JP2023059066A - Purification method for acid solution - Google Patents

Purification method for acid solution Download PDF

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JP2023059066A
JP2023059066A JP2021168956A JP2021168956A JP2023059066A JP 2023059066 A JP2023059066 A JP 2023059066A JP 2021168956 A JP2021168956 A JP 2021168956A JP 2021168956 A JP2021168956 A JP 2021168956A JP 2023059066 A JP2023059066 A JP 2023059066A
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exchange resin
ion
ion exchange
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智子 ▲高▼田
Tomoko Takada
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Organo Corp
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Japan Organo Co Ltd
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Priority to PCT/JP2022/030571 priority patent/WO2023062925A1/en
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/04—Processes using organic exchangers
    • B01J39/05—Processes using organic exchangers in the strongly acidic form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/04—Processes using organic exchangers
    • B01J39/07—Processes using organic exchangers in the weakly acidic form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J41/00—Anion exchange; Use of material as anion exchangers; Treatment of material for improving the anion exchange properties
    • B01J41/04—Processes using organic exchangers
    • B01J41/05—Processes using organic exchangers in the strongly basic form
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J41/00—Anion exchange; Use of material as anion exchangers; Treatment of material for improving the anion exchange properties
    • B01J41/04—Processes using organic exchangers
    • B01J41/07—Processes using organic exchangers in the weakly basic form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J45/00—Ion-exchange in which a complex or a chelate is formed; Use of material as complex or chelate forming ion-exchangers; Treatment of material for improving the complex or chelate forming ion-exchange properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J47/00—Ion-exchange processes in general; Apparatus therefor
    • B01J47/016—Modification or after-treatment of ion-exchangers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
    • B01J49/10—Regeneration or reactivation of ion-exchangers; Apparatus therefor of moving beds
    • B01J49/16—Regeneration or reactivation of ion-exchangers; Apparatus therefor of moving beds containing cationic and anionic exchangers in separate beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
    • B01J49/10—Regeneration or reactivation of ion-exchangers; Apparatus therefor of moving beds
    • B01J49/18—Regeneration or reactivation of ion-exchangers; Apparatus therefor of moving beds of mixed beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
    • B01J49/50—Regeneration or reactivation of ion-exchangers; Apparatus therefor characterised by the regeneration reagents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J49/00—Regeneration or reactivation of ion-exchangers; Apparatus therefor
    • B01J49/60—Cleaning or rinsing ion-exchange beds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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Abstract

To provide a purification method capable of providing acid solution with further reduced impurity concentration.SOLUTION: A purified ion exchange resin is obtained by contacting an ion exchange resin to be purified with a mineral acid solution with a metal impurity content of 1 mg/L or less and a concentration of 5 wt.% or higher. The purification of acid solution using a purified ion exchange resin in which the amount of total metal impurities eluted when the purified ion exchange resin is passed through hydrochloric acid at a concentration of 3 wt.% by volume 25 times or less is 5 μg/mL-R or less. Preferably, the content of sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) in the mineral acid solution is less than 200 μg/L each, and the ion exchange resin includes a styrene-type strong acid ion exchange resin with a particle size of 100 μm or more and 400 μm or less.SELECTED DRAWING: None

Description

本発明は、酸性溶液の精製方法に関し、詳細には、イオン交換樹脂を用いた酸性溶液中の金属不純物を低減する精製方法に関する。 TECHNICAL FIELD The present invention relates to a method for purifying an acidic solution, and more particularly to a method for reducing metal impurities in an acidic solution using an ion exchange resin.

半導体製造工程において、様々な工程でそれぞれ適した薬液が使用されるが、一様に低い不純物濃度が要求されている。
無機酸、有機酸のような酸性溶液も、半導体製造工程で使用される薬液であり、低い不純物濃度が要求される。
酸性溶液の精製方法としては、近年、設備費用負担が小さく、省エネルギーで、不純物を高度に精製除去し得るイオン交換樹脂やイオン交換フィルタ等を用いたイオン交換法による精製方法が報告されている。 2. Description of the Related Art In semiconductor manufacturing processes, suitable chemical solutions are used in various processes, but uniformly low impurity concentrations are required.
Acidic solutions such as inorganic acids and organic acids are also chemical solutions used in semiconductor manufacturing processes, and low impurity concentrations are required.
As a method for purifying an acidic solution, in recent years, a purification method by an ion exchange method using an ion exchange resin, an ion exchange filter, etc., which is capable of purifying and removing impurities to a high degree with a low equipment cost and energy saving, has been reported.

例えば、アニオン交換樹脂、カチオン交換樹脂を用いた酸溶液の精製に関して様々な先行技術が存在する。キレート樹脂も酸性溶液の精製、特に有価物回収に使用されるのは一般的であり、多くの文献が存在する。
酸性溶液の精製では、無機酸、有機酸、あるいは有機溶媒と有機酸の混合溶液からの金属除去についての文献が存在する。
無機酸の精製では、特に塩酸中では様々な金属が塩化物錯体として存在し、アニオン樹脂で除去できることが知られている（例えば特許文献１、２及び非特許文献１参照）。例えば、特許文献１では金属錯体を含む粗塩酸の精製に微粒子フィルタ、陰イオン交換樹脂及び陽イオン交換樹脂を用いている。またリン酸中の金属除去方法についての報告も存在する（例えば特許文献３参照）。
有機酸の精製についても、アニオン樹脂を使って金属不純物が除去できることが過去の文献で報告されており、精製対象となる有機酸形で使用する場合や（例えば、特許文献４参照）、Ｃｌ形で使用する場合（例えば、特許文献５）などが報告されている。
特許文献６では、有機酸と有機溶媒の混合物から、金属不純物を、非金属形の樹脂（Ｈ形、ＯＨ形）を用いて低減している。
また有機酸の製造時において、イオン交換樹脂による処理を行う場合がある。例えば特許文献７は、微生物による発酵法で得られる粗有機酸塩溶液を、イオン交換膜による電気透析、キレート樹脂処理、イオン交換膜による水分解電気透析で処理することにより、有機酸を製造する方法について報告されている。 For example, there are various prior arts relating to the purification of acid solutions using anion exchange resins, cation exchange resins. Chelate resins are also generally used for the purification of acidic solutions, especially for the recovery of valuables, and there are many documents.
In the purification of acidic solutions, the literature exists on the removal of metals from inorganic acids, organic acids, or mixed solutions of organic solvents and organic acids.
In the purification of inorganic acids, it is known that various metals exist as chloride complexes, particularly in hydrochloric acid, and can be removed with an anion resin (see Patent Documents 1 and 2 and Non-Patent Document 1, for example). For example, Patent Document 1 uses a particulate filter, an anion exchange resin and a cation exchange resin for purification of crude hydrochloric acid containing a metal complex. There is also a report on a method for removing metals in phosphoric acid (see Patent Document 3, for example).
Regarding the purification of organic acids, it has been reported in past literature that metal impurities can be removed using anion resins. (For example, Patent Document 5) and the like have been reported.
In Patent Document 6, metal impurities are reduced from a mixture of an organic acid and an organic solvent using a non-metallic resin (H type, OH type).
Further, in the production of organic acids, treatment with an ion-exchange resin may be performed. For example, in Patent Document 7, an organic acid is produced by treating a crude organic acid salt solution obtained by a fermentation method using microorganisms by electrodialysis with an ion-exchange membrane, chelate resin treatment, and water-splitting electrodialysis with an ion-exchange membrane. methods have been reported.

