JP2005305279A - Method and apparatus for treating fluorine-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating fluorine-containing water which can continue the treatment of fluorine-containing water without interruption during the regeneration of a granular material mainly comprising calcium carbonate. <P>SOLUTION: The fluorine-containing water treatment apparatus comprises a transfer pipe 8 having a first opening 8a opened at a part located at the lower part of a packed bed 4 and a second opening 8b opened at a part located higher than the upper surface of the packed bed 4, a fluid supply means 10 for supplying fluid into the transfer pipe 8 so that upward flow of a fluid is generated in the transfer pipe 8 to transfer the granular material and treated water sucked from a first opening 8a into the transfer pipe 8, films of calcium fluoride of the granular material are broken and removed by mutual collision in the granular material and collision with the inner wall of the transfer pipe 8, and the granular material and the treated water are discharged from a second opening 8b, and a separation mean for separating the granular material and the treat water to return the granular material discharged from the second opening 8b to the packed bed 4, and to discharge the treated water discharged from the second opening 8b to the outside of a reaction tank 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention allows fluorine-containing water to flow into a reaction treatment tank in which a packed bed composed of a granular material containing calcium carbonate as a main component is formed, and the reaction between the fluorine component in the fluorine-containing water and the granular calcium carbonate. The present invention relates to a treatment apparatus for fluorine-containing water that forms a film made of water-insoluble calcium fluoride on the surface of a granular material and removes a fluorine component from fluorine-containing water, and a treatment method for fluorine-containing water using the same.

A large amount of fluorine-containing wastewater containing water-soluble fluorine compounds (fluorine components) such as HF or H ₂ SiF ₆ is discharged from semiconductor, liquid crystal, and crystal processing factories.
As a method for removing the fluorine component from the fluorine-containing wastewater, a method using slaked lime or a method using calcium carbonate is known.

In the method using slaked lime, by adding slaked lime to the fluorine-containing wastewater, the fluorine component and slaked lime are reacted, the fluorine component is precipitated as water-insoluble calcium fluoride, and the fluorine component is removed. Yes.
However, in this method using slaked lime, it is necessary to add slaked lime of a reaction equivalent or more so as to be able to cope with fluctuations in the fluorine concentration of the fluorine-containing wastewater. Therefore, not only calcium fluoride, which is a reaction product with fluorine, but also unreacted slaked lime is discharged, resulting in a large amount of sludge.

On the other hand, in the method using calcium carbonate, a fluorine-containing wastewater is passed through a packed tower (reaction treatment tank) in which a packed bed made of a granular material containing calcium carbonate as a main component is formed. And react. The water-insoluble calcium fluoride produced as a result of this reaction remains as a film on the surface of the granular material, and the fluorine component is removed from the fluorine-containing water.
This method using calcium carbonate does not generate unreacted sludge even if the fluorine concentration varies, reduces the residual fluorine component concentration of treated water after treatment, and the cost of treatment chemicals is low. This is advantageous compared to the method using slaked lime.

  However, in this method using calcium carbonate, if the fluorine component removal treatment is continued, the surface of the granular material is covered with a calcium fluoride film, and the fluorine removal ability is lowered.

In this regard, the present inventor previously proposed a treatment apparatus for fluorine-containing water in Patent Document 1 that can regenerate a granular material mainly composed of calcium carbonate having reduced fluorine removal ability.
A schematic diagram of such a fluorine-containing water treatment apparatus is shown in FIG. In the fluorine-containing water treatment apparatus B shown in FIG. 3, the raw water pump 40 is driven into the packed tower 70 filled with a filler 75 composed mainly of calcium carbonate. By doing so, a calcium fluoride film is formed on the surface of the granular material, and the fluorine component in the fluorine-containing water is removed. Then, the backwash water pump 41 is driven so that the calcium fluoride film can be pulverized and removed during the regeneration treatment of the granular material in which the calcium fluoride film is formed and the fluorine removing ability is reduced. A stirrer 81a capable of forcibly stirring the granular material in the backwash water is provided in the packed tower 70.

  According to the treatment apparatus B for fluorine-containing water shown in FIG. 3, the calcium fluoride film formed on the surface of the granular material can be removed, and the fluorine removing ability of the granular material can be regenerated.

