JPS61192385A - Treatment of fluorine-containing waste solution - Google Patents

Abstract

PURPOSE:To efficiently treat an eluate by adding calcium salt to said eluate, by applying adsorbing treatment to a waste solution of which the pH was adjusted to 7 or less and subsequently regenerating an adsorbent by using an alkaline solution with pH of 10 or more. CONSTITUTION:A fluorine-containing waste solution (a) is supplied to a storage tank 1 wherein the pH thereof is adjusted to 5 and subsequently sent to an adsorbing tower 2 packed with an adsorbent and fluorine is adsorbed to obtain treated water (b). When the fluorine content of treated water (b) reached a certain set value, the adsorbing tower 2 is transferred to a desorptive regeneration process from the adsorbing process and an alkaline solution (c) with pH of 10 or more is sent to the adsorbing tower 2 and adsorbed fluorine is desorbed to form an eluate (d). The eluate (d) is sent to a sedimentation tank 3 held to pH of 12 or more and calcium hydroxide is added to said tank 3 to form a calcium fluoride precipitate. The precipitate is sent to a sedimentation tank 4 and calcium fluoride is taken out of the system.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for removing waste liquid containing fluorine and fluorine compounds, and in particular, when adsorbing and regenerating using an adsorbent, the regenerated liquid is collected, The purpose is to provide a closed adsorption/regeneration system through recycling.

(Prior art) In recent years, the use of fluorine and its compounds has increased, and they are widely used in semiconductor manufacturing, the electronic industry such as cleaning the inner surfaces of cathode ray tubes, the metal industry such as aluminum manufacturing, the chemical industry, and the ceramic industry. Fluorine remains in the wastewater as compounds such as fluorine ions or fluorine complex ions, and the fluorine concentration in the wastewater can reach several hundred ppm at one time.

Currently, the fluorine concentration in wastewater discharged into public water bodies is regulated to 15 ppm or less from the perspective of environmental conservation and pollution prevention, and on the other hand, some local governments are trying to regulate wastewater standards even more strictly. Establishment of advanced processing technology is desired.

A commonly used method for removing fluorine and fluorine compounds from waste liquid is to use calcium salts such as slaked lime or calcium chloride, and to precipitate and separate calcium fluoride with low solubility. However, calcium fluoride has some solubility in water, and fluorine is similar to silicon in wastewater.

It is easy to form complex ions with iron, aluminum, etc., and it is very difficult to separate the fluorine, making it difficult to keep the fluorine concentration below the wastewater standard value. The current situation is that

In addition, fluoride ions are adsorbed using activated alumina.
A method has also been proposed in which fluorine ions are reacted with silicon, aluminum, iron, or zirconium to form complex ions, and then adsorbed and removed using an anion exchange resin.

(Problems to be Solved by the Invention) When using these adsorbents, there is the problem of how to treat the eluent with a high fluorine concentration generated during regeneration of the adsorbent, and this point has not yet been studied. do not have.

(Means to Solve the Problem) In order to solve this problem, the inventors of the present invention have conducted intensive studies on an adsorption/regeneration system that efficiently removes fluorine and/or fluorine compounds from waste liquid. , we have arrived at the present invention.

To explain the present invention, the present invention converts fluorine and/or fluorine compounds in waste liquid into Ti, Zr.

In the case of removal treatment using lanthanide or actinide metal hydrated oxides or metal hydrated fluorides,
After adjusting the pH of the waste liquid to 7 or less and performing adsorption treatment, and then regenerating the adsorbent using an alkaline solution, fluorine and/or fluorine compounds in the eluent are removed by adding a calcium salt to the eluent. The present invention relates to a method for treating fluorine-containing waste liquid, which is characterized by separating it by precipitation as a calcium compound.

To explain the present invention in more detail, 5 In the present invention, fluorine and fluorine compounds in waste liquid are removed using an adsorbent made of hydrated metal oxides or hydrated fluorides of Ti, Zr, rare earth elements, or actinides. Perform the removal process. Here, the rare earth elements are Y, La,
Oe%Pr, Nd, Pm, 8m%Eu.