特開２０２０－１９５５号公報Japanese Patent Application Laid-Open No. 2020-1955 特許４５２３３２１号公報Japanese Patent No. 4523321 特開２０１６－２２４７７号公報JP 2016-22477 A 特許４５３４５９１号公報Japanese Patent No. 4534591 特開昭６１－２７４７８９号公報JP-A-61-274789 特許６７７２１３２号公報Japanese Patent No. 6772132 特許３９６５２２０号公報Japanese Patent No. 3965220

ダイヤイオン：DIAION イオン交換樹脂・合成吸着剤マニュアル［II］，（株）三菱化成工業，P95-97，第87-89図DIAION: DIAION Ion Exchange Resin/Synthetic Adsorbent Manual [II], Mitsubishi Chemical Industries, Ltd., P95-97, Figures 87-89

電子機器の小型化による高集積化に伴い、半導体製造工程で使用される酸性溶液の不純物もさらに低減することが望まれている。
したがって、本発明の目的は、不純物濃度が一層低減された酸性溶液を提供し得る精製方法を提供することにある。 With the miniaturization of electronic equipment and the high integration thereof, it is desired to further reduce the impurities in the acidic solution used in the semiconductor manufacturing process.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a purification method capable of providing an acidic solution with a further reduced concentration of impurities.

イオン交換樹脂による精製対象である酸性溶液は、イオン交換樹脂から金属不純物を溶出させやすいという、中性溶液中では起こらない酸溶液中特有の課題が存在する。
そこで、本発明者は、酸性溶液精製時におけるイオン交換樹脂からの金属不純物の溶出を低減する方法を見出し、金属不純物の溶出が低減されたイオン交換樹脂を用いることにより、上記目的を達成した。
具体的には、上記目的は、下記［１］ないし［８］により達成される。
［１］ イオン交換樹脂を使用する酸性溶液の精製方法であって、
前記イオン交換樹脂は、精製対象のイオン交換樹脂に、金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することにより得られる精製イオン交換樹脂であって、前記精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量は、５μｇ／ｍＬ―Ｒ以下であることを特徴とする酸性溶液の精製方法。
［２］ 前記鉱酸溶液におけるナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、および鉄（Ｆｅ）の含有量は、それぞれ２００μｇ／Ｌ以下であることを特徴とする前記［１］に記載の酸溶液の精製方法。
［３］ 前記イオン交換樹脂は、スチレン型強酸性イオン交換樹脂を含むことを特徴とする前記［１］又は［２］に記載の酸溶液の精製方法。
［４］ 前記スチレン型強酸性イオン交換樹脂の粒径が、１００μｍ以上４００μｍ以下であることを特徴とする前記［１］～［３］のいずれか１つに記載の酸溶液の精製方法。
［５］ 前記［１］～［４］のいずれか１つに記載の精製方法を用いて酸溶液を精製した後のイオン交換樹脂を、鉱酸溶液に接触させた後、洗浄水のＴＯＣが３０ｐｐｂ以下に達するまで水洗浄を実施することを特徴とする酸溶液精製用イオン交換樹脂の再生方法。
［６］ 前記イオン交換樹脂として、前記［５］に記載の再生方法により再生した再生イオン交換樹脂を用いることを特徴とする、前記［１］～［４］のいずれか１つに記載の酸性溶液の精製方法。
［７］ 対象のイオン交換樹脂に、金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することにより精製カチオン交換樹脂を得るイオン交換樹脂精製手段であって、前記精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量は、５μｇ／ｍＬ―Ｒ以下である、イオン交換樹脂精製手段と、
前記精製イオン交換樹脂を用いて酸性溶液を精製する、酸性溶液精製手段と、
を備えることを特徴とする酸性溶液精製装置。
［８］ 酸性溶液の精製後のイオン交換樹脂の再生機能を有する、前記［７］に記載の酸溶液精製装置。 Acidic solutions to be purified by ion-exchange resins have a problem specific to acid solutions that does not occur in neutral solutions, namely that metal impurities are likely to be eluted from the ion-exchange resins.
Accordingly, the present inventors have found a method for reducing the elution of metal impurities from an ion exchange resin during purification of an acidic solution, and have achieved the above object by using an ion exchange resin in which the elution of metal impurities is reduced.
Specifically, the above objects are achieved by the following [1] to [8].
[1] A method for purifying an acidic solution using an ion exchange resin, comprising:
The ion-exchange resin is a purified ion-exchange resin obtained by contacting an ion-exchange resin to be purified with a mineral acid solution having a metal impurity amount of 1 mg/L or less and a concentration of 5% by weight or more for purification. The total amount of eluted metal impurities eluted when hydrochloric acid having a concentration of 3% by weight is passed through the purified ion exchange resin at a volume ratio of 25 times is 5 μg / mL-R or less. A method for purifying a solution.
[2] The above [1], wherein the contents of sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) in the mineral acid solution are each 200 µg/L or less. A method for purifying the acid solution described.
[3] The method for purifying an acid solution according to [1] or [2], wherein the ion exchange resin contains a styrene-type strongly acidic ion exchange resin.
[4] The method for purifying an acid solution according to any one of [1] to [3], wherein the styrene-type strongly acidic ion exchange resin has a particle size of 100 μm or more and 400 μm or less.
[5] After contacting the ion exchange resin after purifying the acid solution using the purification method according to any one of [1] to [4] with a mineral acid solution, the TOC of the wash water is A method for regenerating an ion exchange resin for purifying an acid solution, comprising washing with water until the concentration reaches 30 ppb or less.
[6] The acid according to any one of [1] to [4], wherein the ion exchange resin is a regenerated ion exchange resin regenerated by the regeneration method according to [5]. A method for purifying a solution.
[7] An ion-exchange resin purification means for obtaining a purified cation-exchange resin by contacting a target ion-exchange resin with a mineral acid solution having a metal impurity amount of 1 mg/L or less and a concentration of 5% by weight or more for purification. The amount of all metal impurities eluted when hydrochloric acid having a concentration of 3% by weight is passed through the purification ion exchange resin at a volume ratio of 25 times is 5 μg / mL-R or less, ion exchange resin purification. means and
an acidic solution purifying means for purifying an acidic solution using the purified ion exchange resin;
An acidic solution purification device comprising:
[8] The acid solution purifier according to [7] above, which has a function of regenerating an ion exchange resin after purification of the acid solution.