JP 2003-181468 (paragraphs 0008-0009, FIG. 1)

However, in the treatment apparatus B for fluorine-containing water shown in FIG. 3, the treatment of fluorine-containing water must be interrupted when regenerating the particulate matter having reduced fluorine removal capacity, and the treatment efficiency of fluorine-containing water is reduced. Decreases.
In particular, when treating fluorine-containing water containing a high concentration of fluorine component, a calcium fluoride film is easily formed on the surface of the granular material in a short time. For this reason, it is necessary to increase the frequency of the regeneration processing of the particulate matter, and the processing efficiency further decreases.

For this reason, the processing apparatus with higher processing efficiency of fluorine-containing water than the processing apparatus B shown in FIG. 3 is desired.
Accordingly, the problem to be solved by the present invention is that a fluorine-containing water treatment apparatus and treatment that can continue the treatment of fluorine-containing water without interruption even during the regeneration treatment of the granular material mainly composed of calcium carbonate. It is to provide a method.

The present inventor considered that it is effective to simultaneously perform the removal of the calcium fluoride film formed on the surface of the granular material and the treatment of the fluorine-containing water in order to solve the above problems. Reached.
The fluorine-containing water treatment apparatus according to the present invention has the following configuration in order to solve the above problems. That is, fluorine-containing water is passed through a reaction treatment tank in which a packed bed composed mainly of calcium carbonate is formed, and water-insoluble due to the reaction between the fluorine component in the fluorine-containing water and calcium carbonate in the granular material. In a fluorine-containing water treatment apparatus that forms a film made of porous calcium fluoride on the surface of a granular material and removes a fluorine component from fluorine-containing water, the tubular body extends upward from the lower part in the reaction treatment tank. A transfer pipe formed with a first opening opened on a side surface of a portion located below the packed bed and a second opening opened on a portion located above the upper surface of the packed bed; Then, an upward fluid flow is generated in the transfer pipe, and the treated water from which particulate matter and fluorine components in the lower part of the packed bed sucked into the transfer pipe from the first opening are removed is transferred to the transfer pipe. Top of The calcium fluoride film formed on the surface of the granular material is crushed and removed by collision with the granular materials and the inner wall of the transfer pipe, and is removed from the surface of the granular material and the granular material. Calcium fluoride pieces and fluid supply means for supplying fluid into the transfer pipe so as to discharge the treated water from the second opening, and particulate matter discharged from the second opening in the packed bed And separating means for separating the granular material and the treated water so as to discharge the treated water discharged from the second opening to the outside of the reaction treatment tank.

Furthermore, the upper end of the transfer pipe is closed, and when the granular material transferred through the transfer pipe collides, the calcium fluoride film formed on the surface of the granular material is crushed and removed. A collision wall is provided, and the second opening is formed on a side surface of the transfer pipe.
According to this, it is possible to remove the calcium fluoride coating more effectively by causing the particulate matter to collide with the collision wall.

Further, the fluid supply means generates a negative pressure inside the lower portion of the transfer pipe by supplying the fluid upward from the position above the first opening into the transfer pipe. The granular material and the treated water are sucked into the transfer pipe from the first opening.
According to this, the flow of the fluid for transferring the granular material and the treated water can be generated with a simple configuration.

Further, the separating means is a cylindrical body in which the second opening of the transfer pipe is located, and is disposed so that a bottom surface is in contact with an upper surface of the packed bed. A separation layer formed with a passing port for returning the accumulated granular material separated from the calcium fluoride pieces and the treated water by the separation means to the packed bed, and discharged from the second opening and the It has the drainage channel which discharges | emits the said calcium fluoride piece isolate | separated from the granular material and the said treated water from the said separation tank, It is characterized by the above-mentioned.
According to this, a granular material, a calcium fluoride piece, and treated water can be isolate | separated by simple structure.

Moreover, when the granular material collected in the said separation tank becomes less than predetermined amount, it is provided with the granular material supply means which supplies a granular material in a separation layer, It is characterized by the above-mentioned.
According to this, a predetermined amount or more of granular materials can be maintained in the separation tank, and a gap can be prevented from being generated between the upper surface of the packed bed and the bottom surface of the cylindrical body constituting the separation tank. For this reason, it can prevent that the fluorine-containing water supplied in the reaction processing tank bypasses in a separation tank, without passing a packed bed.

