KR100569649B1 - System of Treating wastewater containing Hardly degradable fluorine - Google Patents

Abstract

The present invention relates to a system for treating fluorine-containing wastewater, and more particularly, fluorine-containing wastewater capable of treating not only wastewater including fluorine generated in a production process but also hardly decomposable fluorine-containing compounds. To a processing system.

The hardly decomposable fluorine-containing wastewater treatment system according to the present invention comprises a water collecting tank, a reaction tank and a sedimentation tank, the first step of removing fluorine in the form of calcium fluoride, and hydrolyzable fluorine compound to easily decompose fluorine into fluorine. After the separation, a second step of removing fluorine in the form of calcium fluoride, wherein the high temperature and high pressure reactor performing hydrolysis of the hardly decomposable fluorine compound transfers the wastewater to have the optimum temperature, pressure and pH for the reaction. A chemical injection pipe communicating with a wastewater transfer pipe, an air injection pipe for injecting high-pressure air, a steam injection pipe for injecting hot air, and a chemical injection pipe for injecting a chemical for improving pH decomposition and decomposition efficiency of hardly decomposable fluorine substances; It is configured to include a stirring device, meter and discharge pipe inside.

The present invention thus constructed maximizes the efficiency of fluorine removal from the fluorine-containing waste water because the hydrolyzable fluorine compound is hydrolyzed to facilitate treatment.

Also, it can be applied to high concentration fluorine-containing wastewater treatment (raw water HF concentration 5000 ~ 10000ppm), so it can be treated stably without changing raw water concentration, and in general, it is possible to treat fluorine concentration below 10ppm only by the first stage treatment of primary process. Do.

Hydrofluoric acid, hardly decomposable fluorine-containing wastewater, fluorine, high temperature and high pressure reactors, hydrolysis.

Description

System of Treating wastewater containing Hardly degradable fluorine}

1 is a schematic view showing a system for treating a conventional fluorine-containing wastewater.

2 is a schematic view showing a hardly decomposable fluorine-containing wastewater treatment system according to the present invention.

3 is a process flow diagram showing a second process of the hardly decomposable fluorine-containing wastewater treatment system according to the present invention.

4 is a schematic view showing a device including a high temperature and high pressure reactor for hydrolyzing a hardly decomposable fluorine compound in a second process of the present invention.

FIG. 5 is a cross-sectional view illustrating a chemical mixing part mixing the hardly decomposable fluorine-containing wastewater and the chemical in FIG. 4; FIG.

*** Explanation of symbols for the main parts of the drawing ***

1: Hardly degradable fluorine-containing wastewater treatment system

100: first step 200: second step

201: wastewater transport pipe 202: steam injection pipe

203: air injection pipe 204: chemical injection pipe

210: high temperature and high pressure reactor 220: heat exchanger

230: steam exchange unit 240: chemical mixing unit

The present invention relates to a system for treating fluorine-containing wastewater, and more particularly, to a hardly decomposable fluorine compound capable of treating not only wastewater including general fluorine generated in a production process but also hardly decomposable fluorine compound. It relates to a containing wastewater treatment system.

Fluorine is a useful substance that is used in large quantities in various industrial fields such as chemical industry and semiconductor manufacturing, whereas fluorine contained in various industrial effluents is strictly regulated because it is a harmful substance to humans and the environment.

For example, in Korea, emission standards for fluorine compounds in wastewater are set to 3 ppm or less in clean areas and 15 ppm or less in other waste water discharge areas. In addition, in Japan, emission limits are regulated at concentrations of 15 ppm or less, but many Japanese municipalities apply more stringent standards, such as 10 ppm or less or 5 ppm or less.

In general, the main sources of fluorine-containing wastewater are hydrofluoric acid, octane fuel (catalyst), aluminum, semiconductor, steel, metal processing, electroplating, glass, ceramic, stainless, and fertilizer. In the industrial production process, a large amount of wastewater containing fluorine is generated, and various fluorine treatment methods for treating the fluorine are developed.

The most widely used of these methods is the use of calcium salts. One or more chemicals, such as calcium salts and aluminum salts, are added to fluorine-containing wastewater, and the fluoride ions in the wastewater are converted into calcium fluoride as shown in Eq. (1). It is a method of solid-liquid separation by solidifying to form.

