JP2013132581A - Method for conditioning anion exchange resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for conditioning an anion exchange resin, which enables reduction of the amount of hydrofluoric acid chemical solution to be used.SOLUTION: There is disclosed a method for conditioning an anion exchange resin comprising bringing an OH-form anion exchange resin into contact with a liquid containing hydrofluoric acid to convert it into an F-form anion exchange resin, which method is characterized in that the liquid containing hydrofluoric acid is at least one member selected from among a liquid waste containing hydrofluoric acid, a refined waste liquid prepared by treating a liquid waste containing hydrofluoric acid with an ion exchange resin, and a liquid produced when a tank for a liquid waste containing hydrofluoric acid is rinsed with water or a diluted liquid thereof.

Description

  The present invention relates to a method for conditioning an anion exchange resin for converting (adjusting) an OH type anion exchange resin into an F type anion exchange resin.

  Conventionally, waste hydrofluoric acid used for substrate cleaning in the manufacturing process of solar cells, semiconductors, and the like has been disposed of as industrial waste, and there are problems of increasing environmental load and chemical usage due to industrial waste. For the purpose of recycling waste hydrofluoric acid, a technology for purifying hydrofluoric acid using an anion exchange resin is known. For example, Patent Document 1 describes a method of recovering hydrofluoric acid by removing nitric acid by bringing a semiconductor cleaning wastewater containing hydrofluoric acid and nitric acid into contact with an anion exchange resin.

  As the anion exchange resin used here, it is desirable to use a resin that has been previously converted from OH form (hydroxide ion form) to F form (fluoride ion form) so that hydrofluoric acid is not diluted.

  An anion exchange resin to be purified needs to be periodically regenerated with an alkali to be converted into OH form to recover its performance. When used for purification of hydrofluoric acid, this OH-type anion exchange resin is converted to F-type.

  A separate hydrofluoric acid is required to adjust the anion exchange resin to the F form during initial cleaning and regeneration. Conventionally, a high-purity hydrofluoric acid reagent is used as the hydrofluoric acid, but the cost is high and the environmental load and the amount of chemical solution used are reduced.

JP 2003-81613 A

  An object of this invention is to provide the conditioning method of the anion exchange resin which makes it possible to reduce the usage-amount of a hydrofluoric acid chemical | medical solution.

  The method for conditioning an anion exchange resin according to the present invention is a method for conditioning an anion exchange resin in which an OH type anion exchange resin is brought into contact with a hydrofluoric acid-containing liquid to convert it to an F type anion exchange resin. It is characterized by being at least one kind of diluted waste liquid containing hydrofluoric acid containing waste liquid purified by ion exchange resin, and rinsing water of a hydrofluoric acid containing waste liquid tank, or a diluted liquid thereof.

  The concentration of hydrofluoric acid in the hydrofluoric acid-containing liquid brought into contact with the anion exchange resin is preferably 0.1 to 15 wt%.

  In the present invention, in a method of performing conditioning by bringing a hydrofluoric acid-containing liquid into contact with an anion exchange resin, a hydrofluoric acid-containing waste liquid, a purified waste liquid obtained by purifying the hydrofluoric acid-containing waste liquid with an ion exchange resin, and hydrofluoric acid Since at least one type of rinse water in the contained waste liquid tank or a diluted solution thereof is used, the amount of chemical used for conditioning the anion exchange resin can be reduced. In the method of the present invention, a low-concentration hydrofluoric acid waste liquid discharged from a manufacturing process in a factory or a hydrofluoric acid waste liquid adjusted to a low concentration can be used for F-type conversion of an anion exchange resin. No high purity hydrofluoric acid reagent is required. Further, it is possible to reduce the load of waste liquid treatment of hydrofluoric acid waste liquid discharged from the manufacturing process.

It is a block diagram demonstrated by embodiment. It is a graph which shows an experimental result. It is a graph which shows an experimental result.

  Hereinafter, the present invention will be described in more detail.

  In the present invention, an anion exchange resin is brought into contact with a hydrofluoric acid-containing liquid to convert an OH type anion exchange resin into an F type anion exchange resin. In addition, as the hydrofluoric acid-containing liquid, at least one kind of fluoric acid-containing waste liquid, purified waste liquid obtained by purifying the hydrofluoric acid-containing waste liquid with an ion exchange resin, and rinse water of a hydrofluoric acid-containing waste liquid tank or a diluted liquid thereof are used.

