TW200304428A - Method and apparatus for treating fluoro-containing water discharge - Google Patents

Abstract

The present invention obtains a filtration cake containing a high purity of CaF2 from a water discharge containing a small amount of fluorine. The invented method comprises: a step of concentrating a fluoro-containing discharge; a step of adding a calcium compound into the concentrated water discharge and undergoing a reaction; and a step of applying a solid-liquid separation on the reaction formation obtained in the previous step.

Description

200304428

TECHNICAL FIELD The present invention relates to a method and a device for obtaining a semiconductor system. The prior art is used in the process for various kinds of cements containing salt and so on. After the implementation of the method, the fluorine that can be obtained should be as follows: Ca2 + + This is strictly strict. This drainage is expected to be good. Therefore, compounds such as fluorine are discharged by a fluorine-containing wastewater treatment technology, and are particularly discharged. Treatment technology for fluorine-containing drainage. The treatment methods for high-purity calcium fluoride-containing wastewater include various types of i-containing wastewater discharged from the semi-V body ‘Chengde’, including treated water such as the exhaust gas containing fluorine. In this kind of drainage, the amount of 纟 is very small and is discharged in large quantities. Finally, calcium compounds are added to generate a foulant containing CaFg (precipitate). This method is used for solid-liquid separation of this sludge. If this way = fluorine is discharged from the water system as the solid content of Cat, and the treated water can be reduced. In this method, the generation of Cah is shown in trans form. + 2F — CaF2! In terms of treatment of 3 fluorine drainage, in recent years, the standard for the drainage of fluorine has also demanded effective recovery of fluorine. In addition, since a large amount of Si component is contained, there are difficulties in handling, and it is desired to properly process the Si component. It is also apparent from the above formula that the excessive addition of water-soluble calcium gradually increases. In recent years, it has been desired to obtain treated water having a further reduced fluorine concentration. Japanese Patent Application Laid-Open No. 2 0 0 1 — 2 1 2 5 7 4 discloses that it is a kind of insoluble salt that inhibits the production of Ca {? 2 by treating ions that are not contained in water

200304428 Description of the invention (2) The amount of ions σ w, and f of the ions is increased, therefore; r 疋 疋 ′ is based on the amount of such ions to control the salt. 1 1 4382 For sludge circulation, a part of w Ϊ 2 7 sludge is sent back to the reaction tank, and the defluorination efficiency from ^ drainage. The concentration is disclosed as No. 31〇: =-2374851: a technique for adjusting Shi Xi in the drainage to 2 or less. -The problem to be solved by the invention: sex salt = sub: if is not suitable for containing a relatively large amount of insoluble treatment liquid, but for a concentration that does not contain a large amount of such ions, ^ +. Furthermore, it is possible to reduce the possibility that the fluoride ion insoluble salt in the treated water is contained in the filter cake containing caF2. Add processing equipment. The reaction product of horse's mouth body composition, which needs large-scale and the latter ancient and i γ need to return a large amount of :; Although it is effective in promoting the precipitation of C 吒 ', the clay in Γ Γ, therefore, The solid components other than the obtained CaF2-containing filter were also concentrated. y means, ’According to these methods, although the treatment with reduced fluorine concentration can be obtained 7: You people have difficulty in getting the high-purity caF-containing filter cake. ^: The aerosol system drainage discharged from the exhaust treatment step is due to the fact that the gas: ,,, low> agriculturality but a large amount of emissions, so C_aF ^ formed from such low-concentration fluorine drainage is also expected to be recovered. In addition, such a wastewater contains an Si-containing component ', which must be removed in order to recover high-purity CaF2.

2042-5521-PF (Nl) .ptd Page 10, 200304428 V. Description of the invention (3)-The purpose of the invention is to provide a method for concentrating fluorine based on wastewater containing a small amount of fluorine to effectively use the treated water while being able to Fluorine-containing drainage treatment technology that achieves effective drainage treatment in the latter stage. Furthermore, the object is to provide an effective technique for removing Si components. Furthermore, & provides a drainage treatment technology that can reduce the size of the processing equipment in the subsequent stage and obtain CaFz-containing filter cake with high purity of Cai? 2. Means to solve the problem: The present inventors studied the processing before supplying the gas-containing drainage water to the reaction step, and found the following method. That is, according to the present invention, the following methods are provided. ("-A method for treating waste water containing waste water, the method includes: a step of condensing the drain water, a step of returning the treated water produced by the concentration step to the drainage source, and a process of the concentration step The step of measuring the concentration of a predetermined component of the two liquids. "5 (2) The method described in the above" is used to implement the method described in (2). Wherein, the above-mentioned concentration step 2 includes the following gas-containing drainage or the gas-containing gas adjusted to the pH of the range: water: (4) as described in (3), depending on the above-mentioned drainage-containing P Η (5) as described in (4) (6) The method after the aforementioned concentration step according to (5), wherein in the aforementioned 'for the case of empirical method', HF is used as the method, and as the pretreatment solution. Before the concentration step, monitor, then Add an acidifying agent. It is the aforementioned acidifying agent. The HF system of the acidifying agent is