Gd, Tb, Dy, Ho, Er, Tm, -Y
b and Lu, and actinide is Th%Pa,
UlNp, Pu, Am, Cm, Bk.

Of, Es, Fm, Md, No and Lr. In the present invention, Ti and Zr are further used, and these metals may be used alone or in a mixture of two or more. These famous hydroxides are often in the form of cakes or particles with a size of several tens of microns or less.

As it is, it is difficult to handle it engineeringly. Therefore, it is preferable to handle these hydrous oxides by supporting them on a suitable porous carrier, and various inorganic and organic materials can be used, but in particular, support strength, chemical durability,
Organic polymer materials are preferred in terms of mechanical durability and the like.

Examples of organic polymer materials include fluorine resins, vinyl chloride resins, styrene resins, polyamide resins, polyester resins, polysulfone resins, polyimide resins, methacrylic resins, polyacrylonitrile, and olefin resins.
Examples include vinyl alcohol copolymers.

The method for supporting the above hydrous oxide on an organic polymer material is as follows:
Various known methods can be applied. For example, there is a method in which particles of the hydrous oxide are suspended and dispersed in a solution containing a suitable polymeric material, and formed into particles using water as a coagulation bath, or a method in which an appropriate monomer is added to the particles of the hydrous oxide. There are methods such as emulsification or suspension polymerization to form particles in the presence of a porous oxide. Any method may be used as long as it can be achieved.

Conventionally known methods can be used to bring the above-mentioned granular adsorbent into contact with waste liquid containing fluorine and fluorinated foods, and in particular, methods such as fixed bed method, fluidized bed method, and moving bed method can be used. The technique is suitable for carrying out adsorption-desorption regeneration operations.

The metal hydrated oxide or metal hydrated fluoride used in the present invention is an amphoteric ion exchanger, and shows a tendency to completely adsorb anions on the acidic side and cations on the alkaline side. For example, when using the hydrous cerium oxide sound of the present invention, the relationship between adsorption performance of various ions and pH is as shown in Figure 1.
It can be seen that the adsorption performance for fluorine ions and hexafluorosilicate ions is particularly high on the acidic side. Therefore, the adsorbent used in the present invention can be used in waste liquid.

Even if fluorine is present in the form of fluorine ions or fluorine complex ions, it has excellent adsorption performance.

Here, the fluorine complex ions present in the waste liquid include hexafluorosilicate ion, borofluoride ion, hexafluoroaluminium ion, hexafluoroiron ion,
Examples include hexafluorotitanium ion and hexafluorozirconium ion, and these may be used alone or two or more types may be dissolved in water. Among them, fluorine often exists as a hexafluorosilicate ion,
For example, when using the hydrous cerium oxide solution of the present invention, it exhibits excellent adsorption performance at pH 7 or lower, similar to that for fluorine ions.

However, hexafluoroaluminum ions, hexafluorotitanium ions, and the like are dissociated 9 due to pH changes, and in some cases, precipitation may occur, so it is difficult to determine the exact adsorption amount of each complex ion. Since the adsorbent of the present invention has excellent adsorption performance even when fluorine ions and fluorine complex ions coexist, it can also exhibit excellent effectiveness in the adsorption treatment of fluorine complex ions as described above. can.

In the adsorption step in the present invention, after the pH of the waste liquid is set to 7 or less, which is a preferable condition for adsorption of fluorine and fluorine compounds by the hydrous oxide, the waste liquid is brought into contact with the hydrous oxide to remove fluorine and/or fluorine compounds in the waste liquid. Let it absorb.

The temperature of the adsorption operation described above affects the adsorption rate, and heating is effective. However, it has a practically sufficient speed even at room temperature, and 5~9o''C1 is practically 20~
A range of 60°C is preferred. In addition, the contact time depends on the contact method and the type of adsorbent, but usually it takes about 1 minute to 3 days for the amount of adsorption to reach saturation, but practically it takes 1 minute to 60 minutes. That's fine. These temperature and time conditions are
It can also be applied to detachment and regeneration operations, which will be described later.