  As the anion exchange resin, an anion exchange resin generally used in water treatment can be used. The anion exchange resin may be a strong base anion exchange resin or a weak base anion exchange resin. However, when the hydrofluoric acid-containing liquid is an acidic liquid containing other acid components such as nitric acid, the weak base anion exchange resin is used. Is preferably used. Preferred anion exchange resins include polystyrene-type anion exchange resins crosslinked with divinylbenzene and having an alkyl or alkanolamine type anion exchange group. In the case of strongly basic anion exchange resins, quaternary ammonium type resins are used. In the case of a weakly basic anion exchange resin having an anion exchange group, those having a primary to tertiary amine type anion exchange group may be mentioned. As the exchange group, OH form (hydroxide ion) or F form (fluoride ion) can be used.

  Examples of the hydrofluoric acid-containing waste liquid include, but are not limited to, wastewater from a semiconductor manufacturing process, a glass surface treatment process, and the like. The concentration of hydrofluoric acid in the hydrofluoric acid-containing waste liquid is usually 0.1 to 50 wt%, particularly 0.5 to 15 wt%.

  This hydrofluoric acid-containing waste liquid contains acid components such as nitric acid, hydrochloric acid and sulfuric acid, metal ions such as Fe, Cu, Zn, Na, K, Ca, Al, Mo, Ti and B, or borofluoride and phosphate ions. May be included.

  This hydrofluoric acid-containing waste liquid may be supplied as it is to the conditioning step of the anion exchange resin, or may be supplied to the conditioning step after performing a purification treatment with a cation exchange resin or the like.

  The hydrofluoric acid concentration of the hydrofluoric acid-containing liquid that is brought into contact with the anion exchange resin during conditioning is preferably 2 wt% or less, particularly about 0.1 to 2.0 wt%. Accordingly, when the hydrofluoric acid concentration of the hydrofluoric acid-containing waste liquid, the purified liquid thereof, or the hydrofluoric acid-containing waste liquid tank rinsing water is higher than this range, it is preferable to dilute with the diluting water to be within this range.

  In the conditioning step, the hydrofluoric acid-containing liquid is brought into contact with the OH-type anion exchange resin to adsorb fluoride ions on the anion exchange resin.

The contact between the hydrofluoric acid-containing liquid and the anion exchange resin may be simple immersion, but in general, the anion exchange resin is packed in a column to form an anion exchange resin layer, and the hydrofluoric acid-containing liquid is passed through the column. A liquid that adsorbs fluoride ions is preferable. The flow rate of the hydrofluoric acid-containing liquid through this column is preferably SV100h ⁻¹ or less, particularly preferably SV1 to 10h ⁻¹ .

  In this state, it is preferable that the liquid is continuously passed and adsorption (conditioning) is performed until hydrofluoric acid leaks. If the liquid flow is continued in this manner, the fluoride ion is finally adsorbed on the entire anion exchange resin and converted into an F-type anion exchange resin. This F-type anion exchange resin can be suitably used, for example, for the purpose of recovering hydrofluoric acid by adsorbing and removing hydrofluoric acid ions from a waste liquid containing hydrofluoric acid and hydrofluoric acid.

  FIG. 1 is a block diagram showing an example of an apparatus suitable for carrying out the method of the present invention.

  In FIG. 1, a tank 20 for storing a hydrofluoric acid-containing factory waste liquid, a purified waste liquid storage tank 21 obtained by purifying the hydrofluoric acid-containing factory waste liquid by a purification means (not shown), and rinse water when the tank 20 or 21 is rinse-washed. A tank 22 for storage is installed, and piping and valves are provided so that the hydrofluoric acid-containing liquid is supplied from any of the tanks 20 to 22 to the anion exchange resin-filled column 26 via the circulation tank 25. In addition, the waste liquid can be received in the mixing tank 24, diluted with the dilution water from the tank 23, and supplied to the column 26.

  A circulation tank 25 is installed in the front stage of the column 26. By opening the valves 13 and 24 and operating the pump 19, the hydrofluoric acid-containing liquid in the circulation tank 25 can be circulated through the column 26.

  When supplying the factory waste liquid in the tank 20 to the circulation tank 25, the valves 1, 6 and 12 are opened, and when supplying the purified waste liquid in the tank 21 to the circulation tank 25, the valves 3, 6, 12 are opened. When the rinsing water in the tank 22 is supplied to the circulation tank 25, the valves 7 and 12 are opened. When the liquid in the tank 20 is diluted and then supplied to the circulation tank 25, the valves 1, 6, 9, 10, and 11 are opened, and the liquid in the tank 20 is mixed with the water from the tank 23 in the mixing tank 24. Then, it is diluted and supplied to the circulation tank 25. When the liquid in the tank 21 is diluted and then supplied to the circulation tank 25, the valves 3, 6, 9, 10 and 11 are opened, and when the liquid in the tank 22 is diluted and then supplied to the circulation tank 25, Valves 7, 9, 10, and 11 are opened.