Ca ²⁺ + 2F ^- ⇔ CaF ₂ (s) ↓ ----------- Formula (1)

In addition, fluoride is removed by aluminum by injecting an alum such as Al ₂ (SO ₄ ) ₃ .18H ₂ O. At this time, the polymerized Al _n (OH) _3n has a strong affinity with fluorine ions. Adsorbed and removed.

As a system using this method, as shown in Fig. 1, a collecting tank 2 for collecting wastewater containing fluorine, and a plurality of reaction tanks for reacting with fluorine by adding the calcium salt, aluminum salt and a polymer flocculant (3). , 5) and sedimentation tanks 4 and 6 for solid-liquid separation of the solidified fluorinated fluoride.

However, this method is not economical because the processing efficiency of fluorine is low and a large amount of calcium and aluminum salts are required to be injected, resulting in excessive treatment cost, and the amount of sludge, which is a precipitate, increases due to the increase of the treating agent. Has a problem.

In addition, since the desired fluorine treatment efficiency can be obtained by treating the system as shown in FIG. 1 in at least two to three stages, the number of stages required for the installation of the wastewater treatment plant is increased, the system becomes complicated, and operation and management costs are increased. Occurs. In addition, a large amount of aluminum-based sludge is generated, there is a difficulty in recycling.

For example, calcium fluoride generated when treating 10 m 3 of fluorine concentration of 210 ppm to 20 ppm is about 0.39 kg (about 5 mol), whereas aluminum hydroxide is required to treat 10 m 3 of fluorine concentration of 20 ppm of waste water to 5 ppm. At least about 2 kg (25.6 mol) is required as Al (OH) ₃ . In reality, aluminum hydroxide is difficult to dehydrate in a gel state, and even if the water content is reduced to 70%, the water weight is about 5 kg, which is treated with sludge.

In addition, I-decomposable fluorine compound there is the present in the same waste water without being treated, LCD manufacturing process, B ₂ O ₃ generated look as an example GLASS composition is melted by a HF in the etching process and the boron hydrofluoric acid (HBF ₄₎ This BF ₄ is a very stable compound and is a hardly decomposable fluorine compound which cannot be removed by a general treatment method.

If B of BF _{4 in} the wastewater is present in 30 ppm, the conventional method is difficult to process, and only the dilution concept can be treated with a large amount of dilution water. When the concentration of B is 30 ppm, the F concentration of the treated water is about 210 ppm.

Therefore, there is a need for a method of treating wastewater containing such a hardly decomposable fluorine compound.

The present invention is to solve the above problems, it is possible to remove the fluorine in the fluorine-containing waste water in a low concentration, compared to the conventional treatment method, and difficult to be treated including hardly decomposable fluorine material that does not decompose well It is an object to provide a decomposable fluorine-containing wastewater treatment system.

In addition, an object of the present invention is to provide a hardly decomposable fluorine-containing wastewater treatment system capable of minimizing the amount of sludge while reducing the amount of chemicals to be injected.

In order to achieve the above object, the hardly decomposable fluorine-containing wastewater treatment system according to the present invention is a hardly decomposable fluorine using a first process and a high temperature and high pressure reactor in which Ca (OH) ₂ and a fluorine treatment agent are injected to aggregate the fluorine in the wastewater. It consists of a 2nd process of removing a compound.

The first process includes a water collecting tank for collecting fluorine-containing wastewater including hardly decomposable fluorine, a first reaction tank in which the waste water passing through the collecting tank solidifies with calcium fluoride by reacting with the fluorine treatment agent, and a waste water and fluorination solution through the first reaction tank. It comprises a first sedimentation tank for coagulation sedimentation and separation of calcium.

The second step is a high temperature and high pressure reactor for hydrolyzing the hardly decomposable fluorine compound in the wastewater that has passed through the first step, and the fluorine treatment agent is added together with the wastewater that has passed through the high temperature and high pressure reactor to be hydrolyzed in the high temperature and high pressure reactor. And a second reaction tank for solidifying fluorine with calcium fluoride, and a second settling tank for coagulating and sedimenting the wastewater and calcium fluoride which have passed through the second reaction tank and returning some of the solid-liquid separated sludge to the reactor.

