical industry, the method comprising the following steps:

[0015] The pH of the waste alkali solution is adjusted to 3-7 to obtain pH-adjusted wastewater;

[0016] The wastewater after pH adjustment is transported to the defluorination reactor, in which a calcium agent is added to remove fluoride ions, and the reaction is carried out for 1 to 2 hours to obtain a suspension;

[0017] The suspended liquid flows into the sedimentation tank by gravity for precipitation, solid-liquid separation, and supernatant and solid are obtained. The supernatant enters the electrocatalytic oxidation device, and the filtrate returns to the defluorination reactor after solid pressure filtration;

[0018] In the electrocatalytic oxidation device, an electrocatalytic oxidation reaction occurs under the action of an electric field, converting the organic fluorine in the supernatant into inorganic fluorine, and obtaining wastewater after electrocatalytic oxidation. As the reaction time changes, the pH will fluctuate between 3-12;

[0019] The wastewater after electrocatalytic oxidation is transported to the MVR evaporator to recover the crude salt and distilled water for reuse or discharge.

[0020] Furthermore, the method specifically comprises the following steps:

[0021] (1) Fluorine chemical production equipment discharges waste alkali liquid into the storage tank;

[0022] (2) The waste alkali liquid in the storage tank is pumped into the pH adjustment tank through a lifting pump to adjust the pH to 3-7 to obtain pH-adjusted wastewater;

[0023] (3) The wastewater after pH adjustment is transported to a defluorination reactor, a calcium agent is added to the defluorination reactor to remove fluoride ions, and the reaction is carried out for 1 to 2 hours to obtain a suspension;

[0024] (4) The suspended liquid in the defluorination reactor is transported to a sedimentation tank for precipitation and solid-liquid separation to obtain a supernatant and a solid, and the supernatant enters an electrocatalytic oxidation device;

[0025] (5) In the electrocatalytic oxidation device, the noble metal and rare metal catalysts in the electrocatalytic oxidation device are fully in contact with the electrocatalytic oxidation electrode plates under the excitation of the electric field to form high-energy hydrated oxygen molecules and generate a large number of hydroxyl free radicals (OH free radicals). The hydroxyl free radicals react with the fluorine-containing organic matter in the supernatant to undergo an electrocatalytic oxidation reaction, converting organic fluorine into inorganic fluorine, thereby obtaining wastewater after electrocatalytic oxidation;

[0026] (6) The wastewater after electrocatalytic oxidation is transported to the MVR evaporator to obtain crude salt and distilled water, and the crude salt is recovered and the distilled water is reused or discharged.

[0027] Furthermore, the solid obtained by solid-liquid separation is filtered through a filter press, and the filtrate is returned to the defluorination reactor.

[0028] Furthermore, the sedimentation tank is a sedimentation tank.

[0029] Furthermore, in step (3), the wastewater after pH adjustment is transported to a defluorination reactor, a calcium agent is added to the defluorination reactor, and the reaction is carried out for 1 to 2 hours to remove inorganic fluorine to below 20 mg / L, thereby obtaining a suspension.

[0030] Furthermore, the waste alkali solution is first pH-adjusted to remove inorganic fluoride ions in the wastewater, and then organic fluorine is degraded to reduce the risk of inorganic fluorine corrosion.

[0031] Furthermore, the alkali liquor is mainly alkali liquor produced by fluororesin, octafluorocyclobutane, tetrafluoroethyl trifluoroethyl ether, tetrafluoroethyl tetrafluoropropyl ether, etc., that is, the waste alkali liquor is one or more of the alkali liquor produced in the production of fluororesin, the alkali liquor produced in the production of hydrofluorocarbons, the alkali liquor produced in the production of octafluorocyclobutane, the alkali liquor produced in the production of tetrafluoroethyl trifluoroethyl ether, and the alkali liquor produced in the production of tetrafluoroethyl tetrafluoropropyl ether.

[0032] Furthermore, the fluorinated organic matter in the waste alkali liquid is a short-chain organic fluorine (such as perfluorooctanoic acid, perfluorooctane sulfonyl compounds, perfluoro and polyfluoroalkyl substances), a super-stable fluoride ion, and the conventional electrode with an oxygen evolution potential of 2.0V cannot open the molecular bonds, making it an extremely difficult to degrade organic matter; even the electrode with an oxygen evolution potential of 2.6V has an extremely slow degradation rate.

[0033] Furthermore, the electrocatalytic oxidation device comprises electrocatalytic oxidation electrode plates and particle electrode fillers, and the particle electrode fillers are filled between the electrocatalytic oxidation electrode plates.