本発明によれば、不純物濃度が一層低減された酸性溶液を提供し得る精製方法を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the refinement|purification method which can provide the acidic solution with which impurity density|concentration was further reduced can be provided.

図１は、再生前と再生後のクエン酸精製試験におけるクエン酸溶液中の金属不純物の除去率の差を示すグラフである。FIG. 1 is a graph showing the difference in removal rate of metal impurities from a citric acid solution in a citric acid purification test before and after regeneration.

以下、本発明の実施形態について以下詳細に説明する。本実施形態は本発明を実施する一例であって、本発明は本実施形態に限定されない。 Hereinafter, embodiments of the present invention will be described in detail. This embodiment is an example of implementing the present invention, and the present invention is not limited to this embodiment.

＜酸性溶液の精製方法＞
本発明の酸性溶液の精製方法では、予め、特定の鉱酸溶液を接触させて精製したイオン交換樹脂を使用して酸性溶液を精製する。
精製の対象となる酸性溶液は、有機酸、あるいは無機酸（鉱酸）のいずれも対象とすることができる。
有機酸としては、例えば、クエン酸、シュウ酸、コハク酸、酒石酸、乳酸、マロン酸、ギ酸などが挙げられる。
鉱酸としては、例えば、塩酸、硫酸、硝酸、リン酸などが挙げられる。 <Method for purifying acidic solution>
In the method for purifying an acidic solution of the present invention, the acidic solution is purified using an ion-exchange resin that has been previously purified by bringing it into contact with a specific mineral acid solution.
The acidic solution to be purified can be either an organic acid or an inorganic acid (mineral acid).
Examples of organic acids include citric acid, oxalic acid, succinic acid, tartaric acid, lactic acid, malonic acid, and formic acid.
Mineral acids include, for example, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and the like.

本発明者は、酸性溶液精製時におけるイオン交換樹脂からの金属不純物の溶出を低減するために、酸性溶液の精製に使用する前のイオン交換樹脂（以下、「精製対象のイオン交換樹脂」ともいう）を鉱酸溶液に接触させて精製することを検討したが、接触させる鉱酸溶液自体に金属不純物が含まれていると、イオン交換樹脂内の金属不純物を低減させることができないばかりか、逆にイオン交換樹脂に鉱酸水溶液中の金属不純物を吸着させ増大させてしまう場合がある。それにより、鉱酸溶液接触後のイオン交換樹脂を酸性溶液の精製に使用することによって、かえって被酸性溶液中に多量の金属物質等を溶出させてしまうことが予想される。特に、金属の中でもナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、鉄（Ｆｅ）は、他の金属と比較してイオン交換樹脂内での含有量が多く、鉱酸溶液の接触によっても含有量の低減が困難であることがわかっている。
そこで、精製対象のイオン交換樹脂に、含有金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させることによって、得られる精製イオン交換樹脂に濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物量を、５ｇ／ｍＬ－Ｒ以下とし、かかるイオン交換樹脂を酸性溶液の精製に用いることにより、酸性溶液精製時におけるイオン交換樹脂からの金属不純物の溶出が低減され、不純物濃度が一層低減された酸性溶液の提供が可能となる。 In order to reduce the elution of metal impurities from the ion-exchange resin during purification of the acidic solution, the present inventors used an ion-exchange resin before use for purification of the acidic solution (hereinafter also referred to as "ion-exchange resin to be purified"). ) was considered to be purified by contacting it with a mineral acid solution. In some cases, the metal impurities in the mineral acid aqueous solution are adsorbed to the ion exchange resin and increased. Therefore, it is expected that a large amount of metal substances and the like will rather be eluted into the solution to be acidified by using the ion-exchange resin after contact with the mineral acid solution to purify the acid solution. In particular, among metals, sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) have a higher content in the ion-exchange resin than other metals, and contact with a mineral acid solution It is also known that it is difficult to reduce the content of
Therefore, by contacting the ion-exchange resin to be purified with a mineral acid solution containing 1 mg/L or less of metal impurities and having a concentration of 5% by weight or more, hydrochloric acid having a concentration of 3% by weight is added to the resulting purified ion-exchange resin. The total amount of metal impurities eluted when passing through at 25 times the volume ratio is 5 g / mL-R or less, and by using such an ion exchange resin for purifying an acidic solution, the ion exchange resin when purifying an acidic solution It is possible to provide an acidic solution with a further reduced concentration of impurities by reducing the elution of metal impurities from.

精製対象のイオン交換樹脂としては、カチオン交換樹脂及びアニオン交換樹脂のいずれを用いてもよく、またカチオン交換樹脂とアニオン交換樹脂を組み合わせて用いてもよい。
カチオン樹脂としては、強酸性カチオン交換樹脂（ＳＡＣ）、弱酸性カチオン交換樹脂（ＷＡＣ）、およびキレート樹脂等が挙げられる。 As the ion-exchange resin to be purified, either a cation-exchange resin or an anion-exchange resin may be used, or a cation-exchange resin and an anion-exchange resin may be used in combination.
Cationic resins include strongly acidic cation exchange resins (SAC), weakly acidic cation exchange resins (WAC), chelate resins, and the like.