At this time, the fluorine treatment agent added to the wastewater and reacted with fluorine ions is calcium salts such as Ca (OH) ₂ , iron salts containing Fe ions, pH-controlled acidic chemicals, and polymers (strong anionic polymer flocculants). It reacts with the calcium salt to solidify it in the form of calcium fluoride, and the ferric hydroxide produced by the iron salt and the calcium fluoride have a coprecipitation effect to increase the fluorine treatment removal efficiency in the wastewater.

The hardly decomposable fluorine compound is hydrofluoric acid (HBF ₄ ), and the BF ₄ is hydrolyzed in a high temperature and high pressure reactor of a second process to be separated into boron and fluorine, and the separated fluorine is formed of calcium fluoride by calcium salt. It solidifies in form and is subjected to flocculation sedimentation.

On the other hand, the high temperature and high pressure reactor for hydrolyzing the hardly decomposable fluorine compound to easily decompose the wastewater transfer pipe for transporting the hardly decomposable fluorine-containing wastewater passed through the first step to one side, an air injection pipe for injecting high-pressure air, The steam injection pipe for injecting hot steam is included and connected, and if necessary, includes a chemical injector for mixing the fluorine treatment agent.

The high temperature and high pressure reactor includes a stirring device for mixing the hardly decomposable fluorine-containing wastewater introduced therein, a meter for measuring whether the temperature, pH, and pressure in the reactor maintain an optimum state for easy hydrolysis; Forming a space on one side of the high-temperature high-pressure reactor for transporting the hydrolyzed wastewater, and comprises a wall of the height having the same surface as the inner surface of the reactor, and a discharge pipe for discharging the treated water overflowing the overflow wall do.

The high temperature and high pressure reactor may include a heat exchanger in which heat exchange occurs between a wastewater transfer pipe for transporting wastewater that has passed through a first process and a discharge tube of the high temperature high pressure reactor, and a wastewater transfer pipe passing through the heat exchanger and the steam injection tube communicate with the wastewater. The venturi tube-shaped steam mixing part in which hot steam is mixed, the waste water transfer pipe passing through the steam mixing part, and the chemical injection tube for injecting chemicals to increase the pH and control the decomposition efficiency of the hardly decomposable fluorine substance are connected to each other. The drug mixture to be mixed is configured to be included outside.

At this time, preferably the pH of the high temperature and high pressure reactor is between 3 and 4, the pressure of the high temperature and high pressure reactor is 1.5kg / cm 2 ~ 3kg / cm 2, the temperature of the high temperature and high pressure reactor is 110 ~ 130 ℃.

In addition, the chemical mixing portion of the high-temperature high-pressure reactor is a tube with a spiral groove formed on the inner circumferential surface is mixed with the chemical injected through the chemical injection pipe while controlling the waste water moves along the spiral line to adjust the pH of the waste water.

And, all the above process steps are automatically controlled or manually controlled by an externally formed control box.

The hardly decomposable fluorine-containing wastewater treatment system thus formed can be treated by calcium fluoride with fluorine using only a small amount of the treatment agent by use of the iron salt. In addition, since the hardly decomposable fluorine compound is hydrolyzed in the high temperature and high pressure reactor to be separated into fluorine which is easy to treat, the fluorine treatment efficiency is maximized.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view showing a hardly decomposable fluorine-containing wastewater treatment system according to the present invention, FIG. 3 is a process flow chart showing a second process of the hardly decomposable fluorine-containing wastewater treatment system according to the present invention, and FIG. Schematic diagram showing a device including a high temperature and high pressure reactor to hydrolyze a hardly decomposable fluorine compound in two processes.

In addition, Figure 5 is a cross-sectional view showing a chemical mixing portion for mixing the difficult-degradable fluorine-containing wastewater and the chemical in FIG.

As shown, the hardly decomposable fluorine-containing treatment system 1 according to the present invention includes a first step 100 for treating a fluorine compound that is easily treated in wastewater, and a second step for treating a hardly decomposable fluorine compound in wastewater. Process 200 is made.

The first step 100 is a process for solidifying and treating fluorine in waste water in the form of calcium fluoride, and a water collection tank 10 into which wastewater containing hardly decomposable fluorine flows, calcium salts such as Ca (OH) ₂ , and Fe The primary reaction tank 20 into which the fluorine treatment agent which consists of iron salt containing ion, pH-controlled acidic chemicals, and a polymer (a strong ionic polymer flocculant), and the fluorine in the wastewater which passed the said reaction tank were solidified with calcium fluoride, and solidified. Separation and some solid-liquid separated sludge is conveyed and consists of a primary sedimentation tank (30) for transporting the waste water to the next fixed. At this time, the primary reaction tank 20 uses a plurality of reaction tanks depending on the chemical in order to efficiently react the fluorine compound depending on the chemicals to be injected.