  Moreover, in order to solve the said subject, the processing method of fluorine-containing water which concerns on this invention is equipped with the following structures. That is, the fluorine-containing water treatment apparatus according to any one of claims 1 to 5 is used to remove the fluorine component in the fluorine-containing water.

In the fluorine-containing water treatment apparatus and treatment method according to the present invention, the particulate matter in the lower part of the packed bed sucked from the first opening formed in the lower part of the transfer pipe is transferred by the fluid supplied by the fluid supply means. It is transported from the bottom of the tube upward. At that time, the calcium fluoride coating covering the surface of the granular material is pulverized and removed by the collision between the granular materials and the inner wall of the transfer pipe, thereby regenerating the fluorine removing ability of the granular material.
Even during the regeneration of the fluorine treatment capacity of the granular material, the granular material having the fluorine treatment capacity filled outside the transfer pipe moves from the upper side to the lower side of the packed bed, while the fluorine component in the fluorine-containing water. Fluorine component can be removed by forming a calcium fluoride film.
As described above, the removal of the calcium fluoride film formed on the surface of the granular material and the treatment of the fluorine-containing water can be performed simultaneously. As a result, even if the fluorine-containing water contains a high concentration of fluorine components, The processing can be performed continuously without interruption, and the processing efficiency can be remarkably improved.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out a treatment apparatus and treatment method for fluorine-containing water according to the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory side view showing a configuration of a treatment apparatus A for fluorine-containing water according to the present embodiment, and FIG. 2 is an explanatory plan view of the treatment apparatus A for fluorine-containing water.

  As shown in FIG. 1, in the treatment apparatus A for fluorine-containing water, a packed bed 4 is formed in a reaction treatment tank 2, which is filled with granular materials mainly composed of calcium carbonate. This granular material is sieved using limestone as a raw material, and crystalline heavy calcium carbonate is particularly preferably used.

Further, above the reaction treatment tank 2, fluorine-containing wastewater containing a water-soluble fluorine compound (fluorine component) such as HF or H ₂ SiF ₆ discharged during processing of semiconductor, liquid crystal, crystal, or the like. A raw water supply pipe 6 for supplying the reaction treatment tank 2 (hereinafter sometimes simply referred to as fluorine-containing water) is provided.
The raw water supply pipe 6 communicates with a transport pump (not shown) that supplies fluorine-containing waste water to the upper part of the reaction treatment tank 2.

In the reaction processing tank 2, a transfer pipe 8 made of a cylindrical body extending upward from the lower part of the packed bed 4 is provided. The transfer pipe 8 is preferably arranged vertically along the central axis of the reaction processing tank 2. A first opening 8 a made up of one or a plurality of holes is formed on a side surface of a portion of the transfer pipe 8 located below the packed bed 4. Furthermore, a second opening 8b made of a single or a plurality of holes is formed on the side surface of the portion of the transfer pipe 8 that protrudes above the filling layer 4. Although the first and second openings 8a and 8b are not particularly limited, it is preferable that about four are formed side by side in the circumferential direction of the transfer pipe 8. In addition, the upper end of the transfer pipe 8 is closed to form a collision wall 8c.
A cone-shaped umbrella member 12 whose top is directed upward is attached to the outer peripheral wall slightly above the first opening 8 a of the transfer pipe 8.

(Fluid supply means)
Furthermore, the treatment apparatus A for fluorine-containing water supplies air as a fluid from the lower part of the transfer pipe 8, and serves as a fluid supply means for generating an upward air jet (fluid flow) in the transfer pipe 8. Air supply means 10 is provided. The air supply means 10 is provided in the middle of the pipe 10b, an air supply device 10a that generates an air jet, a pipe 10b that communicates with the air supply device 10a and guides the generated air jet into the transfer pipe 8. And a valve 10c. The valve 10c is provided by closing the flow path in the pipe 10b, and the valve 10c is used to interrupt the supply of air from the air supply device 10a into the transfer pipe 8 or to adjust the supply amount of air. be able to.
It is more preferable that the air supply device 10a is provided with output control means capable of controlling the flow rate of the generated air jet appropriately.

  The other end 10 d of one end of the pipe 10 b communicating with the air supply device 10 a enters the transfer pipe 8 from the lower end of the transfer pipe 8 and opens upward in the transfer pipe 8. The other end 10d of the pipe 10b is arranged to be positioned above the first opening 8a.

