Method and apparatus for producing strongly basic anion exchange resin, and method for recycling strongly basic anion exchange resin

Abstract

To provide a method for producing a recycled strongly basic anion exchange resin applicable even to an application requiring high-purity water quality from a used non-recycled mixed bed ion exchange resin.SOLUTION: Provided is a method for producing a strongly basic anion exchange resin from a used non-recycled mixed bed ion exchange resin, including: a separation step of separating a strongly acidic cation exchange resin and a strongly basic anion exchange resin contained in the used non-recycled mixed bed ion exchange resin; and a recycling step of regenerating the separated strongly basic anion exchange resin using one or more recycling agents selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH), wherein the ratio of the strongly acidic cation exchange resin mixed in the separated strongly basic anion exchange resin (different resin mixing ratio) to the total volume of the ion exchange resin is 1 volume% or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and equipment for producing a strong base anion exchange resin from spent non-regenerated mixed bed ion exchange resin, and a method for recycling the strong base anion exchange resin. [Background technology]

[0002] Ion exchange resins used in pure water systems are disposed of as industrial waste by landfill or incineration after a certain period of use. However, studies are also being conducted to carbonize discarded ion exchange resins by dehydration or heating (Patent Document 1), or to crush them and reuse them as filter aids (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-012312 [Patent Document 2] Japanese Patent Application Publication No. 57-099336 Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Patent Documents 1 and 2, attempts have been made to reuse discarded ion exchange resins for purposes other than ion exchange resins. However, considering environmental and cost considerations, there is currently a need for the development of a method for reusing discarded ion exchange resins as ion exchange resins. One possible method for reusing ion exchange resins is to reuse the strongly basic anion exchange resins that make up used non-regenerated mixed-bed ion exchange resins as single-bed anion exchange resins. However, because it is difficult to completely separate the cation exchange resins and anion exchange resins contained in used non-regenerated mixed-bed ion exchange resins, the purity of the treated water is reduced due to the inclusion of counter ion exchange resins. This has led to the problem that such recycled ion exchange resins cannot be used in applications requiring high water purity.

[0005] The present invention aims to provide a method and equipment for producing a reusable strong basic anion exchange resin from a used non-regenerated mixed-bed ion exchange resin, which can be used in applications requiring high-purity water quality, and a method for reusing the strong basic anion exchange resin obtained by the above method. [Means for solving the problem]

[0006] The present invention provides a method for producing a strong base anion exchange resin from a used non-regenerated mixed bed ion exchange resin, comprising the steps of: a separation step of separating the strong acid cation exchange resin and the strong basic anion exchange resin contained in the used non-regenerated mixed bed ion exchange resin; a regeneration step of regenerating the separated strongly basic anion exchange resin using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH); and This is a method for producing a strongly basic anion exchange resin, characterized in that the proportion of strongly acidic cation exchange resin mixed in the strongly basic anion exchange resin after separation (foreign resin mixing rate) is 1 volume % or less relative to the total volume of the ion exchange resin.

[0007] The present invention also provides a method for reusing a strongly basic anion exchange resin, in which the strongly basic anion exchange resin produced by the above method is reused as an anion exchange resin in a single-bed anion exchange resin or a double-bed ion exchange resin.

[0008] The present invention further provides an apparatus for producing a strong base anion exchange resin from spent non-regenerated mixed bed ion exchange resin, comprising: a separation means for separating the strongly acidic cation exchange resin and the strongly basic anion exchange resin contained in the used non-regenerated mixed bed ion exchange resin; a regeneration means for regenerating the strong basic anion exchange resin after separation using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH); and This is a manufacturing facility for a strongly basic anion exchange resin, characterized in that the proportion of strongly acidic cation exchange resin mixed in the strongly basic anion exchange resin after the separation (foreign resin contamination rate) is 1 volume % or less relative to the total volume of the ion exchange resin. [Effects of the Invention]