[0034] Furthermore, the particle electrode filler includes a carrier and a precious metal rare metal catalyst, and the precious metal rare metal catalyst is loaded on the carrier; the carrier includes one or more of high-impedance ceramic ring particles, ceramic particles, clay particles, clay particles, etc., and the precious metal rare metal catalyst is selected from one or more of palladium, cobalt, nickel, etc.

[0035] Furthermore, the electrocatalytic oxidation electrode plate adopts titanium substrate coated with titanium oxide, and the catalyst is excited under the action of direct current electric field to generate high-energy hydrated oxygen molecules.

[0036] Furthermore, the electrocatalytic oxidation electrode plate has an electrochemical potential stability window of 5-15V and an electrochemical exchange current density of 1×10 -2 -6×10 -2 mA·cm -2 .

[0037] Furthermore, under the stimulation of the electric field, hydroxyl radicals are released between the electrocatalytic oxidation electrode plates, and indirect oxidation reactions and direct oxidation reactions occur.

[0038] Furthermore, the electrocatalytic oxidation electrode plate adopts a titanium substrate coated with titanium oxide with a purity of more than 99%, and the noble metal rare metal catalyst is in full contact with the electrocatalytic oxidation electrode plate, and is excited to produce high-energy hydrated oxygen molecules under the action of a DC electric field.

[0039] Furthermore, hydroxyl radicals are released and a metastable metal oxide molecule is formed at the corresponding position of the noble metal rare metal catalyst crystallite.

[0040] Furthermore, after 2 to 5 hours of electrocatalytic oxidation reaction, the COD in the wastewater after electrocatalytic oxidation is less than 300 mg / L. That is, the wastewater treated by homogenization pH adjustment - defluorination reaction - precipitation - electrocatalytic oxidation reaches COD less than 300 mg / L, meeting the requirements for entering the MVR evaporator.

[0041] Furthermore, the calcium agent is calcium chloride; the ratio of the calcium agent to the sum of the contents of organic fluorine and fluoride ions in the wastewater after pH adjustment is 3:1, and excess calcium agent is used to remove inorganic fluorine converted from organic fluorine in the subsequent electrocatalytic oxidation process.

[0042] Furthermore, after the filtrate is returned to the defluorination reactor, calcium agent is added.

[0043] Furthermore, after 2 to 5 hours of electrocatalytic oxidation reaction, the COD removal rate in the wastewater after electrocatalytic oxidation is greater than 90%.

[0044] Furthermore, the pH of the waste alkali solution can reach 14 or above, the alkalinity is strong, and the treatment pH range is wide.

[0045] Furthermore, the organic matter in the wastewater can attract the electron cloud on the surface of the noble metal and rare metal catalyst microcrystals, producing an adsorption effect.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1) This technical solution provides a method for treating waste alkali liquor produced by organic fluorine chemical industry, which integrates and innovates pH adjustment defluorination-electrocatalytic oxidation-MVR organic fluorine production wastewater treatment technology, and solves the problem that fluorine-containing wastewater is difficult to degrade and organic fluoride polycondensation is easy to scale when directly entering the MVR evaporator.

[0048] 2) In a method for treating waste alkali liquor produced by organic fluorine chemical industry provided by the technical solution, the wastewater treated by homogenization pH adjustment-defluorination reaction-precipitation-electrocatalytic oxidation reaches COD < 300 mg / L, meeting the requirements for entering the MVR evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention is a schematic flow chart of a method for treating waste alkali liquor generated by organic fluorine chemical industry in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The features such as component models, material names, connection structures, etc. that are not clearly described in this technical solution are all regarded as common technical features disclosed in the prior art.

[0051] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0052] The present invention is further described in detail below in conjunction with specific embodiments.

[0053] In the following examples, the precious metal rare earth catalyst selected is a palladium nickel catalyst, the carrier is a ceramic particle (commercially available), the palladium nickel catalyst is prepared by impregnation, the raw materials are all commercially available, and the preparation method adopts conventional means. The electrocatalytic oxidation electrode plate adopts a titanium substrate, coated with titanium oxide with a purity of more than 99%, the titanium substrate is a commercially available part, and a coating process is used to coat titanium oxide with a purity of more than 99%, and the coating process adopts conventional means.