Further, the adsorbent used in the present invention that has adsorbed fluorine and/or fluorine compounds can be brought into contact with an alkaline solution to desorb fluorine and/or fluorine compounds, and can be repeatedly subjected to adsorption operations. The desorption rate depends on the concentration of fluorine and/or fluorine compounds adsorbed on the adsorbent, the pH and temperature of the alkaline solution. In particular, the influence of the pH of the alkaline IJ iW solution is large, and as can be seen from Figure 1, the pH of the alkaline solution is 10
If it is more than 12, it can be detached, but it is preferably 12 or more, more preferably 13 or more.

In the above desorption operation, inorganic alkalis such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, and organic amines can be used as the alkaline aqueous solution. Sodium hydroxide and potassium hydroxide are particularly preferred because of their high desorption efficiency.

・The amount of alkali required for desorption of fluorine (and/or fluorine compounds) is 1.3 times the equivalent for fluorine ions, and 1.3 × m times the equivalent for fluorine compounds (MP"'), which is 100%. Therefore, the higher the pH of the alkaline solution, the greater the concentration of fluorine and/or fluorine compounds in the eluent, and the easier it is to recover the alkaline solution from the eluent. Become.

Furthermore, when these alkaline solutions are brought into contact with an adsorbent that has adsorbed fluorine and/or fluorine compounds, fluorine and/or fluorine compounds are desorbed by an ion exchange reaction, and the eluate after desorption is neutralized and the pH decreases. do.

In the present invention, by removing fluorine and/or fluorine compounds in the solution 111II as precipitation of poorly soluble calcium compounds, wastewater containing high concentrations of fluorine and/or fluorine compounds is removed from the wastewater treatment system. A major feature is that it can provide a closed processing system that does not release any waste.

Fluorine in the eluent and/-! In order to separate and remove the bamboo fluorine compound as a precipitate of a poorly soluble calcium compound, it is sufficient to add at least twice the equivalent of fluorine as calcium, preferably 2 to 4 times the equivalent. If the amount added is less than 2 times equivalent, the removal efficiency of the precipitate as a calcium compound will be low, and if it exceeds 4 times equivalent, the removal efficiency will hardly change, resulting in an economic disadvantage. The pH of the eluent when removing sediment is preferably 6 or higher, and as described later, when recovering an alkaline solution from the eluate, the pH is maintained at 12 or higher, preferably 13 or higher. If the pH at the time of precipitation treatment is lower than 6, the solubility of the calcium compound will increase and the precipitation separation efficiency will decrease.
If it is less than 2, the efficiency of alkali recovery becomes low, which is not preferable.

Furthermore, when fluorine and/or fluorine compounds in the eluent are precipitated and removed as calcium compounds, aluminum sulfate or phosphate can be present in addition to calcium ions. The efficiency of precipitation separation of fluorine compounds can be increased.

Here, as conditions for precipitation separation, the reaction time is 10
The reaction temperature should be at least 1 minute, and the reaction temperature is sufficiently fast at around room temperature.
There is no need to particularly heat it. Furthermore, in order to increase the efficiency of sedimentation separation, it is also preferable to add a known polymer flocculant.

The precipitated eluate may contain fluorine and/or fluorine compounds at a fluorine concentration of approximately 81) pm, or even several tens of ppm in some cases, and cannot be flushed away as wastewater.

Therefore, if the amount of the precipitated eluate is small, it can be returned to the adsorption process9, diluted and discharged as wastewater, or used as make-up water for the alkaline solution for desorption. The most preferred method is to recover the alkaline solution for desorption regeneration of the adsorbent when fluorine and/or fluorine compounds in the eluent are separated by precipitation.