[0009] According to the present invention, a recycled strongly basic anion exchange resin can be obtained from a used non-regenerated mixed-bed ion exchange resin, which can be used in applications requiring high-purity water quality. The recycled strongly basic anion exchange resin can be reused as a single-bed anion exchange resin or an anion exchange resin in a double-bed ion exchange resin. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating a part of the technical concept according to the present invention. [Figure 2] 1 is a schematic diagram showing an outline of a production facility for a strongly basic anion exchange resin according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] In the electronics industry, where high-purity pure water and ultrapure water are required, such as in the liquid crystal and semiconductor industries, non-regenerative ion exchange resin units are often installed at the end of primary water purification systems or in subsystem water purification systems to remove trace amounts of ions. While single-bed and dual-bed ion exchange resin units are sometimes used, mixed-bed ion exchange resin units are the most commonly used. In this specification, the ion exchange resins used in mixed-bed non-regenerative ion exchange resin units, i.e., the ion exchange resins used in mixed-bed non-regenerative ion exchange resin units, are referred to as "non-regenerative mixed-bed ion exchange resins." To reuse used non-regenerative mixed-bed ion exchange resins after use in a mixed-bed non-regenerative ion exchange resin unit, it is first necessary to separate the cation exchange resin and anion exchange resin contained in the used non-regenerative mixed-bed ion exchange resin. In this process of separating the cation exchange resin and the anion exchange resin, two patterns occur: (a) a pattern in which the cation exchange resin and the anion exchange resin cannot be completely separated, resulting in partial contamination of one resin with the other (a pattern of contamination with a different resin), and (b) a pattern in which the cation exchange resin and the anion exchange resin can be almost completely separated (a pattern of complete separation). The present inventors have intensively investigated methods for reusing used non-regenerated ion exchange resins that have been separated and regenerated in this manner. As a result, they have found that various methods are possible, such as reusing used non-regenerated ion exchange resins assuming contamination with a different resin (above (a)), or reusing used non-regenerated ion exchange resins assuming only slight contamination and almost complete separation (above (b)). Based on these findings, they have completed a series of inventions, including the present invention.

[0012] Among these inventions, this specification describes an invention relating to the reuse of used non-regenerated mixed-bed ion exchange resins, assuming the presence of other resins. Specifically, this specification describes an invention relating to the reuse of anion exchange resins contained in used non-regenerated mixed-bed ion exchange resins. The present invention will be described in detail below.

[0013] <Method for producing a strongly basic anion exchange resin> The method for producing a strongly basic anion exchange resin according to the present invention comprises at least the following steps: a separation step of separating a strongly acidic cation exchange resin and a strongly basic anion exchange resin contained in a used non-regenerated mixed-bed ion exchange resin; and a regeneration step of regenerating the separated strongly basic anion exchange resin using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH).

[0014] [Non-regenerative mixed-bed ion exchange resin] As described above, a non-regenerated mixed-bed ion exchange resin is a non-regenerated ion exchange resin used in a mixed-bed non-regenerated ion exchange resin device. Known mixed-bed ion exchange resins can be used as such non-regenerated mixed-bed ion exchange resins. Mixed-bed ion exchange resins are generally composed of a strongly acidic H-type cation exchange resin and a strongly basic OH-type anion exchange resin. The mixed-bed ion exchange resin is not particularly limited, but examples of commercially available products that can be used include ESP-2 (trade name, manufactured by Organo Corporation), AmberTec UP6040 H / OH (trade name, manufactured by DuPont de Nemours), DIAION SMT200L (trade name, manufactured by Mitsubishi Chemical Corporation), UltraClean UCW9966 (trade name, manufactured by Purolite), and LEWATIT UltraPure 1294MD (trade name, manufactured by Lanxess). The mixing ratio (volume ratio) of the strongly acidic cation exchange resin and the strongly basic anion exchange resin in the mixed-bed ion exchange resin is not limited, and the resins can be combined in any mixing ratio. The base material of the ion exchange resin may be either a transparent gel type with small pores, a macrolitercular type (MR type) with large macropores, or a macroporous type (also called a porous type or a hyperporous type).