  When circulating the liquid in the circulation tank 25 through the column 26, the valves 13 and 14 are opened, the valve 15 is closed, and the pump 19 is operated.

  The hydrofluoric acid concentration of the hydrofluoric acid-containing liquid that passes through the column 26 is preferably 15 wt% or less, for example, 0.1 to 15 wt%, particularly about 0.2 to 2 wt%. The water flow SV to the column 26 is preferably 10 or less, particularly about 3 to 7, and the BV is preferably about 1 to 1000, particularly about 3 to 900.

[Examples 1 to 4]
The column was packed with 15 mL of OH-type anion exchange resin (MP62 manufactured by LANXESS) and used as a simulated factory waste solution as an industrial hydrofluoric acid aqueous solution (hydrofluoric acid concentration 0.25 wt% (Example 1), 0.5 wt% (Example 2). ), 1.0 wt% (Example 3), or 2.0 wt% (Example 4)) was passed through BV = 200 by SV8. Thereafter, the anion exchange resin was regenerated with an HClO ₄ solution, and the fluoride ion concentration in the regenerated solution was analyzed to measure the F-formation rate. The results are shown in Table 1.

[Comparative Examples 1-4]
Except for using an aqueous solution of a high-purity hydrofluoric acid reagent as the hydrofluoric acid aqueous solution, water was passed in the same manner as in Examples 1 to 4 to form an anion exchange resin, and the F-formation rate was measured. The results are shown in Table 1.

  As shown in Table 1, the F-formation rate by conditioning was substantially the same in Examples 1 to 4 using industrial hydrofluoric acid and Comparative Examples 1 to 4 using high-purity reagent hydrofluoric acid. It was.

[Confirmation of anion exchange performance]
The column was filled with the F-type anion exchange resin conditioned in Example 2 and Comparative Example 2, and the silicic acid solution was passed under the following conditions, and the change over time in the silicic acid concentration in the column effluent was measured. The results are shown in FIG.
<Water flow conditions>
Filled resin amount: 15 mL
SV5
HF 5%
Silicic acid load: 138 mg / L
As shown in FIG. 2, the silicic acid removal ability of the F-type anion exchange resin conditioned in Example 2 and Comparative Example 2 was equivalent.

[Confirmation of resin adsorption performance]
An adsorption equilibrium test was performed on the anion exchange resin conditioned in Example 3 and Comparative Example 3. That is, 15 mL of F-type anion exchange resin conditioned in Example 3 and Comparative Example 3 was placed in an adsorption equilibrium test container (500 mL), and an aqueous hydrofluoric acid hydrofluoric acid solution having an HF concentration of 5 wt% as shown in FIG. 300 mL was poured into the container, sealed, and then shaken at room temperature for 15 hours. After 15 hours, the concentration of silicic acid in the solution was measured, and the amount of silicic acid adsorbed was measured. The results are shown in FIG.

  As shown in FIG. 3, the equilibrium adsorption amount of silicic acid of the F-type anion exchange resin conditioned in Example 3 and Comparative Example 3 was the same.

  From the above experiment, according to the present invention, the F-form anion exchange resin obtained by conditioning the OH-form anion exchange resin to the F-form anion exchange resin using the hydrofluoric acid waste liquid is the F-form anion exchange conditioned using the high-purity hydrofluoric acid reagent. It was found to have an ion exchange capacity equivalent to that of the resin.

1-15 Valve 25 Circulation tank 26 Anion exchange resin packed column

Claims (2)

In the conditioning method of an anion exchange resin in which an OH type anion exchange resin is contacted with a hydrofluoric acid-containing liquid and converted to an F type anion exchange resin,
The hydrofluoric acid-containing liquid is at least one of a hydrofluoric acid-containing waste liquid, a purified waste liquid obtained by purifying the hydrofluoric acid-containing waste liquid with an ion exchange resin, and a rinsing water of a hydrofluoric acid-containing waste liquid tank or a diluted liquid thereof. An anion exchange resin conditioning method.   The method for conditioning an anion exchange resin according to claim 1, wherein the concentration of hydrofluoric acid in the hydrofluoric acid-containing liquid brought into contact with the anion exchange resin is 0.1 to 2 wt%.

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