(Separation means)
A separation tank 14 is provided on the upper end side of the transfer pipe 8. The separation tank 14 is formed in a cylindrical shape, and is disposed so as to surround the upper end portion of the transfer pipe 8 so that the second opening 8b of the transfer pipe 8 is located inside.
Further, the separation tank 14 is disposed so that the bottom surface thereof is in contact with the top surface of the packed bed 4. In other words, the packed bed 4 is formed in the reaction processing tank 2 by adjusting the amount of the granular material so that the upper surface thereof is in contact with the bottom surface of the separation tank 14.

  In the separation tank 14, a cylindrical gas-liquid separation wall 16 provided coaxially with a predetermined gap from the wall of the separation tank 14 is provided. The lower end of the gas-liquid separation wall 16 is provided so as to be slightly separated from the bottom surface of the separation tank 14.

  An opening 14 a is formed in the peripheral wall of the separation tank 14. A tubular drainage channel 18 communicates with the opening 14a. The drainage channel 18 extends outward from the reaction treatment tank 2 and penetrates the outer peripheral wall of the reaction treatment tank 2.

In addition, a water collecting trough 20 is provided along the inner peripheral wall of the separation tank 14. The catchment tank 20 reaches the predetermined water level (the upper end of the catchment tank part 20) in the separation tank 14, and guides the water (treated water) overflowing into the catchment tank part 20 to the drainage channel 18. It is provided as follows.
The water collecting unit 20 is provided coaxially between the wall of the separation tank 14 and the gas-liquid separation wall 16 with a predetermined interval therebetween. Further, the upper end of the water collecting basin 20 is provided to extend upward from the lower end of the gas-liquid separation wall 16.

  Further, an opening (passage port 14b) is formed on the bottom surface of the separation tank 14, and the particulate matter 22 in the separation tank 14 is configured to flow onto the packed bed 4 through the passage port 14b. The particulate matter 22 that has flowed onto the packed bed 4 through the passage port 14 b newly forms the packed bed 4.

(Particle supply means)
In the separation tank 14, a level sensor 24 is provided as a detecting means for detecting the amount of the granular material 22 accumulated in the separation tank 14. When the level sensor 24 detects that the particulate matter 22 in the separation tank 14 has become less than a predetermined amount, a control unit (not shown) linked to the level sensor 24 detects a particulate matter supply device (not shown). And the particulate matter is discharged from the particulate matter supply port 26 provided in the separation tank 14, and the particulate matter is supplied into the separation tank 14.
As the level sensor 24, a contact sensor, an infrared sensor, or the like can be employed.

  Next, the operation and action of the fluorine-containing water treatment apparatus A according to the present embodiment and the fluorine-containing water treatment method using the fluorine-containing water treatment apparatus A will be described.

  When fluorine-containing water (fluorine-containing wastewater) is supplied from the raw water supply pipe 6 by the transport pump into the reaction treatment tank 2 in which the packed bed 4 is formed, the fluorine-containing water passes through the packed bed 4, The fluorine component in the fluorine-containing water reacts with the granular calcium carbonate constituting the packed bed 4. By this reaction, a film made of water-insoluble calcium fluoride is formed on the surface of the granular material, and the fluorine component is removed from the fluorine-containing water. Then, the fluorine-containing water becomes treated water from which the fluorine component has been substantially removed when it reaches the lower part of the packed bed 4 while the fluorine component has a lower concentration while penetrating below the packed bed 4.

When the fluorine-containing water treatment apparatus A performs the treatment, the fluorine-containing water is supplied from the raw water supply pipe 6 and the air supply apparatus 10a is driven to move the air jet flow upward in the transfer pipe 8. Is generated.
Here, since the end portion 10d of the pipe 10b from which air is discharged is disposed above the first opening 8a, a negative pressure is generated inside the lower end portion of the transfer pipe 8. . Due to this negative pressure, the treated water from which the particulate matter and fluorine component in the lower part of the packed bed 4 have been removed is sucked from the first opening 8a, and is transported by the air jet at high speed in the transfer pipe 8 upward. Is done. And this granular material and treated water collide with the collision wall 8c which has block | closed the upper end part of the transfer pipe 8, and are ejected in the separation tank 14 from the 2nd opening part 8b.