Then, a predetermined fluorine-containing wastewater is transferred to the reaction tank 20 through the sump tank 10, and calcium salt is added to make the pH of the wastewater at 7 or more to solidify the fluorine ions in the wastewater in the form of calcium fluoride to solid-liquid separation. Preferably, a portion of the produced sludge is returned to the reactor 20 to concentrate the concentration of calcium fluoride generated in the reactor and at the same time, the efficiency of removing fluorine from the fluorine-containing wastewater by the seed crystallization effect of the produced calcium fluoride. To improve. At this time, the calcium salt is used Ca (OH) ₂ .

In addition, when the fluorine-containing wastewater to be treated is continuously or intermittently injected into the appropriate reactor 20, iron salt is added to increase the efficiency of the reaction. Preferably, the iron salt contains Fe ions to increase the fluorine removal efficiency by the coprecipitation effect of ferric hydroxide and calcium fluoride formed by adding ferric ions.

At this time, in the case of using the ferric ions there is no particular limitation on the amount of ferric ions produced calcium fluoride (CaF ₂ ) It is about 0.12 to 1.2 times the molar concentration, and 0.23 to 0.47 times is particularly preferable. If the use concentration is small, the improvement of the fluorine treatment efficiency due to the coprecipitation effect cannot be expected. On the contrary, if the injection amount is excessive, the amount of chemicals to be treated increases, which is undesirable.

The fluorine-containing wastewater containing no hardly decomposable fluorine can be stably treated only by the first step of the first stage, and can be stably treated even when the raw water concentration of the wastewater changes. In addition, a small amount of chemical can be added to the desired water quality as a synergistic effect by the seed crystallization and coprecipitation effect.

In addition, since no aluminum-based chemicals are used, there is no problem in reuse of the treated sludge, and the fluorine may be treated by calcium fluoride using only a small amount of the treating agent using the iron salt.

However, hardly decomposable fluorine compounds such as fluorine boride (BF ₄ ) are not removed in the first step. In the secondary process 200 for treating such hardly decomposable fluorine compounds, the hardly decomposable fluorine-containing wastewater passing through the primary settling tank 30 is transferred to the pumping tank 40 together with the dehydration remaining after dewatering the sludge. And the pumping tank 40 is transferred to the high temperature and high pressure reactor 210 together with the hot steam, chemicals to increase the pH and control the decomposition efficiency of the hardly decomposable fluorine material. In addition, the fluorine-containing waste water hydrolyzed in the high temperature and high pressure reactor 210 is transferred to the secondary reaction tank 50 and reacted with a treatment agent such as calcium salt, iron salt, pH controlled acidic chemicals, polymer, and the like. It is solidified in the form and is removed through the coagulation sedimentation process in the secondary settling tank (60). At this time, referring to Figure 3, preferably, the wastewater passing through the second reaction tank 50 and the second settling tank 60 is conveyed by the conveying pipe 80 to increase the fluorine treatment efficiency.

In addition, the first process 100 and the second process 200 are automatically controlled or manually controlled by the control box 111 formed outside.

In general, B ₂ O ₃ generated during the LCD manufacturing process is melted by HF in the etching process to form hydrofluoric acid (HBF ₄ ). This BF ₄ is a very stable compound and is a hardly decomposable substance that cannot be removed by a general treatment method.

To treat this BF ₄ , the basic is hydrolysis to separate boron and fluorine, and then fluorine is treated in the form of calcium fluoride.

HBF ₄ + H ₂ O → HBF ₃ (OH) + HF ------- ①

HBF ₃ (OH) + H ₂ O → HBF ₂ (OH) ₂ + HF ------- ②

HBF ₂ (OH) ₂ + H ₂ O → HBF ₃ (OH) ₃ + HF ------- ③

HBF (OH) ₃ + H ₂ O → H ₃ BO ₃ + HF ------- ④

The high temperature and high pressure reactor 210 induces the hydrolysis reaction with the optimum temperature, pressure, pH conditions to treat the BF ₄ which is a hardly decomposable material.