[0054] Example 1

[0055] This embodiment provides a method for treating waste alkali liquor produced by organic fluorine chemical industry (small-scale test device experiment), referring to Figure 1 , the method comprises the following steps:

[0056] (1) The fluorine chemical production unit discharges 1L of waste alkali liquid (raw water) into the storage tank. The properties of the waste alkali liquid are: strong alkalinity, organic fluorine content reaches 16000mg / L, fluoride ion concentration is 542mg / L, COD 5403mg / L;

[0057] (2) The waste alkali liquid in the storage tank is pumped into the pH adjustment tank through a lift pump, and about 10 mL of concentrated sulfuric acid is added to adjust the pH to 3-4 to obtain wastewater after pH adjustment;

[0058] (3) The wastewater after pH adjustment is transported to a defluorination reactor, and a calcium agent is added to the defluorination reactor to remove fluoride ions. In this embodiment, the added calcium agent is calcium chloride, and the ratio of the added calcium agent to the sum of the content of organic fluorine and fluoride ions in the wastewater after pH adjustment is 3:1. The reaction is carried out for 1.5 hours to obtain a suspension;

[0059] (4) The suspended liquid in the defluorination reactor flows into the sedimentation tank by gravity for precipitation, solid-liquid separation, and supernatant and solid are obtained. The supernatant enters the electrocatalytic oxidation device, and the filtrate returns to the defluorination reactor after solid filter pressing;

[0060] (5) The supernatant is in an electrocatalytic oxidation device, where the noble metal and rare metal catalysts in the electrocatalytic oxidation device form high-energy hydrated oxygen molecules under electric field excitation, and the generated OH free radicals and hydroxyl free radicals undergo electrocatalytic oxidation reaction with the fluorine-containing organic matter in the supernatant, so that the organic fluorine is converted into inorganic fluorine, and wastewater after electrocatalytic oxidation is obtained. Samples are taken for measurement at 120 min, 180 min, 240 min, and 300 min of the electrocatalytic oxidation reaction, and three parallel experiments are conducted to measure the fluoride ion concentration (fluoride content) and COD of the wastewater after electrocatalytic oxidation;

[0061] (6) The wastewater after electrocatalytic oxidation is transported to the MVR evaporator to obtain crude salt and distilled water, and the crude salt is recovered and the distilled water is reused or discharged.

[0062] In this embodiment, the electrocatalytic oxidation device includes electrocatalytic oxidation electrode plates and particle electrode fillers, and the particle electrode fillers are filled between the electrocatalytic oxidation electrode plates.

[0063] Comparative Example 1

[0064] This comparative example provides a method for treating waste alkali liquid generated by organic fluorine chemical industry. The difference between this comparative example and Example 1 is that in this comparative example, in step (2), the pH is not adjusted. In this comparative example, samples are taken and measured at 120 min, 180 min, 240 min, 300 min and 360 min of the electrocatalytic oxidation reaction, respectively, and three parallel experiments are performed.

[0065] Table 1 shows the electrocatalytic experimental conditions and results of Example 1 and Comparative Example 1.

[0066] Table 1 Electrocatalytic test results (in the table, the units of COD and fluoride content (fluoride content refers to fluoride ion concentration) are mg / L)

[0067]

[0068]

[0069] As shown in Table 1, the current is 1.38A, the voltage is 6.72V, and after 300 minutes of electrocatalytic oxidation reaction, the wastewater treated by homogenization pH adjustment-defluorination reaction-precipitation-electrocatalytic oxidation reaches COD < 300mg / L, which meets the requirements of entering the MVR evaporator. In addition, after 300 minutes of electrocatalytic oxidation reaction, the fluorine content in the wastewater treated by electrocatalytic oxidation can be effectively reduced compared with the raw water (waste alkali solution). If the pH is not adjusted, even with a larger current and voltage, the treatment effect is poor.

[0070] Example 2

[0071] This embodiment provides a method for treating waste alkali liquid generated by organic fluorine chemical industry. The difference from Embodiment 1 is that in this embodiment, organic fluorine-containing wastewater generated by a fluorine chemical production enterprise is used as waste alkali liquid (raw water), and the voltage and current applied in the electrocatalytic oxidation reaction are different.

[0072] (1) The raw water quality is as follows:

[0073] Table 2 Example 2 Raw water quality

[0074] Wastewater pH COD(mg / L) Fluoride ion concentration (mg / L) Process wastewater ＞14 2648 510

[0075] (2) Small-scale test device experiment: 1L of water sample was added with about 50mL of concentrated sulfuric acid to adjust the pH to 3-4. The small-scale test device was reacted for 4h, and samples were taken and measured at 10min, 20min, 40min, 60min, 90min, 120min, and 240min of the electrocatalytic oxidation reaction;

[0076] Table 3 Electrocatalytic experimental results of Example 2

[0077]

[0078]

[0079] As shown in Table 3, the COD of the effluent from the pilot device after 4 hours of reaction is 195 mg / L. The current is 9.6A, the voltage is 4.5V, and after 240 minutes of electrocatalytic oxidation reaction, the wastewater treated by homogenization pH adjustment-fluorination reaction-precipitation-electrocatalytic oxidation reaches COD < 300 mg / L, which meets the requirements of entering the MVR evaporator. In addition, using the method of the present invention, after 240 minutes of electrocatalytic oxidation reaction, the fluorine content in the wastewater treated by electrocatalytic oxidation can be effectively reduced by 85.8% compared with the raw water (waste alkali liquor). In addition, the plate area still does not change after 4 hours of reaction, because the waste alkali liquor is first pH-adjusted to remove inorganic fluoride ions in the wastewater, and then degrades organic fluorine, reducing the risk of inorganic fluorine corrosion.