Here, the granular material moves in the transfer pipe 8 at a high speed and collides with each other, or collides with the collision wall 8c, the inner peripheral wall of the transfer pipe 8, and the gas-liquid separation wall 16. By the impact, the calcium fluoride film formed on the surface of the granular material is crushed and removed.
In addition, it is preferable to form a metal-like unevenness on the inner surface of the collision wall 8c or on the inner peripheral wall of the transfer tube 8 because the collided granular film is more easily broken.

  Then, the particulate matter 22 ejected from the second opening 8 b into the separation tank 14 falls downward and accumulates in the separation tank 14.

  In this way, the granular material below the packed bed 4 is transferred upward, so that the packed bed 4 always flows downward. And the granular material 22 collected in the separation tank 14 is supplied to the upper part of the packed bed 4 through the passage port 14b. Since the granular material supplied from the inside of the separation tank 14 is obtained by removing the calcium fluoride film, the granular material highly reactive with the fluorine component is always supplied to the packed bed 4.

  On the other hand, the treated water ejected from the second opening 8b into the separation tank 14 accumulates in the separation tank 14 and overflows into the catchment basin 20, and is separated from the drainage channel 18 into the separation tank 14 and the reaction treatment tank 2. Is discharged outside.

  At this time, the calcium fluoride film scraps (calcium fluoride pieces) removed from the particulate matter are discharged together with the treated water and discharged from the drainage channel 18 because the particle size is small.

The magnitude | size of the calcium fluoride piece discharged | emitted with a treated water can be set with the shape and arrangement | positioning of the gas-liquid separation wall 16 and the water collecting basin part 20. FIG. That is, if the interval between the water collecting basin 20 and the gas-liquid separation wall 16 is set narrower, the flow rate of the treated water flowing into the water collecting basin 20 is increased, so that larger waste (calcium fluoride piece) ) Will also be discharged. Further, if the difference in height between the upper end of the water collecting basin 20 and the lower end of the gas-liquid separation wall 16 is made smaller, the solid matter in the treated water can easily flow into the water collecting basin 20 and larger debris (flood) Even calcium fluoride pieces) are discharged.
Usually, it is preferable to set the shape and arrangement of the gas-liquid separation wall 16 and the water collecting trough 20 so that calcium fluoride pieces having a diameter of approximately 0.5 mm or less in the treated water are discharged. As a result, the calcium fluoride film peeled off from the granular material and the excessively small granular material are almost discharged, and the granular material having a size suitable for constituting the packed bed 4 is stored in the separation tank 14. Can be recycled to the packed bed 4.

While the fluorine-containing water treatment apparatus A performs the treatment of the fluorine-containing water, the particle size of the granular material is gradually reduced by removing the calcium fluoride film.
In this state, the volume of the packed bed 4 is reduced and the fluorine component cannot be sufficiently removed, and the amount of the particulate matter 22 staying in the separation tank 14 is reduced, so that the upper surface of the packed bed 4 is separated. A gap is formed between the tank 14 and the passage port 14b, and the fluorine-containing water supplied from the raw water supply pipe 6 enters the separation tank 14 from the passage port 14b into the reaction treatment tank 2 and remains untreated. There arises a problem that the water is drained from the drainage channel 18.

In view of this, in the treatment apparatus A for fluorine-containing water, a granular material supply means is provided. As described above, when the control unit detects that the granular material 22 in the separation tank 14 is less than a predetermined amount due to the detection state of the level sensor 24, the granular material supplying device (Not shown) is driven to release the granular material from the granular material supply port 26 provided in the separation tank 14 to supply the granular material into the separation tank 14.
Since the particulate matter supply means always maintains a predetermined amount or more of the particulate matter in the separation tank 14, the reduction of the packed bed 4 can be prevented, and the upper surface of the packed bed 4 and the passage port 14 b of the separation tank 14 can be prevented. It is possible to prevent the fluorine-containing water from being discharged untreated by being filled with particulate matter.
Note that the amount of the particulate matter retained in the separation tank 14 is preferably about 10% of the amount of the particulate matter in the packed bed 4.