As such, the wastewater containing the hardly decomposable substance separated from boron and fluorine is transferred to the second reactor 50 and the fluorine is treated and removed in the form of calcium fluoride by the injected calcium salt.

Referring to FIG. 4, the high temperature and high pressure reactor 210 of the second process 200 to hydrolyze the hardly decomposable fluorine compound is as follows.

The high temperature and high pressure reactor 210 is configured to maintain temperature, pressure, and pH in optimal conditions in order to hydrolyze a hardly decomposable fluorine compound, for example, hydrofluoric acid to separate boron and fluorine.

At this time, the temperature of the high temperature and high pressure reactor 210 is suitable for 110 ~ 130 ℃, pH 3 ~ 4 and pressure to maintain 1.5kg / ㎠ ~ 3kg / ㎠.

To this end, the high temperature and high pressure reactor 210 is a wastewater transport pipe 201 for transporting the hardly decomposable fluorine-containing wastewater, an air injection pipe 203 for injecting high pressure air, and a steam injection pipe for injecting hot steam. The chemical injection tube 204 which communicates with 202, and which is injected in order to adjust pH and increase the decomposition efficiency of the hardly decomposable fluorine substance, is configured to communicate directly or indirectly as necessary. In addition, a meter for measuring the temperature, pH, pressure inside the stirring apparatus 211 and the high temperature and high pressure reactor 210 to mix the hardly decomposable fluorine-containing waste water to facilitate hydrolysis in the high temperature and high pressure reactor 210. 212 and the overflow wall 213 of the height which has the same water surface as the inner surface, and the discharge pipe 214 for discharging the treated water.

The heat exchanger 220, the steam mixing unit 230, and the chemical mixing unit 240 are included outside the high temperature and high pressure reactor to hydrolyze the hardly decomposable fluorine compound in the wastewater.

First, the wastewater transport pipe 201 is a pipe for transporting the wastewater passing through the pumping tank 40 for collecting the wastewater containing the hardly decomposable fluorine compound passed through the primary process 100 and the dehydration filtrate dehydrated the sludge. While passing through the steam mixing unit 230 and the chemical mixing unit 240 has a temperature and pH that is easy to hydrolyze the hardly decomposable fluorine compound, it is preferably in communication with the upper portion of the high temperature and high pressure reactor (210).

In addition, the air injection pipe 203 is for controlling the pressure by forcibly injecting high-pressure air into the high temperature and high pressure reactor 210 to the pressure in the reactor into 1.5kg / ㎠ ~ 3kg / ㎠ for easy hydrolysis Keep it.

In addition, the steam injection pipe 202 is for controlling the temperature is divided into two by a plurality of valves 205, one is connected to the lower portion of the high temperature and high pressure reactor 210 to direct hot steam into the reactor The other is connected to the steam mixing unit 230 is mixed with the waste water conveyed by the waste water conveying pipe 201 to increase the temperature of the waste water.

At this time, the steam injection pipe 202 directly connected to the high temperature and high pressure reactor 210 is operated at the initial or emergency to operate the reactor to maintain the temperature of the reactor 110 to 130 ℃ easy for hydrolysis.

As such, the high temperature and high pressure reactor 210 having an optimal temperature, pressure, and pH for easy hydrolysis of the hardly decomposable fluorine compound is mixed with the wastewater using the internal agitator 211, and the hardly decomposable fluorine in the mixing process. Compound HBF ₄ is hydrolyzed to boron and fluorine. In addition, the hydrolyzed wastewater containing fluorine is discharged through the discharge pipe 214 formed at the lower side by overflowing the overflow wall 213 having a ware formed thereon.

In this case, preferably, the overflow wall 213 is formed to form a space by partitioning one side of the high temperature and high pressure reactor 210 and have the same height as the water surface in the reactor, and the discharge pipe 214 is the overflow wall 213. The supernatant is transported in the wastewater containing hydrolyzed fluorine which is located in the space to form.