[0080] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for treating waste alkali liquor produced by organic fluorine chemical industry, characterized in that: The method comprises the following steps: The pH of the waste alkali solution is adjusted to 3-7 to obtain pH-adjusted wastewater; The wastewater after pH adjustment is transported to the defluorination reactor, in which a calcium agent is added to remove fluoride ions, and the reaction is carried out for 1 to 2 hours to obtain a suspension; The suspended liquid flows into the sedimentation tank by gravity for precipitation, solid-liquid separation, and supernatant and solid are obtained. The supernatant enters the electrocatalytic oxidation device, and the filtrate returns to the defluorination reactor after solid pressure filtration; In the electrocatalytic oxidation device, an electrocatalytic oxidation reaction occurs under the action of an electric field, so that the organic fluorine in the supernatant is converted into inorganic fluorine, and wastewater after electrocatalytic oxidation is obtained; The wastewater after electrocatalytic oxidation is transported to the MVR evaporator to recover the crude salt and distilled water for reuse or discharge.

2. A method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: The method specifically comprises the following steps: Fluorine chemical production equipment discharges waste alkali liquid into the storage tank; The waste alkali liquid in the storage tank is pumped into the pH adjustment tank through a lifting pump to adjust the pH to 3-7 to obtain pH-adjusted wastewater; The wastewater after pH adjustment is transported to a defluorination reactor, in which a calcium agent is added to remove fluoride ions, and the reaction is carried out for 1 to 2 hours to obtain a suspension; The suspended liquid in the defluorination reactor is transported to the sedimentation tank for precipitation, solid-liquid separation, and supernatant and solid are obtained. The supernatant enters the electrocatalytic oxidation device, the solid goes to the filter press, and the filtrate returns to the defluorination reactor; The supernatant forms high-energy hydrated oxygen molecules in the electrocatalytic oxidation device under the excitation of an electric field, generating hydroxyl free radicals, which react with fluorine-containing organic matter in the supernatant to undergo an electrocatalytic oxidation reaction, converting organic fluorine into inorganic fluorine, thereby obtaining wastewater after electrocatalytic oxidation; The wastewater after electrocatalytic oxidation is transported to the MVR evaporator to obtain crude salt and distilled water, and the crude salt is recovered and the distilled water is reused or discharged.

3. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: The wastewater after pH adjustment is transported to the defluorination reactor, in which a calcium agent is added to react for 1 to 2 hours to remove inorganic fluorine to below 20 mg / L to obtain a suspension.

4. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: The waste alkali liquor is one or more of the alkali liquor produced in the production of fluororesin, the alkali liquor produced in the production of hydrofluorocarbon, the alkali liquor produced in the production of octafluorocyclobutane, the alkali liquor produced in the production of tetrafluoroethyl trifluoroethyl ether, and the alkali liquor produced in the production of tetrafluoroethyl tetrafluoropropyl ether.

5. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: The electrocatalytic oxidation device comprises an electrocatalytic oxidation electrode plate and a particle electrode filler; The particle electrode filler includes a carrier and a noble metal or rare metal catalyst supported on the carrier; The carrier is selected from one or more of porcelain ring particles, ceramic particles, clay particles, and clay particles; The noble metal or rare metal catalyst is selected from one or more of palladium, cobalt and nickel.

6. A method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 5, characterized in that: The electrocatalytic oxidation electrode plate adopts titanium substrate coated with titanium oxide.

7. A method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 6, characterized in that: The electrocatalytic oxidation electrode plate has an electrochemical potential stability window of 5-15V and an electrochemical exchange current density of 1×10 -2 -6×10 -2 mA cm -2 .

8. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: After 2 to 5 hours of electrocatalytic oxidation reaction, the COD in the wastewater after electrocatalytic oxidation is less than 300 mg / L.

9. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: The calcium agent is calcium chloride; The ratio of the calcium agent to the sum of the contents of organic fluorine and fluoride ions in the wastewater after pH adjustment is 3:

1.

10. The method for treating waste alkali liquor generated by organic fluorine chemical industry according to claim 1, characterized in that: After the electrocatalytic oxidation reaction lasts for 2 to 5 hours, the COD removal rate in the wastewater after electrocatalytic oxidation is greater than 90%.

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