  The umbrella member 12 is provided to reduce the pressure applied to the portion around the second opening 8b of the filling layer 4 due to the weight of the filling layer 4 itself. Without the umbrella member 12, a large pressure is applied to the lower portion of the packed bed 4 to become dense, the fluidity is lowered, and the particulate matter constituting the packed bed 4 is not smoothly sucked into the first opening 8a. End up. When the umbrella member 12 receives pressure applied to the packed bed 4 around the first opening 8a, the pressure under the packed bed 4 is reduced, and the flowability of the granular material is improved, so that the first opened portion smoothly. It can flow into 8a.

  In addition, the moving speed (moving volume per hour) of the fluorine-containing and water particulates moving downward in the reaction treatment tank 2 is such that the moving speed of the fluorine-containing water is about 5 times the moving speed of the granular materials. Further, it is preferable to adjust the flow velocity of the air jet, the inner diameter of the transfer pipe 8, the size of the first opening 8a, and the like.

  According to the treatment apparatus A for fluorine-containing water and the treatment method using the same according to the present embodiment, even when treating high-concentration fluorine-containing water, the particulate matter is not interrupted without interrupting the fluorine component removal treatment. By removing the calcium fluoride film formed on the surface, the surface of the granular particles can be maintained in a highly reactive state with the fluorine component, and the processing efficiency is very high. Further, such an effect can be realized with a compact, simple and inexpensive configuration.

  Further, if the treatment is performed with the treatment apparatus A of the present fluorine-containing water, the particle diameter of calcium fluoride in the treated water is increased and the free fluorine concentration is lowered as compared with the conventional treatment method using slaked lime. Therefore, an apparatus that performs aggregation and solid-liquid separation in this downstream process can be configured to be simple and small.

  Next, more specific examples of the fluorine-containing water treatment apparatus A according to the present embodiment and the results of the implementation will be described.

In the fluorine-containing water treatment apparatus A, the effective filling volume of the packed bed 4 was 200 L, and 2 mm diameter calcium carbonate particles were employed as the granular material. Then, the fluorine-containing water prepared by mixing hydrofluoric acid concentrate and tap water to adjust the fluorine concentration to 1,000 to 1,300 mg / L is a space velocity of 5 / h (5 times the effective filling volume per hour. In the example, it was supplied to the reaction treatment tank 2 at 1,000 L / h), and air was supplied at a flow rate of 18 m ³ / h by the air supply means 10 to treat the fluorine-containing water continuously for 25 hours. . Further, along with the treatment of the fluorine-containing water, the calcium carbonate particles were replenished by the granular material supply means.

The treated water that has been treated under the above conditions and discharged from the drainage channel 18 is stored in a tank, an inorganic flocculant (polyaluminum chloride liquid PAC) is added at a concentration of 600 mg / L, and the polymer flocculant liquid is added. 2 mg-polymer / L was added to coarsen calcium fluoride and separate by settling.
When the fluorine concentration of this treated water (supernatant liquid) was analyzed, it was 5.8 mg / L.
On the other hand, when the settled slurry was pulled out and pressure dehydrated on the filter paper, the moisture content of the sludge was 42%. The sludge was dried at 110 ° C for 2 hours and analyzed for composition.
Ca content: 510,000mg / kg-dry
F min: 420,000mg / kg-dry
The value of was obtained. From this, it was estimated that 86% CaF ₂ was contained in the sludge.

In addition, after the treatment with fluorine-containing water is stopped, the composition of the calcium carbonate particles 22 in the separation tank 14 is analyzed, and the residual amount of fluorine after the removal of the calcium fluoride film by collision with the collision wall 8c and the like is examined. Where
F Residue: 1,500mg / kg-dry
(The granular material supply device was stopped before collection so that the calcium carbonate particles newly collected by the granular material supply means were not mixed with the collected calcium carbonate particles). From this, it was estimated that 3,100 mg / kg-dry (0.3%) of CaF ₂ remained in the calcium carbonate particles after removal of the calcium fluoride film.

  From these experimental results, calcium carbonate contributes to the reaction almost without waste, and the surface of calcium carbonate particles is sufficiently peeled off and removed, and the state of high reactivity is always maintained. There was found.

  Next, Example 2 will be described. Note that description of the same conditions as those in the first embodiment is omitted.