強酸性カチオン交換樹脂としては、スルホン酸基等の官能基を有するもの、例えば、アンバーライト（登録商標）ＩＲ１２４（官能基：スルホン酸基）（デュポン社製）、アンバーライト（登録商標）２００ＣＴ（官能基：スルホン酸基）（デュポン社製）、アンバーライトＩＲＮ９７Ｈ（官能基：スルホン酸基）（デュポン社製）、オルライト（登録商標）ＤＳ－１（商品名、オルガノ（株）製）（官能基：スルホン酸基）、オルライト（登録商標）ＤＳ－４（商品名、オルガノ（株）製）（官能基：スルホン酸基）等を用いることができる。 As the strongly acidic cation exchange resin, those having a functional group such as a sulfonic acid group, for example, Amberlite (registered trademark) IR124 (functional group: sulfonic acid group) (manufactured by DuPont), Amberlite (registered trademark) 200CT ( Functional group: sulfonic acid group) (manufactured by DuPont), Amberlite IRN97H (functional group: sulfonic acid group) (manufactured by DuPont), Orlite (registered trademark) DS-1 (trade name, manufactured by Organo Corporation) (functional Group: sulfonic acid group), Orlite® DS-4 (trade name, manufactured by Organo Corporation) (functional group: sulfonic acid group), and the like can be used.

弱酸性カチオン交換樹脂としては、カルボキシル基等の官能基を有するもの、例えば、アンバーライト（登録商標）ＩＲＣ７６（官能基．カルボン酸基）（デュポン社製）、アンバーライト（登録商標）ＦＰＣ３５００（官能基．カルボン酸基）（デュポン社製）等を用いることができる。 As the weakly acidic cation exchange resin, those having a functional group such as a carboxyl group, for example, Amberlite (registered trademark) IRC76 (functional group. carboxylic acid group) (manufactured by DuPont), Amberlite (registered trademark) FPC3500 (functional group, carboxylic acid group) (manufactured by DuPont) and the like can be used.

キレート樹脂は、金属イオンとキレート(錯体)を形成することができる官能基を有する樹脂である。この官能基としては、金属イオンとキレート(錯体)を形成することができる官能基であればよく、特に制限はないが、例えば、アミノメチルリン酸基、イミノ二酢酸基、チオール基、ポリアミン基等が挙げられる。キレート樹脂としては、複数の金属種に対する選択性等の観点から、アミノメチルリン酸基またはイミノ二酢酸基をキレート基として有していてもよい。 A chelate resin is a resin having a functional group capable of forming a chelate (complex) with a metal ion. The functional group is not particularly limited as long as it is a functional group capable of forming a chelate (complex) with metal ions. etc. The chelate resin may have an aminomethyl phosphate group or an iminodiacetic acid group as a chelate group from the viewpoint of selectivity for a plurality of metal species.

キレート樹脂としては、例えば、アンバーセップ（登録商標）ＩＲＣ７４７ＵＰＳ（キレート基：アミノメチルリン酸基）、アンバーセップ（登録商標）１ＲＣ７４８（キレート基：イミノ二酢酸基）（いずれもデュポン社製）等を用いることができる。その他、Ｈ形キレート樹脂として、オルライト（登録商標）ＤＳ－２１（商品名、オルガノ（株）製）（キレート基：アミノメチルリン酸基）、オルライト（登録商標） ＤＳ－２２（商品名、オルガノ（株）製）（キレート基：イミノ二酢酸基）を用いてもよい。 Examples of the chelating resin include Ambersep (registered trademark) IRC747UPS (chelating group: aminomethyl phosphate group), Ambersep (registered trademark) 1RC748 (chelating group: iminodiacetic acid group) (both manufactured by DuPont), and the like. can be used. Other examples of H-type chelate resins include Orlyte (registered trademark) DS-21 (trade name, manufactured by Organo Co., Ltd.) (chelate group: aminomethyl phosphate group), Orlyte (registered trademark) DS-22 (trade name, Organo Co., Ltd.) (chelate group: iminodiacetic acid group) may also be used.

アンバーセップ（登録商標）ＩＲＣ７４７ＵＰＳ、アンバーセップ（登録商標）ＩＲＣ７４８のイオン形はＮａ形が基準であるが、上記の方法で鉱酸溶液を接触させることにより、イオン形はＮａ形からＨ形に変換される。 The ionic form of Ambersep (registered trademark) IRC747UPS and Ambersep (registered trademark) IRC748 is based on the Na form, but the ionic form is converted from the Na form to the H form by contacting with a mineral acid solution by the above method. be done.

アニオン交換樹脂としては、強塩基性アニオン交換樹脂（ＳＢＡ）であっても、弱塩基性アニオン交換樹脂（ＷＢＡ）であってもよく、弱塩基性アニオン交換樹脂は、ホウ素選択性アニオン交換樹脂であってもよい。
強塩基性アニオン交換樹脂としては、オルライト（登録商標）ＤＳ－２（商品名、オルガノ（株）製）、オルライト（登録商標）ＤＳ－５（商品名、オルガノ（株）製）等が挙げられる。
また、弱塩基性アニオン交換樹脂としては、オルライト（登録商標）ＤＳ－６２（商品名、オルガノ（株）製）のほか、グルカミン基を官能基に持つホウ素選択性アニオン交換樹脂である、アンバーライト（登録商標）ＩＲＡ７４３（デュポン社製）が挙げられる。
なお、アニオン交換樹脂は、ＯＨ形のアニオン交換樹脂でも、酸形のアニオン交換樹脂でもよいが、精製対象と同じ酸形が好ましく用いられる。 The anion exchange resin may be a strongly basic anion exchange resin (SBA) or a weakly basic anion exchange resin (WBA), the weakly basic anion exchange resin being a boron selective anion exchange resin. There may be.
Strongly basic anion exchange resins include Orlyte (registered trademark) DS-2 (trade name, manufactured by Organo Corporation), Orlyte (registered trademark) DS-5 (trade name, manufactured by Organo Corporation), and the like. .
As the weakly basic anion exchange resin, Orlyte (registered trademark) DS-62 (trade name, manufactured by Organo Co., Ltd.), and Amberlite, which is a boron-selective anion exchange resin having a glucamine group as a functional group. (registered trademark) IRA743 (manufactured by DuPont).
The anion exchange resin may be an OH-type anion exchange resin or an acid-type anion exchange resin, but the same acid-type resin as that to be purified is preferably used.