In order to recover the alkaline solution, the pH of the eluent must be adjusted to 12.
The above value is preferably kept at 13 or more, and calcium hydroxide is added in an amount equivalent to 2 to 4 times the amount of fluorine in the eluent. If the pH of the eluent is less than 12, the efficiency of recovering the alkaline solution will be low. The pH of the eluent can be maintained at 12 or higher due to the solubility of calcium hydroxide;
If it is desired to increase the amount above, an inorganic alkali such as sodium hydroxide or potassium hydroxide may be added. These inorganic alkalis, which are used to keep the pH of the eluent above 13, only need to be added once at the beginning and can be recovered afterwards. Therefore, calcium hydroxide can be used not only as a calcium source but also as an adsorbent. It can also be used as an alkali source for regeneration, making it economically advantageous.

For example, when fluorine is present in the eluent as sodium fluoride, a highly concentrated alkaline solution can be recovered according to the following reaction.

2NaF+0a(OH)2-+2NaOH+0aP1↓
This reaction proceeds efficiently at a pH of 12 or higher, preferably at a pH of 12 or higher.
It is H13 or higher.

The alkaline solution recovered here contains fluorine equivalent to the solubility of the fluoride to be separated by precipitation, and the fluorine concentration is normally about 20 ppm, but the fluorine concentration in the eluent is as high as several thousand ppm. Therefore, there is no adverse effect on the efficiency of desorption and regeneration. As described above, the adsorption/desorption regeneration system of the present invention is characterized in that it does not produce high-concentration fluorine-containing waste liquid and can be extracted from the system as calcium compounds.The calcium compounds are used as raw materials for fluorine production. It is also possible to use it as

The recovered alkaline solution contains calcium ions equivalent to the solubility of calcium fluoride, so if it is brought into contact with an adsorbent that has adsorbed fluorine, metal fluoride will precipitate at that point, so please be careful when handling the alkaline solution. Not good. Therefore, it is necessary to treat the recycled alkali solution in advance so that the concentration of calcium ions is lower than the solubility of calcium fluoride.

Although known methods can be applied to this method, one preferred example is to bring an alkaline solution into contact with a cation exchanger. Furthermore, T used here as a fluorine adsorbent
I + Z r s Metal hydrated oxides or wire mesh fluorides of lanthanides or actinides are 5-zwitter ion exchangers and can adsorb calcium ions in the alkaline region, so the same adsorption as used for fluorine adsorption agents can be used.

Next, the adsorbent that has been desorbed and regenerated by contacting with an alkaline solution has a low pH, and cannot fully demonstrate its original adsorption performance even if it is directly subjected to the trench adsorption process. The pH of the adsorbent can be brought to an acidic to neutral range by washing with water or diluted acid. Generally, hydrochloric acid of 0.001N to IN,
A method of contacting with an acid such as #L acid or nitric acid is used.

If the method described above is used, repeated adsorption is possible.

It is possible to perform desorption and desorption, making it a closed and efficient treatment system for fluorine-containing waste liquid.

Next, an embodiment of the method of the present invention will be described based on the drawings. Although FIG. 5 is an example of a system for implementing the present invention, the method of the present invention is not limited thereby. In FIG. 5, the fluorine-containing waste liquid a is stored in storage tank 1.
After adjusting the pH to 5, the water is sent to an adsorption tower 2 filled with an adsorbent, where fluorine is adsorbed and a treated water solution is obtained. When the fluorine concentration in the treated water reaches a certain set value (breakthrough point), the process moves from the adsorption process to the desorption and regeneration process, sending alkaline solution C with a pH of 10 or higher to the adsorption tower 2, desorbing and eluting the adsorbed fluorine. Let it be liquid d. The pH of eluent d is 6 to 7, and the fluorine concentration is 2,000 to 3. o o o ppm.

The eluent d is sent to a sedimentation chamber 3 maintained at %I) H12 or higher, where calcium hydroxide is added to form a calcium fluoride sediment. The generated sediment is sent to the sediment separation tank 4, and calcium fluoride is taken out of the system. Here, the raised liquid e from the sedimentation separation tank 4 is an alkaline liquid with a pH of 12 or higher and contains calcium ions, so the adsorption tower 5 is filled with the same adsorbent as that filled into the adsorption tower 2. An alkaline solution is passed through the tube to reduce the calcium ion concentration to several ppm or less, and then recovered.