2042-5521-PF (Nl) .ptd Page 11, 200304428, Description of the invention (4) (7) As described in any of (1) to (6), the square fluorine drainage system Harm treatment ★ Seven harvest a ^. Drain water or scrubber. & Λ handle & A ~ (7), wherein the reaction obtained by encapsulating η ions in concentrated drainage * to generate CaF2, the reaction obtained from the reaction step 2 2 ί Ϊ The product is subjected to a solid-liquid separation step of solid-liquid separation. ^ u π kinds of government installations, which are treatment devices for fluorine-containing wastewater, including: ρ Η monitoring device for fluorine-containing wastewater, # 4_ & a ^ ^. ϋ M ^ ^ ^ ^ Device for supplying acidifying agent for S-fluorine drainage , Electricity to the pipeline of the water source, analysis device, and return of treated water to the drain

(1 0) Another example is (9); ten, M, Z, and W. Analysis of the electrical parameters of the second after the analysis of 'there is equipped with the above-mentioned electroosmotic fluorine-containing drainage device rat treatment liquid as the aforementioned acidifying agent, Supply to the step; St ^ t drainage treatment method is implemented, then the concentration step drainage treatment. In addition, Weilu ’s degree can effectively reuse the fresh water in the later stage. Inflow + water returns to the source of drainage, and it can be carried out, and at the same time, it can also recover the fluorine component by supplying the concentrated liquid. Implementation mode: Enough, the current fluorine is highly recovered. The implementation of the present invention will be described in detail below. The concentration step, the method of this concentration step, includes a step of adding fluorine-containing wastewater as a source, and a concentration from the + step that measures the concentration of the treated water returned from the needle and the step to the drainage product.之 之 既 ^ 〇

200304428 V. Description of the invention (5) (Fluorine-containing drainage) The treatment method and device of the present invention, that is, the treatment technology department, can be applied to wastewater treatment containing fluorine. The fluorine-containing drainage can be applied to the fluorine-containing drainage discharged from semiconductor processes such as Shi Xijingyuan, printed circuit board processes, stainless steel plate processes, and hydrofluoric acid processes. In particular, the treatment technology of the present invention can be ideally applied to the fluorine-containing wastewater generated by the semiconductor process. In particular, it is applicable to the gas generated from the detoxification steps such as the thermal decomposition of various fluorine-containing gases used for the film formation steps of semiconductor processes (accumulation gas, cleaning gas, dry etching gas, etc.), and is suitable for this purpose Treatment of fluorine-containing drainage generated by the gas washing step. When the thermally decomposed gas is washed by a scrubber or the like, washing water in which hydrofluoric acid or the like is dissolved is generated. Suitable for use in this washing water. For example, it is suitable for fluorine-containing wastewater having a fluorine concentration of 500 mg / 1 or less, more preferably 200 mg / 1 or less, and more preferably 30 mg / l or less. In addition, it can be applied well even when silicon (S i) is also contained. Hereinafter, the processing technique of the present invention will be described with reference to FIG. 1. In Fig. 1 "Although it is a treatment of a water containing M from a sourizer system or an exhaust gas detoxification device", it is applicable to the present invention for explanation. (PH monitoring or adjustment steps for fluorine-containing drainage) In the semiconductor manufacturing process, generally used gas-based gas, in general, J is a "sex-rolled body", but the scrubber system is discharged after the scrubber treatment The drainage may be made alkaline by adding alkali to the pipeline. The drainage discharged during the semiconductor process is in the form of hexafluorosilicic acid ion (siF2_).