酸性溶液の精製において、イオン交換樹脂は、カチオン交換樹脂とアニオン交換樹脂を組み合わせて使用してもよく、そのような組み合わせとしては、アニオン交換樹脂－カチオン交換樹脂の順の組み合わせ、カチオン交換樹脂－アニオン交換樹脂の順の組み合わせ、カチオン交換樹脂又はアニオン交換樹脂－カチオン交換樹脂及びアニオン交換樹脂の混床の順の組み合わせ、カチオン交換樹脂及びアニオン交換樹脂の混床－カチオン交換樹脂又はアニオン交換樹脂の順の組み合わせが挙げられる。
アニオン交換樹脂とカチオン交換樹脂とを混床で用いてもよいし、アニオン交換樹脂→ カチオン交換樹脂の順に処理してもよい。酸性溶液中でイオン交換しやすいアニオン交換樹脂を用いて先にアニオン成分を除去した後、カチオン交換樹脂を用いてカチオン成分を除去することが効果的である。両性イオンが存在すれば、先にアニオン交換樹脂で低減した方が、後段のカチオン交換樹脂への負荷が減る。また、カチオン交換樹脂は、カチオン交換基が金属不純物を捕捉するため、ポリッシャーとして後段に配置してもよい。カチオン交換樹脂の代わりにキレート樹脂を用いてもよいし、アニオン交換樹脂の後段にカチオン交換樹脂とキレート樹脂とを組み合わせて用いてもよい。
またアニオン樹脂を用いず、強酸性カチオン交換樹脂、弱酸性カチオン交換樹脂、およびキレート樹脂のうち、２種以上を組み合わせ使用してもよい。
なおイオン交換樹脂には、酸性溶液の精製に使用後、後述する再生処理を実施された再生イオン交換樹脂も含まれる。
カチオン交換樹脂、アニオン交換樹脂の母体は、例えば、スチレン樹脂、アクリル樹脂等が挙げられる。 In the purification of acidic solutions, ion exchange resins may be used in combination with cation exchange resins and anion exchange resins, such combinations being an anion exchange resin--cation exchange resin order combination, cation exchange resin-- Sequential combinations of anion exchange resins, sequential combinations of cation exchange resins or anion exchange resins - mixed beds of cation exchange resins and anion exchange resins, mixed beds of cation exchange resins and anion exchange resins - cation exchange resins or anion exchange resins An order combination is mentioned.
The anion exchange resin and the cation exchange resin may be used in a mixed bed, or the treatment may be performed in the order of the anion exchange resin and the cation exchange resin. It is effective to first remove the anion component by using an anion exchange resin that easily exchanges ions in an acidic solution, and then remove the cation component by using a cation exchange resin. If amphoteric ions are present, reducing them in the anion exchange resin first reduces the load on the cation exchange resin in the subsequent stage. Moreover, since the cation exchange group captures metal impurities, the cation exchange resin may be arranged as a polisher in the subsequent stage. A chelate resin may be used instead of the cation exchange resin, or a combination of the cation exchange resin and the chelate resin may be used after the anion exchange resin.
Two or more of strongly acidic cation exchange resins, weakly acidic cation exchange resins, and chelate resins may be used in combination without using anion resins.
The ion-exchange resin also includes a regenerated ion-exchange resin that has undergone a regeneration treatment described later after being used for purifying an acidic solution.
Examples of base materials for cation exchange resins and anion exchange resins include styrene resins and acrylic resins.

これらのイオン交換樹脂の中では、多くの金属不純物がカチオン性であることから、強酸性イオン交換樹脂を用いることが好ましく、特に母体の強度が高さや清浄度の点から、スチレン型強酸性イオン交換樹脂を用いることより好ましい。
強酸性イオン交換樹脂は、事前にＨ形に調製したものを用いると、カチオン性不純物とイオン交換基のＨ＋が交換されることで不純物を低減することができるが、Ｈ＋の増加は酸溶液の組成に与える影響が小さいため好ましい。
なお、酸性溶液が有機酸であり、イオン交換樹脂として、アニオン交換樹脂を用いる場合は、アクリル系アニオン交換樹脂を用いることが好ましい。
有機酸中ではアニオン交換樹脂のイオン形が酸形および金属イオン形に変換されるため、イオン形の変換による膨潤収縮が起こり、通液と再生を繰り返すと樹脂が破砕する場合がある。膨潤収縮に強く、柔軟性がある母体であり、例えばＯＨ形から有機酸形へ膨潤しても破砕が少ない等の点から、アニオン交換樹脂は膨潤収縮に強いアクリル樹脂を含んで構成されていてもよい。また、膨潤収縮が大きいアクリル系アニオン交換樹脂を用いることによって、圧力変動を検知しやすい。 Among these ion exchange resins, it is preferable to use strongly acidic ion exchange resins because many metal impurities are cationic. It is more preferable to use an exchange resin.
If a strongly acidic ion exchange resin prepared in advance to H form is used, it is possible to reduce impurities by exchanging cationic impurities with H + of the ion exchange group, but an increase in H + increases the acid solution. It is preferable because it has little effect on the composition.
When the acidic solution is an organic acid and an anion exchange resin is used as the ion exchange resin, it is preferable to use an acrylic anion exchange resin.
In an organic acid, the ion form of the anion exchange resin is converted into the acid form and the metal ion form, so swelling and shrinkage occur due to the conversion of the ion form, and the resin may be crushed after repeated feeding and regeneration. The anion-exchange resin is composed of an acrylic resin that is resistant to swelling and shrinkage because it is a matrix that is resistant to swelling and shrinkage and has flexibility. good too. In addition, by using an acrylic anion exchange resin that swells and shrinks greatly, it is easy to detect pressure fluctuations.