[0015] [Separation process] The separation process separates the strongly acidic cation exchange resin and the strongly basic anion exchange resin contained in the used non-regenerated mixed-bed ion exchange resin after its use in purifying the treated water. Known methods can be appropriately selected and used to separate the strongly acidic cation exchange resin and the strongly basic anion exchange resin. Examples of separation methods include a method using a surface treatment agent, a method by converting the ion exchange resin's ionic form to a salt form, and a method using specific gravity. As mentioned above, the present invention is based on the premise that one of the cation exchange resins and the anion exchange resin contains some of the other resin. Therefore, if a large amount of the other resin is present in each ion exchange resin after separation, the other resin is reverse-regenerated with a regenerant and converted to a salt form ion in the regeneration process described below. As a result, reusing the regenerated ion exchange resin may affect the purity of the liquid to be purified. From the above, the proportion of strongly acidic cation exchange resin mixed into the separated strongly basic anion exchange resin obtained through the separation step (also referred to as the "foreign resin contamination rate") is 1% by volume or less, preferably 0.5% by volume or less, and more preferably 0.2% by volume or less, relative to 100% by volume of the total volume of ion exchange resin (the total volume of strongly acidic cation exchange resin and strongly basic anion exchange resin). If the foreign resin contamination rate of the strongly basic anion exchange resin is 1% by volume or less, a decrease in the purity of the treated water can be suppressed when the regenerated strongly basic anion exchange resin is used to purify the water to be treated. In the present invention, the foreign resin contamination rate is usually greater than 0% by volume.

[0016] [Regeneration process] In the regeneration step, the strongly basic anion exchange resin separated in the separation step is regenerated using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH). Since the present invention is a method for producing a strongly basic anion exchange resin derived from a used non-regenerated mixed-bed ion exchange resin, the subsequent treatment of the strongly acidic cation exchange resin separated in the separation step is not limited. The regeneration step can also be performed using a combination of two or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH. However, considering safety, treatment efficiency, and the like, it is preferable to perform the regeneration step using one of these regenerants. By performing the regeneration step, the strongly basic anion exchange resin derived from the used non-regenerated mixed-bed ion exchange resin (including any contaminated strongly acidic cation exchange resin) is regenerated into the OH form of the strongly basic anion exchange resin. The separated strongly basic anion exchange resin contains some strongly acidic cation exchange resin (foreign resin) that was not completely separated in the separation process, and the cations in the cation exchange resin are ion-exchanged with sodium ions, potassium ions, or tetramethylammonium ions in the regeneration process. These cations resulting from the foreign resin contamination affect the purity of the purified water. Therefore, in the present invention, the foreign resin contamination rate must be 1% by volume or less.

[0017] In the regeneration step, it is preferable to select the type of regenerant depending on the proportion of strongly acidic cation exchange resins mixed into the separated strongly basic anion exchange resin (foreign resin content). Specifically, if the foreign resin content in the separated strongly basic anion exchange resin is less than 0.2% by volume relative to the total volume of the ion exchange resin, it is preferable to regenerate the separated strongly basic anion exchange resin using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH. On the other hand, if the foreign resin content is 0.2% by volume or more and 1% by volume or less relative to the total volume of the ion exchange resin, it is preferable to regenerate the separated strongly basic anion exchange resin using one or more regenerants selected from sodium hydroxide and potassium hydroxide. By selecting a regenerant depending on the foreign resin content, deterioration of the water quality of the treated water obtained by purifying the water to be treated can be further suppressed.

[0018] The regeneration step can be carried out by a known method. Specifically, the separated strongly basic anion exchange resin is packed into a packed container such as an ion exchange resin tower, and a regenerant is passed through the container. The concentration of the regenerant is not particularly limited, but a regenerant having a concentration of 1% by mass to 10% by mass is typically used. The amount of regenerant used (regeneration level: RL) and the flow rate (SV) can be appropriately set; for example, the RL can be 1 to 5 eq / eq-R, and the SV can be 1 to 10. Here, the unit of RL, "eq / eq-R," refers to the chemical equivalent required per unit equivalent of resin. After passing the regenerant through the ion exchange resin, ultrapure water or pure water may be passed through to push out and wash the regenerant remaining in the ion exchange resin.

[0019] <Method for Reusing Strongly Basic Anion Exchange Resin> The recycled strong basic anion exchange resin obtained through the above-mentioned regeneration step can be reused as a single-bed anion exchange resin or an anion exchange resin in a double-bed ion exchange resin.