2042-5521-PF (Nl) .ptd Page 13 200304428 V. Description of the invention (6) contains fluorine and silicon, but the drainage is acidic, or the fluorine is released based on acidification (refer to the following reaction formula). The chaotic ion ^ ^ + 2 H2 〇 < = > Si〇2 + 6H + + 6F ~ In particular, in the case of using an electrodialysis device to concentrate, if the I ion system is in a state that is easy to be released under acidic condition, it can be effective Roll down. Therefore, especially in the case where an electrodialysis device is used to perform the concentration step, it is preferable to adjust the fluorine and silicon-containing drainage to the acidic side. The range of pH 2 to 6 is preferred. Therefore, the fluorine-containing (silicon-containing case) drainage system is originally adjusted to a pH range of 2 to 6 or less. For pH adjustment, in addition to various inorganic acids such as sulfuric acid, although acids such as organic acids can be used as the acidifying agent, HF is preferably used. If it is M, it can be recovered as CaF2 in the subsequent reaction step, and the resulting two can avoid an increase in the amount of impurities. By using a concentration step, a portion of the fluorine / Chen liquid is returned to the ρ Η adjusting tank for use. It is more suitable for seeding, and it does not require the supply of an acidifying agent, and it can be inhibited from changing. The fluorine concentration in the fluorine concentrated solution found after Γ depends on it, and HF can also be supplied as an acidifier. The pH adjustment system, for example, at the 1st place of the 1st day of the year (see the minister) birch ?, 1, the fluorine-containing drainage can be introduced into the adjustment f set 4, Dli for continuous application. The pH adjustment tank 2 has an acidifier supply Supply device 8. It also has a fluorine concentrate and under-supply agent produced in the subsequent stage. Any of the device 4 and the fluorine concentrate supply device 8 are provided.

200304428 V. Description of the invention (7) and the control device 'detected by using the PH detection device 6 The supply amount is controlled. Xiao You again (not shown), in Figure i, t, filtering, filtering, etc. are prepared in advance, and the filter device, which is the appropriate step for preparing and entering, is 10 per device. With proper steps to deal with inconvenient ocean swims, it is possible to solve the problem by using a suitable purging device after the subsequent step of passing the gas-containing exhaust step (concentration step c excludes solid components or floating matter, so it is better. Concentration step is 楹古 入 # The concentration of the fluorine concentration in the concentrated cyanogen drainage in the concentration step. As a method that can be used to increase the concentration of fluorine;, =, although various conventional devices can be used, but the seeds) or its salts are not: Material = remove possible coexisting metals (better. For example, use = (can be desalted or refined) < device is sufficient to separate and remove silicon based human :: device. #Using an electrodialysis device, can shrink the device 12, The impure substance is shown. In FIG. 1, the method of “dialysis as an electrodialysis zone” is used as an electrodialysis device. It is set up. Furthermore, it is possible to use an electrodialysis surface using an ion exchange membrane, which is generally a ^ wtK object Impurities in the semiconductor process side of the electrodialysis device φ 丄 anion membrane, F-, Sip2, H +, F_, M2- in the drainage penetrated through. For ionization; "moved to the concentrate side" and ^ 〇2 on The direct penetration varies, so the membrane penetration of the membrane The degree is based on the difference of ions. «Migration, Quyou 1㈢ adjust the processing flow rate, and can adjust the concentration of other ions in the permeate. 2042-5521-PF (Nl) .Ptd page 15200304428 5. Description of the invention (8) The fluorine-containing drainage system concentrated by the concentration device 12 is preferably stored in a storage tank 20 after removing the floating matter by a filtering device 14 or the like. In a tank 20, a device 22 for detecting the fluorine concentration of the concentrated liquid is provided. For the better, the daily or frequent detection of fluorine concentration is better. Although the fluorine concentration can be about 5 ^ Jmf 〇 ~ 10000mg / 1 in the concentration step, it is actually within the range of 500 mg / 1 or less. : ,,, and better; Chen Bei 5 to fluorine concentration more than 5 000 mg / 1, Bei Ji J from the cost and dry: = seems to be a little sleepy, and, after implementation '. Gu It is easy to add an excessive amount of calcium compound, so it is difficult to obtain the high purity mesh erythritol and the reaction steps can be made into multiple stages as needed. 3 000 軚 / 1 or less' nn. Also, the fluorine concentration is preferably 50 mg / l or more If it is less than ιοο = ,, it is difficult to effectively generate the name in the reaction step. It is more preferable to store two i 3. In addition, when it is necessary to further concentrate, carry out "哝" to feed the concentrated liquid to the concentration device 12, and desalinate or refine the same concentration by using a plurality of stages -ii-1 to the concentration device 12 'electrodialysis device, etc .; Dream; two Impure products with detection of si-based components in the concentrated solution, etc. # # ^ = better. And the concentration of these impurities is measured at appropriate times or often, for example, called roll-type desalination or refined. Si〇2 If the degree of roll exceeds i0mg / i, it will be described in the following two steps: it is difficult to obtain the local concentration, and it can be suitable for the concentrated solution. * * Only the reaction step. For example, for the concentration of S i 〇2 When it is more than one soil, you can control the opening and closing of the valve, and supply the concentrated liquid to the containing page 2042-5521-PF (Nl) .pld 200304428