イオン交換樹脂は、調和平均径が１００μｍ以上４００μｍ以下であるものを使用することが好ましい。粒径がこの範囲にあると、表面積が大きく不純物イオンが官能基へ近づきやすくなり、金属除去性が良くなるため好ましい。また後述するイオン交換樹脂の再生においても、表面積が大きく再生薬液が官能基へ近づきやすいため、再生されやすくなることから好ましい。
なお、本発明において、イオン交換樹脂の平均粒径は、レーザー回析式粒度分布計を用い測定される調和平均径を指す。 It is preferable to use an ion exchange resin having a harmonic mean diameter of 100 μm or more and 400 μm or less. When the particle size is in this range, the surface area is large, impurity ions can easily approach the functional group, and the metal removal property is improved, which is preferable. In addition, in the regeneration of the ion-exchange resin, which will be described later, the surface area is large and the regenerating chemical solution can easily approach the functional groups, which facilitates regeneration, which is preferable.
In the present invention, the average particle diameter of the ion exchange resin refers to the harmonic mean diameter measured using a laser diffraction particle size distribution meter.

またイオン交換樹脂は、平均粒径が前記の範囲にあることに加えて、架橋度（ジビニルベンゼン含有量）が２％以上１３％以下であるものを使用することが好ましい。架橋度がこの範囲にあると、樹脂内部の拡散性が増し、さらに金属除去性やイオン交換樹脂の再生されやすさが増すことから好ましい。 In addition to having an average particle size within the above range, the ion exchange resin preferably has a degree of cross-linking (content of divinylbenzene) of 2% or more and 13% or less. When the degree of cross-linking is within this range, the diffusibility inside the resin is increased, and the metal removal property and the easiness of regeneration of the ion exchange resin are increased, which is preferable.

以上の点から、イオン交換樹脂としては、事前にＨ形に調製した強酸性カチオン樹脂であって、樹脂母体がスチレンであり、平均粒径１００μｍ以上４００μｍ以下であり、かつ架橋度（ジビニルベンゼン含有量）が２％以上１３％以下である強酸性カチオン交換樹脂を用いることがより一層好ましい。 From the above points, the ion exchange resin is a strongly acidic cation resin prepared in advance into an H form, the resin matrix is styrene, the average particle size is 100 μm or more and 400 μm or less, and the degree of cross-linking (containing divinylbenzene amount) is 2% or more and 13% or less.

イオン交換樹脂の精製に用いられる鉱酸溶液は、無機酸の溶液である。鉱酸としては、例えば、塩酸、硫酸、硝酸等が挙げられる。溶液を構成する溶媒としては、例えは、純水（比抵抗：約１０ＭＱ・ｃｍ）、超純水（比抵抗：約１８ＭＱ・ｃｍ）等の水である。 Mineral acid solutions used to purify ion exchange resins are solutions of inorganic acids. Mineral acids include, for example, hydrochloric acid, sulfuric acid, nitric acid and the like. Examples of the solvent that constitutes the solution include water such as pure water (specific resistance: about 10 MQ·cm) and ultrapure water (specific resistance: about 18 MQ·cm).

イオン交換樹脂の精製で使用される鉱酸溶液中の含有金属不純物量は、１ｍｇ／Ｌ以下であり、少なければ少ないほどよく、０．５ｍｇ／Ｌ以下であってもよく、０．２ｍｇ／Ｌ以下であってもよい。鉱酸溶液中の含有金属不純物量が１ｍｇ／Ｌを超える場合は、充分なイオン交換樹脂内の金属不純物量低減効果を得ることができない。 The amount of metal impurities contained in the mineral acid solution used in the purification of the ion exchange resin is 1 mg/L or less, and the lower the better, and may be 0.5 mg/L or less, or 0.2 mg/L. It may be below. If the amount of metal impurities contained in the mineral acid solution exceeds 1 mg/L, a sufficient effect of reducing the amount of metal impurities in the ion exchange resin cannot be obtained.

鉱酸溶液の鉱酸濃度は、５重量％以上であり、１０重量％以上であってもよい。鉱酸溶液の鉱酸の濃度が５重量％未満の場合は、充分なイオン交換樹脂内の金属不純物量低減効果を得ることができない。鉱酸溶液の鉱酸の濃度の上限は、例えば、３７重量％である。 The mineral acid concentration of the mineral acid solution is 5% by weight or more, and may be 10% by weight or more. If the concentration of mineral acid in the mineral acid solution is less than 5% by weight, a sufficient effect of reducing the amount of metal impurities in the ion exchange resin cannot be obtained. The upper limit of the mineral acid concentration of the mineral acid solution is, for example, 37% by weight.

ここで金属不純物とは金属の他に金属不純物イオンをも含む概念であり、代表的なものとして例えばナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、および鉄（Ｆｅ）等が挙げられる。 Here, the metal impurity is a concept that includes not only metal but also metal impurity ions, and representative examples include sodium (Na), calcium (Ca), magnesium (Mg), iron (Fe), and the like. .

イオン交換樹脂の精製で使用される鉱酸溶液におけるナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、および鉄（Ｆｅ）の各含有量は、少なければ少ないほどよく、それぞれ２００μｇ／Ｌ以下であってもよく、それぞれ１００μｇ／Ｌ以下であってもよい。
これらの金属不純物含有量が少ない鉱酸溶液をカチオン交換樹脂に接触させることにより、確実かつ効果的にイオン交換樹脂内のナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、および鉄（Ｆｅ）等の金属不純物の含有量を低減させることができる。 The lower the content of sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) in the mineral acid solution used in the purification of the ion-exchange resin, the better, each of which is 200 μg/L or less. and each may be 100 μg/L or less.
By contacting a cation exchange resin with a mineral acid solution containing a small amount of these metal impurities, sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) in the ion exchange resin can be reliably and effectively removed. ) can be reduced.

イオン交換樹脂の精製においてイオン交換樹脂と接触させる鉱酸溶液の温度は、例えば、０～４０℃の範囲である。 The temperature of the mineral acid solution that is brought into contact with the ion-exchange resin in the purification of the ion-exchange resin is, for example, in the range of 0 to 40°C.