In addition, the outside of the high temperature and high pressure reactor 210 is configured to include a heat exchanger 220 as a heat recovery system in order to save energy, the exhaust pipe 214 and the pumping tank (Fig. 2) in the heat exchanger 220 , The heat exchange of the waste water transfer pipe 201 for transferring the waste water from the 40 takes place. The temperature inside the high temperature and high pressure reactor 210 maintains the temperature of the treated water transferred along the discharge pipe 214 at a temperature of 110 to 130 ° C. that is easy for hydrolysis, and the waste water transfer pipe 201. The fluorine-containing wastewater transported along is maintained at room temperature. Therefore, in the heat exchanger, the discharge pipe 214 and the waste water conveying pipe 201 are heat-exchanged so that the fluorine-containing waste water rises a certain temperature and the treated water is preferably transferred to the next process while maintaining a temperature of 40 ° C or less.

In addition, the wastewater transport pipe 210 that has passed through the heat exchanger 220 is in communication with the steam injection pipe 202 and the steam mixing unit 230 before the wastewater flows into the high temperature and high pressure reactor 210 to perform the temperature. Will be maintained. At this time, the steam mixing unit 230 is a place where the gas and liquid is mixed preferably has the shape of a venturi tube and the steam inlet pipe 202 for transferring hot water and the waste water transfer pipe 201 is connected to one side have.

At this time, the steam injection pipe 202 is divided by the valve 205 into a separate pipe and a pipe communicating with the high temperature and high pressure reactor 210 and preferably most hot steam through the steam injection pipe 202 It is introduced into the steam mixing unit 230 to increase the temperature of the waste water.

In addition, the waste water transfer pipe 201 is in communication with the chemical injection pipe 204 and the chemical mixing unit 240 in order to maintain the optimum pH before the waste water is introduced into the high temperature and high pressure reactor 210 to adjust the wastewater and pH. Mix the medicine.

The chemical injection pipe 204 is a tube in which a chemical is injected to maintain the pH in the high temperature and high pressure reactor 210 at 3 to 4 and increase the decomposition rate of the hardly decomposable fluorine material, and the chemical is steam in the chemical mixing unit 240. The temperature is increased and the hydrolysis efficiency of the waste water is passed through the mixing unit 230 is communicated with the waste water transfer pipe 201 is transferred through the waste water transfer pipe.

In addition, the chemical mixing unit 240 is a pipe containing an inner circumferential surface of the spiral groove as shown in FIG. 5 and the wastewater in the chemical mixing unit 240 is moved while rotating along the spiral groove. At this time, the medicine injected through the drug injection pipe 204 formed in communication with one side of the drug mixing unit 240 is mixed evenly mixed in the waste water rotating along the spiral groove and thus the waste water of the hardly decomposable fluorine compound It will have an optimal pH that is easy to hydrolyze.

Referring to FIG. 4 again, the hardly decomposable fluorine-containing wastewater having a temperature rise and having an appropriate pH is introduced into the high temperature and high pressure reactor 210 through the wastewater transport pipe 201.

The hydrolysis process of the hardly decomposable fluorine compound in the high temperature and high pressure reactor 210 configured as described above will be described according to the flow of waste water.

First, the wastewater containing the hardly decomposable fluorine compound pumped into the pumping tank (FIGS. 2 and 40) is transferred by the wastewater conveying pipe 201, and the wastewater is heat-exchanged while the wastewater conveying pipe 201 passes through the heat exchanger 220. The temperature rises to some extent.

In addition, the wastewater has an optimum temperature that is easy to hydrolyze by hot steam injected from the steam mixing unit 230, the pH control chemicals injected from the chemical mixing unit 240 and the removal efficiency of the hardly decomposable fluorine material The pH is maintained by the chemical to increase the 3 to 4, the waste water temperature and pH is adjusted in this way is introduced into the high temperature and high pressure reactor 210 by the waste water transfer pipe (201).

Next, the wastewater is subjected to a pressure of 1.5㎏ / ㎠ ~ 3㎏ / ㎠ by the high-pressure air injected through the air injection pipe 203 in the high temperature and high pressure reactor 210 and hardly decomposable fluorine compound contained in the wastewater HBF ₄ is hydrolyzed to separate boron and fluorine.

In addition, the hydrolyzed fluorine-containing wastewater is transferred to the second reactor 50 and the second settling tank 60 along the discharge pipe 214 formed on one side of the high temperature and high pressure reactor 210 beyond the overflow wall 213. The fluorine is solidified and treated in the form of calcium fluoride by a fluorine treatment agent such as injected calcium salt and iron salt.