CaI? 2 formation reaction step on the calcium fluoride recovery side of the impurities. On the other hand, if the concentration of SiO2 is lower than a certain standard, the valve can be opened and closed to control the supply of concentrated liquid to the high-purity calcium fluoride recovery side. CaFg formation reaction step. It is even better to provide a conductivity measurement device for the concentrated solution. By measuring the conductivity ', it is an effective device for the concentrated liquid to obtain information on its condition. 'Further', in the concentration-free treatment liquid (become the permeate side in the electrodialysis device) generated in the concentration step, the fluorine concentration is reduced to less than 20 mg / 1 'interventionally sent to the scrubber blast side Or the supply device 16 on the side of the exhaust gas elimination device can be supplied to the scrubber or the exhaust gas elimination device. In this way, reuse of the product in the concentration step can reduce the amount of wash water, treated water, and the like used in the exhaust gas treatment system. (Reaction step) Next, a preferable CaI? 2 generation reaction step suitable for the treatment technique of the present invention will be described. The reaction step is a step of generating caF2 by maintaining the pH of the reaction system obtained by adding about compound to the fluorine-containing waste water at 10 or more and 12.5 or less. In this step, there are at least one reaction tank, and it is also possible to have two or more reaction tanks. In the case of having two or more reaction tanks, the reaction solution can be configured to specifically flow between the reaction tanks by overflow. In addition, one slot can be actually divided into two or more reaction sections to form two or more reaction slots. The reaction tank can also be a storage tank as required. The dense liquid is supplied to the reaction tank through an appropriate supply device. reaction

2042-5521-PF (Nl) .ptd Page 17 200304428 V. Description of the Invention (ί) The tank may be provided with a device for detecting the pH of the reaction system in the tank, and a calcium compound such as (0H) 2 may be supplied to the reaction tank. Of the supply device 8. Furthermore, a fluorine ion concentration measuring device may be provided on the rear stage side in the reaction tank. (Mom compound) The calcium compound (hereinafter, also referred to as a fixative) that can be used to generate CaFg in this treatment technique is not particularly limited, and a compound previously used in this reaction can be used. For example, Caco, ca0 (quick lime), Ca (N03) 2, Ca (01!) 2, and the like can be used. If the reuse of the solid content obtained at the end of 3 is considered, JCa (0H) 2 is more preferable. In the case of using Ca (0H) 2, although it can also be supplied to the reaction vessel in the form of powder, solution, or the like, it is preferable to supply it in the form of a suspension suspended in water. In the polymer, a state in which Ca (0H) 2 particles are dispersed in a thick c'f (OH h solution) is formed. By using a slurry, based on the solubility of the reaction system ^ (0H) 2, the particles gradually Dissolved, so Ca (〇H) 2 is slowly supplied to the reaction system. Therefore, in the reaction system, for the formation of CaF2, the existence of excessive Ca (0H) 2 is avoided. As a result, whether it is obtained from The concentration of the Ca-based compound as an impurity is reduced as a solid or liquid (processed water). Although the slurry concentration of C a (〇Η) 2 is not particularly limited, it can be adjusted to about 20 wt% to about 40 wt%. Based on pH As for the detection device, the conditions for supplying the compound to the calcium to supply the calcium-based reaction solution in the reaction tank are preferable. If the pH is below 10, the concentrated solution is supplied to the reaction tank to use the compound. The amount of calcium compound supply is controlled The pH is applied. When the pH is maintained above 10 ′, the supply of calcium compounds is insufficient, and