イオン交換樹脂の精製によって得られる精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量を、５μｇ／ｍＬ－Ｒ以下とすることができる。全金属不純物溶出量は、少なければ少ないほどよく、１μｇ／ｍＬ－Ｒ以下であってもよい。この全金属不純物溶出量を５μｇ／ｍＬ－Ｒ以下とすることによって、このイオン交換樹脂を酸性溶液の精製に用いた場合のイオン交換樹脂から酸性溶液中のこれら金属不純物の溶出量を低減することができ、その結果、半導体製造工程に好適な、より一層不純物濃度が低減された酸性溶液を得ることができる。 The eluted amount of all metal impurities eluted when hydrochloric acid with a concentration of 3% by weight is passed through a purified ion-exchange resin obtained by purification of the ion-exchange resin at 25 times the volume ratio is 5 μg/mL-R or less. can be done. The elution amount of all metal impurities should be as low as possible, and may be 1 μg/mL-R or less. By setting the elution amount of all metal impurities to 5 μg/mL-R or less, the elution amount of these metal impurities in the acidic solution from the ion-exchange resin when the ion-exchange resin is used to purify the acidic solution is reduced. As a result, it is possible to obtain an acidic solution with a further reduced impurity concentration, which is suitable for the semiconductor manufacturing process.

溶出する金属不純物は、ナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、または鉄（Ｆｅ）のうち少なくともいずれか１つの金属を含んでもよい。 The eluted metal impurities may include at least one of sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe).

イオン交換樹脂の精製の後に、鉱酸溶液を接触させた精製イオン交換樹脂を純水、超純水等の洗浄水で洗浄する洗浄工程を含んでもよい。精製イオン交換樹脂を、鉱酸溶液に接触させた後に純水、超純水等の洗浄水で洗浄することによって、精製イオン交換樹脂から鉱酸溶液を除去する際に、金属不純物の再汚染等を抑制することができる。 After purification of the ion exchange resin, a washing step may be included in which the purified ion exchange resin contacted with the mineral acid solution is washed with washing water such as pure water or ultrapure water. By washing the purified ion-exchange resin with washing water such as pure water or ultrapure water after contacting it with the mineral acid solution, when removing the mineral acid solution from the purified ion-exchange resin, recontamination of metal impurities, etc. can be suppressed.

洗浄工程においてカチオン交換樹脂と接触させる洗浄水としては、純水、超純水等が挙げられ、精製後の汚染抑制等の点から、超純水であってもよい。 The washing water to be brought into contact with the cation exchange resin in the washing step includes pure water, ultrapure water, and the like, and ultrapure water may be used from the viewpoint of preventing contamination after purification.

洗浄工程においてカチオン交換樹脂と接触させる洗浄水の温度は、例えば、１～８０℃であり、１５～３０℃が好ましい。 The temperature of the washing water brought into contact with the cation exchange resin in the washing step is, for example, 1 to 80°C, preferably 15 to 30°C.

＜イオン交換樹脂の再生＞
本発明では、以上説明した工程により得られた精製イオン交換樹脂を使用して酸性溶液の精製を実施するものであるが、精製に使用したイオン交換樹脂、特にカチオン交換樹脂は、再生処理を実施した後、再び、精製対象のイオン交換樹脂として精製処理を行い、再び、酸性溶液の精製に利用することができる。
精製に使用したイオン交換樹脂の再生は、塩酸、硫酸等の鉱酸溶液を用いて再生処理し、鉱酸を水洗浄によって除去した後、再度対象酸溶液を精製することにより実施する。鉱酸濃度は１規定以上の濃度が好ましい。特に本発明のイオン交換樹脂は金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製しているため、再生する場合も同様の方法を用いて再生することが望ましい。酸濃度や酸通液量は再生された樹脂の金属含有量が濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量を元に適宜決めれば良い。
なお、イオン交換樹脂としてアニオン交換樹脂を使用した場合、酸性溶液の精製過程において、鉱酸形に変換されるので、必ずしも前記方法で再生する必要は無い。代わりに、１規定以上の濃度の塩化ナトリウム溶液や、水酸化ナトリウム溶液、水酸化テトラメチルアンモニウム（ＴＭＡＨ）溶液で再生しても良い。再生した後、処理対象となる酸または有機酸形に変換して使用しても良い。その場合に使用する前記酸または有機酸は、処理対象液よりも金属濃度が低いことが好ましい。 <Regeneration of ion exchange resin>
In the present invention, the purified ion exchange resin obtained by the steps described above is used to purify the acidic solution. After that, it is again subjected to purification treatment as an ion-exchange resin to be purified, and can be used again to purify an acidic solution.
Regeneration of the ion-exchange resin used for refining is carried out by regenerating with a mineral acid solution such as hydrochloric acid or sulfuric acid, removing the mineral acid by washing with water, and then purifying the target acid solution again. The concentration of mineral acid is preferably 1N or more. In particular, since the ion exchange resin of the present invention is purified by contacting with a mineral acid solution having a metal impurity amount of 1 mg/L or less and a concentration of 5% by weight or more, the same method is used to regenerate the resin. is desirable. The acid concentration and the amount of acid flow may be appropriately determined based on the eluted amount of all metal impurities eluted when hydrochloric acid having a metal content of 3% by weight of the regenerated resin is passed through in an amount 25 times the volume ratio.
When an anion exchange resin is used as the ion exchange resin, it is converted into a mineral acid form in the process of purifying the acidic solution, so it is not always necessary to regenerate it by the above method. Instead, it may be regenerated with a sodium chloride solution having a concentration of 1N or more, a sodium hydroxide solution, or a tetramethylammonium hydroxide (TMAH) solution. After regeneration, it may be used after being converted into the acid or organic acid form to be treated. The acid or organic acid used in that case preferably has a metal concentration lower than that of the liquid to be treated.

有機酸精製に使用後のイオン交換樹脂を再生する場合は、再生後のイオン交換樹脂に有機酸が残留していないか確認するため、使用前に純水でイオン交換樹脂を洗浄し、洗浄水の全有機炭素（ＴＯＣ）が予め設定した値を超過しないことを確認することで、再生の可否を判断できる。鉱酸と異なり、有機酸はＴＯＣとして検出可能であるため、樹脂に残留した有機酸をＴＯＣとして検出し樹脂の洗浄度の指標として品質管理に適用できる。 When regenerating the ion-exchange resin after it has been used for refining organic acids, wash the ion-exchange resin with pure water before use in order to confirm that no organic acid remains in the regenerated ion-exchange resin. By confirming that the total organic carbon (TOC) of the waste does not exceed a preset value, it is possible to judge whether the regeneration is possible or not. Unlike mineral acids, organic acids can be detected as TOC, so the organic acids remaining in the resin can be detected as TOC and applied to quality control as an indicator of the degree of cleaning of the resin.