Fluorine-containing water adjusted to a fluorine concentration of 3,300 mg / L is supplied to the reaction treatment tank 2 at a space velocity of 3 / h (that is, 600 L / h in this example), and 54 m ³ / h by the air supply means 10. Air was supplied at a flow rate to treat the fluorine-containing water continuously for 2 hours.

The treated water that has been treated under the above conditions and discharged from the drainage channel 18 is stored in a tank. After adding an inorganic flocculant (polyaluminum chloride liquid PAC) at a concentration of 600 mg / L and stirring, the polymer flocculant liquid is added. 3 mg-polymer / L was added to coarsen calcium fluoride and separate by settling.
It was 5.9 mg / L when the fluorine concentration of this treated water (supernatant liquid) was analyzed.
On the other hand, the sedimented slurry was pulled out and pressure dehydrated on the filter paper, and the moisture content of the sludge was 36%.

In addition, after the treatment with fluorine-containing water is stopped, the composition of the calcium carbonate particles 22 in the separation tank 14 is analyzed, and the residual amount of fluorine after the removal of the calcium fluoride film by collision with the collision wall 8c and the like is examined. Where
F Residue: 12,000mg / kg-dry
The value of was obtained. From this, it was estimated that 25,000 mg / kg-dry (2.5%) of CaF ₂ remained in the calcium carbonate particles after removal of the calcium fluoride film.

  From these results, it was found that the fluorine-containing water treatment apparatus A according to the present embodiment is capable of continuous treatment even for high-concentration fluorine-containing water having a fluorine concentration of about 3,000 mg / L.

(Comparative Example 1)
A comparative experiment was conducted using an intermittent regeneration type packed tower having an effective packed volume of 20 L having the structure disclosed in Patent Document 1.
Fluorine-containing water mixed with hydrofluoric acid concentrate and tap water to adjust the fluorine concentration to 1,000 mg / L is supplied to the packed tower at a space velocity of 5 / h (ie, 100 L / h in this example). The water flowed downward.

  When the pH of the liquid passing through the packed tower was measured, the pH dropped to 5 or less when about 5 hours had passed after the start of water flow. After collecting the passing liquid and filtering using No. 5C filter paper, the fluorine concentration in the filtrate was measured. The value immediately after the start of water flow was 12 mg / L, and the value after 5 hours was 28 mg / L. Thus, it has been found that the reactivity of the packed tower decreases from 5 hours after the start of water flow.

At this point, the supply of fluorine-containing water is stopped, tap water is flowed upward, and the filler is polished by rotating the stirring blade installed at the top of the packed tower while pressing at a linear velocity of 40 mm / s. Drained through strainer. This regeneration process was performed for 120 seconds.
When the amount of fluorine remaining on the filler surface was analyzed,
F Residue: 15,000mg / kg-dry
The value of was obtained. From this, it was estimated that 31,000 mg / kg-dry (3%) of CaF ₂ remained in the calcium carbonate particles after the surface was polished with the rotation of the stirring blade.

When the fluorine-containing water was passed again after the regeneration treatment, the pH value decreased to 5 or less 2 hours after the start of the water flow.
From these results, when treating relatively high concentrations of fluorine-containing water, the intermittent regeneration method requires frequent stoppage and regeneration of the raw water supply (at least every 2 hours after the second time). It has been found.

(Comparative Example 2)
The same fluorine-containing water used in Example 1 was treated by a treatment method using slaked lime, and a comparative experiment was performed.
Slaked lime slurry was added to fluorine-containing water (1,000 mg / L) to adjust to pH 10, and the mixture was stirred for 60 minutes for reaction. After the reaction, PAC was added at a concentration of 600 mg / L and stirred, and then sulfuric acid was added to adjust the pH to 7. Further, 2 mg-polymer / L of a polymer flocculant was added to coarsen calcium fluoride and separate by precipitation.
When the fluorine concentration of the treated water (supernatant liquid) was analyzed, it was 12 mg / L.
On the other hand, when the sedimented slurry was pressure dehydrated on filter paper, the moisture content of the sludge was 74%. The sludge was dried at 110 ° C for 2 hours and analyzed for composition.
Ca content: 520,000mg / kg-dry
F min: 380,000mg / kg-dry
The value of was obtained. From this, it was estimated that 78% of CaF ₂ was contained in the sludge.
From this experimental result, the conventional fluorine-containing water treatment method using slaked lime slurry has a higher fluorine concentration in treated water and a higher water content of sludge than the calcium carbonate packed tower method. It turned out that the amount would increase.