200304428 V. Description of the invention (11) The reaction fluorine increased significantly. The upper limit is preferably 1 2 · 5 or less. If it exceeds 1 2 · 5, the supply of calcium compounds will be excessive, and there will be a large amount of calcium compounds as impurities in the solid content. According to this pH control, supply of an excessive amount of calcium compounds can be easily avoided, and as a result, CaF2 with high purity can be easily obtained. In addition, the supply amount of the calcium compound can be stopped when the fluoride ion concentration of the reaction solution is below a predetermined concentration; or when the fluoride ion concentration of the initial concentrated solution is at a predetermined ratio, for example, about 20% or less Supply to control. Based on such a control of the fluoride ion concentration, it is possible to reliably avoid an excessive supply of calcium compounds, and as a result, it is easy to obtain high-purity household CaF2. The control system of the supply amount of the compound is preferably controlled by the fluoride ion concentration, and is more preferably controlled by the fluoride ion concentration control and " control. Furthermore, when these two items are used for control, it is better to control the fluorine concentration first. For example, when the fluorine concentration of the concentrated solution is 5000 mg / i or less, the lower limit of the ion concentration is preferably set to about 5000 mg / l, and more preferably about 300 mg / i. In addition, the fluorine concentration of the initial concentrated solution is preferably about 20% to about 40% *. In this reaction step, Ca (011) 2 slurry is used as a calcifying agent. By performing the above pH control, on the one hand, it can avoid the presence of Ca in the reaction system, and on the other hand, it can effectively make CaI? 2. Settle down. Therefore, by applying the first step described above, it is easy to obtain high-purity CaI? 2. ’Wrong cause (neutralization step)

200304428 V. Description of the invention (12) After this reaction step, although the solid component containing CaF2 can be obtained by implementing the solid-liquid separation step, it is better to implement the neutralization step and the coagulation step before the solid-liquid separation step. The λ neutralization step is carried out in order to reduce the pH of the reaction solution in consideration of the safety of the solid component obtained at the end, and is therefore preferred. The neutralization step is preferably adjusted to ρΗ from 7.5 to 10.0, and more preferably from ρΗ to 8-9. As the neutralizing spark, various inorganic or organic acids can be used, but considering the use of the solid component obtained at the end, sulfuric acid is preferably used. If implemented in accordance with this treatment technique, in the above-mentioned reaction step, a neutralizing dose of sulfuric acid or the like required for neutralization can be reduced by suppressing or avoiding supply of an excessive amount of calcium compound '. As a result, a solid content with less impurities such as sulfate can be obtained. · ,, then-From the viewpoint of improving the efficiency and recovery rate of the two-solid separation step, the polymerization step is preferably a coagulation step after the second or second step or without a neutralization step. The coagulation ::: error is performed by adding a prepolymerized β such as a conventional polymer coagulant to form an aggregate. Agglomerating agents can be used, and these agglomerating agents can also be used technically, which is widely known to those skilled in the art. The treatment of the present invention (solid-liquid separation step) After the above reaction step is performed, it is preferable that the solid-liquid separation step 2 is performed before or after m: and the step and / or the process of applying the above-mentioned calcium compound Through the formation of the reaction step, you can get the control of the body, while controlling the body. The solid-liquid separation step can use the solid line of the known 3A purity CaFz. For example, you can use a filter or thickener to two Liquid separation device to apply on page 20 2042-5521-PF (Nl) .ptd 200304428 V. Description of the invention (13) The liquid separated in the solid-liquid separation step is used as a water-repellent treatment step as needed. 3 On the one hand, the separated Solid content; Pai'an's other Ca ingredients such as Ca salts are also reduced accordingly. Yes; Tundu's physical technology is implemented 'can produce 90% by weight or more of dextrogen. This high-purity CaF2 can be used as hydrogen It is said that the acid manufacturing raw material is added with 2 solids. Therefore, if implemented according to this processing technology, it can provide not only a ° -containing treatment, but also a raw material for hydrofluoric acid manufacturing. 7 i Plus: reuse A cyclic utilization system is produced using hydrofluoric acid as a semiconductor process. With this modification, if implemented according to this processing technology, in the reaction step, the supply of calcium compounds is controlled based on the fluoride ion concentration and / or pH. This can suppress the supply of excess calcium to the excess, that is, fluoride ions, which is present in the reaction. Therefore, the content of the fixing agent and other 5 in the solid component obtained at the end is reduced. Especially in In the reaction step, when the supply amount of the fixing agent based on the fluoride ion concentration is controlled, more accurate dosing agent supply control can be achieved, so that the final solid content of CaF2 content can have high purity and stability. When this treatment technology is implemented, in the reaction step, since the supply of the fixing agent is avoided, the amount of the neutralizer added can be reduced. Therefore, the generation of impurities such as calcium salts generated by neutralization can be suppressed. 'It helps to reduce the impurities in the final solid content. Especially' When using Ca (0H) 2 powder or slurry as a fixing agent in the reaction step, It is poorly soluble, so it slowly dissolves in the reaction system.