[0020] <Strongly basic anion exchange resin manufacturing facility> The production equipment for a strongly basic anion exchange resin according to the present invention is equipment for producing a strongly basic anion exchange resin from a used non-regenerated mixed-bed ion exchange resin, and comprises the following means: a separation means for separating the strongly acidic cation exchange resin and the strongly basic anion exchange resin contained in the used non-regenerated mixed-bed ion exchange resin; and a regeneration means for regenerating the separated strongly basic anion exchange resin with one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH. Each means will be described below with reference to FIG. 2.

[0021] [Separation means] The separation means is a means for carrying out the separation step. The separation means is not limited to any known means capable of separating the strongly acidic cation exchange resin and the strongly basic anion exchange resin contained in used non-regenerative mixed-bed ion exchange resin after its use in purifying the water to be treated. Examples of separation means include a method using a surface treatment agent, a method by converting the ion exchange resin's ionic form to a salt form, and a method using specific gravity. Specifically, the separation means includes a packed container 1, such as an ion exchange resin tower, filled with the used non-regenerative mixed-bed ion exchange resin, and a means for passing chemicals, etc. required for separation through a chemical line L1. For example, as shown in FIG. 2, the strongly acidic cation exchange resin A and the strongly basic anion exchange resin B are separated by passing a chemical, etc. through the chemical line L1 to the used non-regenerative mixed-bed ion exchange resin (strongly basic anion exchange resin A and strong acidic cation exchange resin B) packed in the ion exchange resin tower 1. The proportion of strongly acidic cation exchange resin mixed in the separated strongly basic anion exchange resin (foreign resin contamination rate) obtained through the separation means is 1% by volume or less, preferably 0.5% by volume or less, and more preferably 0.2% by volume or less, based on 100% by volume of the total volume of ion exchange resin (total volume of strongly acidic cation exchange resin and strongly basic anion exchange resin). The separated strongly basic anion exchange resin A is extracted from the bottom of ion exchange resin tower 1 and transferred through resin line L2 to ion exchange resin tower 2, which serves as a regeneration means. The chemicals used for resin separation can be discharged from the bottom of ion exchange resin tower 1 through waste liquid line L3 to the outside of the system.

[0022] [Reproduction means] The regeneration means is a means for carrying out the regeneration step described above, and is a means for regenerating the strongly basic anion exchange resin separated by the separation means using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH. Known regeneration means can be used. Specifically, the regeneration means includes a packed container 2, such as an ion exchange resin tower, packed with the separated strongly basic anion exchange resin A, and a means for passing the regenerant through a regenerant line L4. For example, as shown in Figure 2, the strongly basic anion exchange resin A packed in the ion exchange resin tower 2 through the resin line L2 is regenerated by passing the regenerant through the regenerant line L4. After passing the regenerant, ultrapure water or pure water may be passed through the pure water line L5 to push out and wash out the regenerant remaining in the resin. The regenerant and pure water used to regenerate the resin can be discharged from the bottom of the ion exchange resin tower 2 through a waste liquid line L6.

[0023] In addition, the above-mentioned explanations regarding the method for producing a strongly basic anion exchange resin according to the present invention can be applied appropriately to the production equipment for a strongly basic anion exchange resin according to the present invention. [Example]

[0024] [Examples 1 to 3 and Reference Example 1] (1.Resin used) The following ion exchange resins were used as the H-type strongly acidic cation exchange resin (hereinafter abbreviated as "cation") and the OH-type strongly basic anion exchange resin (hereinafter abbreviated as "anion"), respectively. Cation: AMBERLITE HPR1500 H (trade name, manufactured by DuPont) Anion: AMBERLITE HPR4200 OH (trade name, manufactured by DuPont)

[0025] (2. Combination) In each example, the resins were weighed out in the amounts shown in Table 1 and mixed appropriately. The resin configuration in which anions and cations are mixed is intended to simulate an anion exchange resin containing a mixed resin (cation exchange resin), which is obtained by separating the cation exchange resin and the anion exchange resin after use in a mixed bed state.

[0026] [Table 1]

[0027] (3. Regeneration process) The obtained resin was packed into an ion-exchange resin tower, and then regeneration treatment was carried out under the following two conditions. <Regeneration condition 1: Sodium hydroxide treatment> 882 g of 4 mass% sodium hydroxide aqueous solution (RL=3 eq / eq-R) was passed through the resin packed in the ion exchange resin tower at SV=4, and then the resin was extruded and washed using ultrapure water at SV=10 and BV=10. <Regeneration condition 2: TMAH treatment> 887 g of a 9.25 mass % TMAH aqueous solution (RL=3 eq / eq-R) was passed through the resin packed in the ion exchange resin tower at SV=4, and then the resin was extruded and washed using ultrapure water at SV=10 and BV=10.