  The treatment apparatus and treatment method for fluorine-containing water of the present invention are not limited to the use of treating fluorine-containing wastewater generated by semiconductors, liquid crystals, crystal processing, etc., and are intended to remove fluorine components from fluorine-containing water. If it is, it can be applied to all uses.

It is side explanatory drawing which shows the structure of the processing apparatus of fluorine-containing water which concerns on this Embodiment. It is plane explanatory drawing which shows the structure of the processing apparatus of fluorine-containing water which concerns on this Embodiment. It is explanatory drawing which shows the structure of the processing apparatus of the conventional fluorine-containing water.

Explanation of symbols

A treatment apparatus for fluorine-containing water 2 reaction treatment tank 4 packed bed 6 raw water supply pipe 8 transfer pipe 8a first opening 8b second opening 8c collision wall 10 air supply means (fluid supply means)
DESCRIPTION OF SYMBOLS 10a Air supply apparatus 10b Pipe 12 Umbrella member 14 Separation tank 14a Opening part 14b Passage port 16 Gas-liquid separation wall 18 Drainage channel 20 Catchment part 22 Granules (calcium carbonate particle)
24 Level sensor 26 Granule supply port

Claims (6)

Fluorine-containing water is passed through a reaction treatment tank in which a packed bed composed of a granular material mainly composed of calcium carbonate is formed, and water-insoluble due to the reaction between the fluorine component in the fluorine-containing water and calcium carbonate in the granular material. In a fluorine-containing water treatment apparatus that forms a film made of calcium fluoride on the surface of a granular material and removes a fluorine component from fluorine-containing water,
A cylindrical body extending upward from the lower part in the reaction treatment tank, wherein the first opening part is opened on the side surface of the part located at the lower part of the packed bed, and the part is located above the upper surface of the packed bed. A transfer pipe formed with an opened second opening;
An upward fluid flow is generated in the transfer pipe, and treated water from which particulate matter and fluorine components in the lower part of the packed bed sucked into the transfer pipe from the first opening are removed is transferred to the transfer pipe. The calcium fluoride coating formed on the surface of the granular material transferred to the upper direction is crushed and removed by collision with the granular materials and the inner wall of the transfer pipe, and is removed from the surface of the granular material and the granular material. Fluid supply means for supplying fluid into the transfer pipe so as to discharge the calcium fluoride pieces and the treated water from the second opening,
The particulate matter and the treated water are separated to return the particulate matter discharged from the second opening to the packed bed and to discharge the treated water discharged from the second opening to the outside of the reaction treatment tank. The fluorine-containing water treatment apparatus is characterized by comprising a separating means. A collision wall provided by closing the upper end of the transfer pipe and crushing and removing the calcium fluoride film formed on the surface of the granular material when the granular material transferred through the transfer pipe collides. With
The apparatus for treating fluorine-containing water according to claim 1, wherein the second opening is formed on a side surface of the transfer pipe.   The fluid supply means supplies the fluid upward in the transfer pipe from a position above the first opening, thereby generating a negative pressure inside the lower part of the transfer pipe, The apparatus for treating fluorine-containing water according to claim 1 or 2, wherein the granular material and the treated water are sucked into the transfer pipe from the opening. The separating means includes
A cylindrical body in which the second opening of the transfer pipe is located, the bottom surface is disposed so as to contact the top surface of the packed bed, and the bottom surface is discharged from the second opening and is separated by the separating means. A separation layer in which a passage port for returning the calcium fluoride pieces and the granular material separated and collected from the treated water to the packed bed is formed;
It has the drainage channel which discharges the calcium fluoride piece and the treated water which were discharged from the second opening and separated from the particulate matter from the separation tank. The apparatus for treating fluorine-containing water according to any one of the above.   The apparatus for treating fluorine-containing water according to claim 4, further comprising a granular material supply means for supplying the granular material into the separation layer when the granular material accumulated in the separation tank becomes less than a predetermined amount. .   A method for treating fluorine-containing water, wherein the fluorine-containing water treatment apparatus according to any one of claims 1 to 5 is used to remove a fluorine component in fluorine-containing water.

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