Furthermore, in the present invention, if it is desired to continuously perform the treatment of fluorine-containing waste liquid (=15-), it is possible to use two or more fluorine adsorption towers and operate the adsorption and desorption regeneration steps by switching between them. In some cases, the method of the present invention can also be carried out by a multi-stage fluidized bed method, a moving bed method or a batch adsorption method.

(Effects of the Invention) Next, the characteristics of the method for treating fluorine-containing waste liquid of the present invention are as follows.

(1) Fluorine accumulated ions and fluorine complex ions in waste liquid can be efficiently removed.

(2) It is economical because the alkali for regenerating the adsorbent is recovered from the waste liquid containing high concentration of fluorine generated in the adsorbent regeneration process, and since fluorine is removed as a solid content, it is easy to handle. It is easily produced and can be reused as a raw material for fluorine.

(Example) Example 1 Hydrous cerium oxide of the present invention (commercial product, heat loss 15.2%)
- Average particle size of missing particles is 0.08μ, average particle size of aggregated particles is 4μ, X-ray diffraction figure 3a, infrared absorption spectrum figure 3b
An example of the pH dependence of adsorption performance for fluorine ions and hexafluorosilicate ions in Figure) is shown below.

Prepare a 2 mmot/L aqueous solution of hydrofluoric acid (special grade reagent) or hydrofluorosilicic acid (special grade reagent), mix the adsorbent into the aqueous solution at a ratio of 1f-adsorbent/lt,
Stirred. 0.0% to the mixed solution. IN sodium hydroxide aqueous solution was added to adjust the pH to the desired value. After 2 hours, the concentration of fluorine ions dissolved in the mixture was measured by ion chromatography (device 202OI model manufactured by Dlonex). The results are shown in FIG. 1 as the relationship between the pH of the solution and the removal rate of fluorine ions or hexafluorosilicate ions.

In addition, chloride ion and nitrate ion are used as reference examples.

FIG. 1 shows the results of a similar experiment with calcium ions and sulfate ions.

Example 2 A fluorine adsorbent was prepared in which hydrated cerium oxide of 0.3 f/-1 adsorbent was supported on a matrix of ethylene-vinyl alcohol copolymer with an ethylene content of 38 mol%, and this was used to adsorb fluorine. An example of the operation will be explained.

The above adsorbent 15- was packed in a column with a diameter of 10 φ, and hydrofluoric acid (special grade reagent) was used as 10011
The pH of the solution containing 1 v/d was adjusted to various values with an aqueous sodium hydroxide solution, and water was passed through the column at 20° C. and at a superficial velocity of 10 hr'. Fluorine concentration in treated water is lp
The amount of liquid passed through the adsorbent until it reached pm was determined, and the results are shown in Table 1.

Table 1 Adsorbent manufacturing method 1 Ethylene-vinyl alcohol copolymer (ethylene 38 molar ratio) was dissolved in dimethyl sulfoxide at a concentration of 11% by weight, and the solution was mixed with hydrated cerium oxide (commercial product, heat loss 15%).
2% - average particle size of charcoal particles 0.08 μm, average particle size of aggregated particles 0.4 μm) was added 4 times the weight of the polymer, and thoroughly stirred and dispersed to form a slurry IJ-form. The slurry was formed into granules using water as a coagulation bath.

Example 3 An example will be shown regarding the p)M nature of the desorption rate in a desorption operation using an alkaline solution.

In advance, fluorine ions and hexafluorosilicate ions were adjusted to 1.65 mmot/f- as the total fluorine adsorption amount.
Hydrous thorium oxide (thermal loss: 19%, average particle size of aggregated particles: 0.9 μm) adsorbed on the adsorbent is adsorbed onto a polyvinylidene fluoride adsorbent. Then, the adsorbent was heated to 0.
01 N~1. ON sodium hydroxide aqueous solution and 10f
- Adsorbent/1 t was mixed and stirred at 20° C. for 2 hours. After 2 hours, the pH and fluorine concentration of the mixed solution were measured. The results are shown in Table 2.