[0028] (4. Evaluation) Ultrapure water was passed through the regenerated resin at SV=50, and the resistivity of the treated water obtained from the outlet of the ion exchange resin tower was measured after each time interval using a resistivity meter (Foxboro 871CC, manufactured by T&C Technical Co., Ltd.). The results are shown in Table 2.

[0029] [Table 2]

[0030] As shown in Table 2, when TMAH was used as the regenerant, the final water quality was found to be inferior compared to when NaOH was used as the regenerant when the foreign resin contamination rate was 0.2% by volume or more. These results demonstrate that when the foreign resin contamination rate is less than 0.2% by volume relative to the total volume of the ion exchange resin, it is preferable to regenerate the strong basic anion exchange resin using one or more regenerants selected from sodium hydroxide, potassium hydroxide, and TMAH. However, when the foreign resin contamination rate is 0.2% by volume or more and 1% by volume or less relative to the total volume of the ion exchange resin, it is preferable to regenerate the strong basic anion exchange resin using sodium hydroxide or potassium hydroxide. [Explanation of symbols]

[0031] 1. Separation means (ion exchange resin tower) 2. Regeneration method (ion exchange resin tower) A Strongly basic anion exchange resin B Strongly acidic cation exchange resin L1 Chemical solution line L2 Resin Line L3 Waste liquid line L4 Regenerant Line L5 Pure water line L6 Waste liquid line

Claims

1. 1. A method for producing a strong base anion exchange resin from spent non-regenerated mixed bed ion exchange resin, comprising: a separation step of separating the strong acid cation exchange resin and the strong basic anion exchange resin contained in the used non-regenerated mixed bed ion exchange resin; a regeneration step of regenerating the separated strongly basic anion exchange resin using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH); and A method for producing a strongly basic anion exchange resin, characterized in that the ratio of strongly acidic cation exchange resin mixed in the strongly basic anion exchange resin after separation (foreign resin mixing rate) is 1 volume % or less based on the total volume of the ion exchange resin.

2. In the regeneration step, If the rate of contamination with the other resin is less than 0.2% by volume based on the total volume of the ion exchange resin, the strong basic anion exchange resin after separation is regenerated using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH; When the rate of contamination with the foreign resin is 0.2% by volume or more and 1% by volume or less based on the total volume of the ion exchange resin, the strong basic anion exchange resin after separation is regenerated using one or more regenerants selected from sodium hydroxide and potassium hydroxide. A method for producing the strongly basic anion exchange resin according to claim 1.

3. 3. A method for reusing a strongly basic anion exchange resin, comprising reusing the strongly basic anion exchange resin produced by the method of claim 1 or 2 as an anion exchange resin in a single-bed anion exchange resin or a double-bed ion exchange resin.

4. 1. An apparatus for producing a strong base anion exchange resin from spent non-regenerated mixed bed ion exchange resin, comprising: a separation means for separating the strongly acidic cation exchange resin and the strongly basic anion exchange resin contained in the used non-regenerated mixed bed ion exchange resin; a regeneration means for regenerating the strong basic anion exchange resin after separation using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide (TMAH); and A production facility for a strongly basic anion exchange resin, characterized in that the ratio of strongly acidic cation exchange resin mixed in the strongly basic anion exchange resin after separation (foreign resin mixing rate) is 1 volume % or less based on the total volume of the ion exchange resin.

5. In the regenerating means, If the rate of contamination with the other resin is less than 0.2% by volume based on the total volume of the ion exchange resin, the strong basic anion exchange resin after separation is regenerated using one or more regenerants selected from the group consisting of sodium hydroxide, potassium hydroxide, and TMAH; When the rate of contamination with the foreign resin is 0.2% by volume or more and 1% by volume or less based on the total volume of the ion exchange resin, the strong basic anion exchange resin after separation is regenerated using one or more regenerants selected from sodium hydroxide and potassium hydroxide. A facility for producing the strongly basic anion exchange resin according to claim 4.

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