The present invention described above is limited to the above-described embodiment and the accompanying drawings as various substitutions and modifications can be made within a range without departing from the technical spirit of the present invention for those skilled in the art. It doesn't happen.

The fluorine-containing wastewater treatment system of the present invention made as described above maximizes the fluorine removal efficiency from the fluorine-containing wastewater because hydrolyzable hardly decomposable fluorine compounds are easily hydrolyzed.

Also, it can be applied to high concentration fluorine-containing wastewater treatment (raw water HF concentration 5000 ~ 10000ppm), so that it can be treated stably without changing raw water concentration, and in general, it is possible to treat fluorine concentration 10ppm or less with only one step treatment. .

Claims (5)

A water collecting tank for collecting the hardly decomposable fluorine-containing waste water, a first reaction tank in which the waste water passing through the water collecting tank solidifies with calcium fluoride by reacting with a fluorine treatment agent, and a first separation for coagulation and sedimentation of the waste water and calcium fluoride which have passed through the first reaction tank. A first step comprising a sedimentation tank; Solidifying the hydrolyzed fluorine with calcium fluoride in a high temperature and high pressure reactor by adding a fluorine treatment agent together with the high temperature and high pressure reactor for hydrolyzing the hardly decomposable fluorine compound in the wastewater that has passed the first process, and the wastewater that has passed through the high temperature and high pressure reactor. A second step including a second reactor and a second settling tank for coagulating and sedimenting the wastewater and calcium fluoride which have passed through the second reactor for solid-liquid separation; The fluorine treatment agent is a calcium salt, an iron salt containing Fe ions, a pH-controlled acidic chemical, a polymer (a strong anionic polymer flocculant), and the fluorine in the waste water reacts with the calcium salt to form calcium fluoride, which is produced by the iron salt. A non-degradable fluorine-containing wastewater treatment system, characterized in that the ferric hydroxide and the calcium fluoride cause a coprecipitation effect. The method of claim 1, The hardly decomposable fluorine compound is hydrofluoric acid (HBF ₄ ) and the BF ₄ is hydrolyzed in a high temperature and high pressure reactor of the second process to be separated into boron and fluorine, and the separated fluorine is in the form of calcium fluoride by calcium salt. A non-degradable fluorine-containing wastewater treatment system, characterized in that it is fixed. The method according to claim 1 or 2, The high temperature and high pressure reactor is in communication with the wastewater conveying pipe for conveying the hardly decomposable fluorine-containing wastewater, the air injection pipe for injecting high pressure air, and the steam injection pipe for injecting hot steam; A stirring device for mixing the fluorine-containing wastewater inside the high temperature and high pressure reactor; A meter for measuring temperature, pH, and pressure in the high temperature and high pressure reactor; A wall overflow wall having a height formed on one side of the high temperature and high pressure reactor and having the same surface as the inner surface of the reactor; A discharge pipe for discharging the treated water that has flowed through the overflow wall; A heat exchanger in which heat exchange occurs between a wastewater transfer pipe for transferring the wastewater passed through the first process and a discharge pipe of the high temperature and high pressure reactor; A vent mixing tube-shaped steam mixing part in which the waste water transfer pipe passing through the heat exchanger and the steam injection pipe communicate with each other to mix waste water and hot steam; The waste water transfer pipe passing through the steam mixing unit and the chemical injection tube for injecting a chemical to increase the decomposition efficiency of the pH control and the hardly decomposable fluorine material are communicated to include a chemical mixing part in which the waste water and the chemical is mixed outside of the high temperature and high pressure reactor. A non-degradable fluorine-containing wastewater treatment system comprising: The method of claim 3, wherein The pH of the high temperature and high pressure reactor is between 3 and 4, the pressure of the high temperature and high pressure reactor is 1.5kg / ㎠ ~ 3kg / ㎠, the temperature in the high temperature and high pressure reactor is 110 ~ 130 ℃ characterized in that the hardly decomposable fluorine Containing wastewater treatment system. The method of claim 3, wherein The chemical mixing part of the high temperature and high pressure reactor is a tube in which the inner circumferential surface is formed with a spiral groove, and the waste water moves along the spiral groove to be mixed with the chemical injected through the chemical injection tube to adjust the pH of the waste water. Refractory fluorine-containing wastewater treatment system.

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