Table 2 shows an example in which the shredded adsorbent 15- was packed into a column with a diameter of 10 wφ and water was passed through it at a superficial velocity of 3 hr-'. As shown in FIG. 2, the average pH of the eluent was 6.7, the fluorine concentration was as high as 2,900 ppm, and the fluorine desorption rate was 100%.

Adsorbent manufacturing method 2 Thorium oxide (99%, reagent) is heated with llI sulfuric acid until white smoke appears, then distilled water is added to dissolve it, and 6N ammonia water is added to form a precipitate.

- After late ripening, it is washed in a case where sulfate ions and ammonium ions are no longer recognized, and dried at 50°C.

Adsorbent manufacturing method 3 Polyvinylidene fluoride was dissolved in dimethylformamide at a concentration of 10% by weight, and the above-mentioned hydrous thorium oxide was added to the solution by 4 times the weight of the polymer, and the mixture was thoroughly stirred and dispersed. The mixture was shaped into granules using water as a coagulation bath.

Examples 4-5 pH 6,7 obtained by column method desorption of Example 3
An example will be shown in which precipitation separation was performed by adding calcium ions using an eluent with a fluorine concentration of 2.9QQppm.

The amount of calcium chloride or calcium hydroxide added to the above eluent was changed and the mixture was stirred at 20° C. for 30 minutes to separate fluorine by precipitation. The results are shown in Table 3.

Table 3 Example 6 Example 30 pH 6,7 obtained by force ram desorption
Using an eluent with a fluorine concentration of 2,900 ppm,
An example of alkaline solution recovery is shown below.

The above eluent was stirred at 20° C. for 30 minutes at various pH values with varying amounts of calcium hydroxide added, and the composition of the recovered alkaline solution was measured. The results are shown in Table 4.

Examples 7-8 In order to remove calcium ions in the recovered alkaline solution obtained in Example 6-b, a commercially available cation exchange resin (
Using DOWEX 50WX2) and the same adsorbent used in Example 2, 1 m-adsorbent/10 ml
- The mixture was mixed at the same proportion as the recovered alkaline solution, mixed at room temperature for 10 minutes, and the calcium ions in the solution were measured. The results are shown in Table 5. Note that no changes in hydroxyl group and fluorine concentrations were observed.

Table 5 Example 9 Polyacrylonitrile matrix with 0.3 f/
An example is shown in which an adsorbent supporting yttrium fluoride hydrate, a Go adsorbent, was prepared and used to perform fluorine adsorption, regeneration operation, precipitation separation of fluorine in the eluent, and recovery of an alkaline solution.

The above adsorbent 15- was packed into a column with a diameter of 10 φ,
100 ppm of sodium fluoride as fluorine ion
The stock solution containing the liquid and adjusted to pH 3 at a superficial velocity of 3
Water was passed through the column under conditions of Q hr-1. As a result, the amount of treated liquid until the fluoride ion concentration at the outlet of Karajin reached 1 ppm was 120 times the amount of fluoride per 1 - adsorbent, and the amount of fluorine adsorbed at that time was 12 TIq/m/- adsorbent. Ta.

Next, the adsorbent adsorbing fluorine was subjected to desorption regeneration using an alkaline solution recovered as described below. The alkaline solution has 130% as hydroxyl ion.
mmot/L, 0.1 as calcium ion
mmol/L, and 1 mm as fluorine ion
It contained ot/l. The recovered alkaline liquid is transported to a superficial velocity of 21. As a result of passing 6.7 times the adsorbent volume through the same column as described above under r-1 conditions, the main component was sodium fluoride with an average fluorine ion concentration of 95 mmol/t and a pH of 6.8. When used as an eluent, the fluorine desorption rate is 100%.