2042-5521-PF (Nl) .ptd Page 21 200304428 V. Description of the Invention (14)-To react slowly with fluoride ions. Therefore, the pH gradually changes. On the other hand, Ca (OH) 2 itself is strongly alkaline, and the reaction system can be easily maintained at strongly alkaline. Because of the above, if a powder or a slurry of Ca (OH) 2 (preferably a slurry) is used as a fixing agent, it is easy to avoid excessive supply of calcium. As a result, it is easy to obtain a solid component containing CaI? 2 with a high purity and a reduced calcium component other than CaF2. In addition, since only sulfuric acid is used as a neutralizing agent, and no nitric acid, hydrochloric acid, carbonic acid, phosphoric acid, or the like is used, an ideal raw material can be supplied for the production of hydrofluoric acid. For example, a solid content in which the total amount of nitrate ions, gas ions, and carbonate ions is 1 000 ppm or less can be obtained. In addition, the solid component system obtained in the solid-liquid separation step can be supplied to other reaction steps for generating a reaction in addition to recycling. In such a case, it is possible to effectively reuse the fixing agent remaining in the solid component. As described above, if implemented according to the present invention, the waste water containing a very small amount of fluorine is concentrated in the first stage of the reaction step for generating ^ 2, while removing the y component while concentrating, and implementing the concentration operation that can effectively use the treated water. Month b is enough to lighten the device for the CaFz generation step, and at the same time, it can recover high-purity CaF2, and the amount of CaF2 recovered can be increased. Furthermore, supplying the water part (permeate water) generated in the funeral process to the air purifier can effectively use the water part and reduce the amount of water used in the drainage treatment step. Effects of the Invention: If implemented according to the present invention, the

2042-5521-PF (Nl) .ptd

Page 22 200304428 V. Description of the invention (15) Enriched, can effectively use the treated water, and at the same time achieve effective drainage treatment in the later stage. 2042-5521-PF (Nl) .ptd Page 23 200304428 Brief Description of Drawings Figure 1 is a schematic diagram showing the steps and apparatus related to the processing technology of the present invention. Explanation of symbols: 2-pH adjusting tank, 4-acidifying agent supply device, 6-pH detection device, 8-fluorine concentrated liquid supply device, 10-float removal device, 1 2 -concentration device, 1 4 -filtration device , 16-supply device to scrubber or exhaust gas elimination device side, 20-storage tank, 22-Si02 concentration detection device, 24-reaction / coagulation tank / neutralization tank, 2 6-pH detection device 28-II Ca (0H) 2 °

2042-5521-PF (Nl) .ptd Page 24

Claims (1)

200304428 6. Scope of patent application 1. A method for treating fluorine-containing wastewater, comprising: a step of concentrating the fluorine-containing wastewater; a step of returning the treated water generated in the concentration step to a source of wastewater generation; A step of measuring the concentration of at least one component contained in the concentrate. 2. The method according to item 1 of the scope of patent application, wherein the concentration step is performed by electrodialysis. 3. The method according to item 2 of the patent application range, wherein the concentration step is performed on fluorine-containing drainage having a pH from 2 to 6 or fluorine-containing drainage having a pH adjusted to this range. 4. The method as described in item 3 of the scope of patent application, wherein the ρ Η of the fluorine-containing drainage is monitored, and when the fluorinated drainage has ρ 验, the step of adding an acidifying agent to the drainage is provided, and the step is set to concentrate Implemented before the steps. 5. The method according to item 4 of the scope of patent application, wherein the acidifying agent is HF. 2042-5521-PF (Nl) .ptd page 25 200304428 6. Application scope of patent The step of adding about compound to the concentrated solution to generate CaF2 as the reaction product; and the step of separating the reaction product from the concentrated solution. 9 · A fluorine-containing wastewater treatment device, comprising: a device for monitoring the pj of fluorine-containing wastewater, a device for supplying an acidifying agent to the fluorine-containing wastewater, a device for continuous electrodialysis of the fluorine-containing wastewater, and an electrodialysis device A device for returning treated water to a drainage generation source. The device according to item 9 of the scope of patent application, further comprising a device for supplying a fluorine-containing concentrated liquid produced by electrodialysis as an acidifying agent to a fluorine-containing wastewater.