Calcium hydroxide was added at a rate of 47.5 mmot/l (Oa''/F-) to recover an alkaline solution from the eluent.
=2 equivalent ratio) and stirred at 20°C for 30 minutes. As a result, the fluorine ions of sodium heptadide in the eluent precipitate as calcium fluoride, and the sodium is recovered as sodium hydroxide.

The composition of the recovered alkaline solution is 130 mmot as sodium hydroxide/3 as 1% calcium ion.
．． 7 mmot/L, 1 m as 7 ions
It is mot/l.

Next, the above alkaline solution was packed into a 10-1 column with a diameter of 10 mφ using the same adsorbent used for fluorine adsorption.
By passing the liquid at a superficial velocity of 30 hr-1, an alkaline solution with a calcium ion concentration of 0.1 mmol/l can be obtained in an amount 80 times the volume of the adsorbent, and can be used for desorption regeneration of the adsorbent after fluorine adsorption. It can be recovered as an alkaline solution. Note that the concentrations of sodium hydroxide and fluorine were not changed by this operation.

Adsorbent production method 4 Hydrate of yttrium fluoride: Dissolve yttrium chloride (reagent) in distilled water, add aqueous ammonia, and adjust the pH of the solution.
was prepared to 9. Yttrium 3 is added to the formed precipitate.
More than double the amount of hydrofluoric acid was added.

After aging overnight, the precipitate was thoroughly washed with distilled water, filtered, and dried at 60°C. The precipitate IP was suspended in 100 cc of an aqueous solution of 0, IN hydroxide, washed with water, filtered, and dried at 60°C.

Adsorbent manufacturing method 5 Polyacrylonitrile was dissolved in dimethylformamide at a concentration of 10% by weight, and the above-mentioned yttrium fluoride hydrate was added to the solution by 4 times the weight of the polymer and thoroughly stirred and dispersed. The mixture was shaped into granules using water as a coagulation bath.

[Brief explanation of drawings]

Figure 1 is a chart showing the pH dependence of the removal rate of fluorine ions, hexafluorosilicate ions, chloride ions, nitrate ions, sulfate ions, and calcium ions by hydrated cerium oxide used in the present invention, and Figure 2 is a graph showing the pH dependence of the removal rate of fluoride ions, hexafluorosilicate ions, chloride ions, nitrate ions, sulfate ions, and calcium ions by hydrated cerium oxide used in the present invention. /
Using an ethylene-vinyl alcohol copolymer adsorbent, 0. Figure 3a is an X-ray diffraction diagram of hydrated cerium oxide using OuKα rays as a representative of hydrated metal oxides. , Figure 3b shows its infrared absorption spectrum, and Figure 4a shows yttrium fluoride hydrate (7)0. Figure 4b shows an X-ray diffraction diagram using alpha rays, Figure 4b shows its infrared absorption spectrum, and Figure 5 is a flow sheet showing an example of the implementation of the present invention. 1... pH adjustment tank, 2... fixed bed column, 3...
Precipitated starch production 11144... Sedimented starch content [1w, 5.
...Fixed bed column. a... Fluorine-containing waste liquid, b... Processed waste liquid, C...
Alkaline regenerating solution, d... Eluent, e... Recovered alkaline solution Figure 1 H (%) Scale vW

Claims (2)

[Claims] (1) Fluorine and/or fluorine compounds in waste liquid,
When removing Ti, Zr, rare earth elements or actinides using metal hydrated oxides or metal hydrated fluorides, the pH of the waste liquid is adjusted to 7 or less and adsorption treatment is performed, followed by an alkaline bath solution with a pH of 10 or more. After regenerating the adsorbent to obtain a highly concentrated eluent of fluorine and/or fluorine compounds, adding a calcium salt to the eluent converts the fluorine and/or fluorine compounds in the eluent into calcium compounds. A method for treating fluorine-containing waste liquid, characterized by separating it by sedimentation. (2) A method for treating fluorine-containing waste liquid according to claim 1, wherein the eluent is recovered as an alkaline solution and recycled.