本発明の精製方法では、微粒子除去膜を使用する工程を設けてもよい。例えば、精製過程の前段、即ち、イオン交換樹脂による精製を実施する前の工程で、微粒子除去膜を使用する工程を設けると、酸性溶液中に含まれる微粒子がイオン交換樹脂母体に吸着する等の汚染を抑制することができる。またイオン交換樹脂による精製後の工程で、微粒子除去膜を使用する工程を設けると、酸性溶液中の溶出金属不純物のみならず、不純物微粒子も低減することができる。また微粒子除去膜を使用する工程を、イオン交換樹脂による精製を実施する前及び後の工程に設けると、前記両方の効果を得ることができ、より一層高純度な酸性溶液を得ることができる。 In the purification method of the present invention, a step of using a fine particle removal membrane may be provided. For example, if a step of using a fine particle removal membrane is provided in the first stage of the purification process, that is, before the purification by the ion exchange resin is performed, fine particles contained in the acidic solution are adsorbed to the ion exchange resin matrix. Contamination can be suppressed. Further, if a step of using a fine particle removing membrane is provided in the step after purification by ion exchange resin, not only eluted metal impurities in the acidic solution but also impurity fine particles can be reduced. If a step of using a fine particle-removing membrane is provided before and after purification with an ion-exchange resin, both of the above effects can be obtained, and an acidic solution of even higher purity can be obtained.

以上説明した本発明の精製方法は、対象のイオン交換樹脂に、金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することにより精製カチオン交換樹脂を得るイオン交換樹脂精製手段であって、前記精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量は、５μｇ／ｍＬ―Ｒ以下である、イオン交換樹脂精製手段と、
前記精製イオン交換樹脂を用いて酸性溶液を精製する、酸性溶液精製手段と、
を備えることを特徴とする酸性溶液精製装置、具体的には、
精製対象のイオン交換樹脂に、含有金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することによって精製イオン交換樹脂を得る精製手段として、イオン交換樹脂カラム（第１のカラム）を備え、この第１のカラムには、イオン交換樹脂を精製するための鉱酸を供給するための配管、精製処理後の廃液を排出するための配管が設けられている。
また酸性溶液精製装置は、さらにイオン交換樹脂精製手段により得られた精製イオン交換樹脂を精製対象の処理液を接触させて精製する酸性溶液精製手段として、イオン交換樹脂カラム（第２のカラム）を備え、この第２のカラムには、精製対象の酸性溶液を供給するための配管、精製処理後の酸性溶液を排出するための配管が設けられている。
酸性溶液精製装置は、精製処理後のイオン交換樹脂を再生するための再生手段が備えられてもよい。 In the purification method of the present invention described above, a purified cation exchange resin is purified by contacting a target ion exchange resin with a mineral acid solution having a metal impurity amount of 1 mg / L or less and a concentration of 5% by weight or more. The amount of all metal impurities eluted when 25 times the volume ratio of hydrochloric acid having a concentration of 3% by weight is passed through the purification ion exchange resin is 5 μg/mL-R or less. An ion exchange resin purification means,
an acidic solution purifying means for purifying an acidic solution using the purified ion exchange resin;
An acidic solution purification device characterized by comprising
As a purification means for obtaining a purified ion-exchange resin by contacting the ion-exchange resin to be purified with a mineral acid solution having a metal impurity content of 1 mg / L or less and a concentration of 5% by weight or more for purification, an ion-exchange resin A column (first column) is provided, and the first column is provided with a pipe for supplying mineral acid for refining the ion exchange resin and a pipe for discharging waste liquid after refining treatment. there is
The acidic solution purifying apparatus further includes an ion exchange resin column (second column) as an acidic solution purifying means for purifying the purified ion exchange resin obtained by the ion exchange resin purifying means by contacting the treated liquid to be purified. In addition, the second column is provided with a pipe for supplying the acidic solution to be purified and a pipe for discharging the acidic solution after the purification treatment.
The acidic solution purifier may be provided with regeneration means for regenerating the ion-exchange resin after the purification treatment.

以下、実施例により本発明を具体的に説明するが本発明は以下の実施例に限定されない。 EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

＜イオン交換樹脂＞
用いたイオン交換樹脂は以下のとおりである。

Figure 2023059066000001
試験番号１及び２：強酸性カチオン交換樹脂、粒径は、純水製造で使用される一般的な範囲
試験番号３：小粒径、かつ低架橋の強酸性カチオン樹脂
試験番号４：小粒径の強酸性カチオン樹脂
試験番号５：高架橋度の強カチオン樹脂、粒径は、純水製造で使用される一般的な範囲
試験番号６：キレート樹脂、粒径は、純水製造で使用される一般的な範囲
試験番号７：強塩基性アニオン交換樹脂、粒径は、純水製造で使用される一般的な範囲
試験番号８：試験番号４と同樹脂。ただし金属溶出量は５μｇ／ｍＬ―Ｒ以下を満たさない。 <Ion exchange resin>
The ion exchange resins used are as follows.
Figure 2023059066000001
 Test Nos. 1 and 2: Strongly acidic cation exchange resin, particle size is in the general range used in pure water production Test No. 3: Small particle size and low cross-linking strongly acidic cation resin Test No. 4: Small particle size Strongly acidic cation resin Test No. 5: Highly crosslinked strong cation resin, particle size is the general range used in pure water production Test No. 6: Chelate resin, particle size is general used in pure water production Typical Range Test No. 7: Strongly basic anion exchange resin, particle size is typical range used in pure water production Test No. 8: Same resin as Test No. 4. However, the metal elution amount does not satisfy 5 μg/mL-R or less.

＜イオン交換樹脂の精製＞
試験番号１～７のイオン交換樹脂は、塩酸を用いて精製し、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量が、５μｇ／ｍＬ―Ｒ以下を満たすまで精製した。
試験番号８の樹脂は、塩酸を用いてＨ形に変換する処理を施しているが、前記の条件を満たさない（全金属不純物溶出量が、５μｇ／ｍＬ―Ｒ以上）。 <Purification of ion exchange resin>
The ion exchange resins of test numbers 1 to 7 were purified using hydrochloric acid, and the amount of all metal impurities eluted when passing hydrochloric acid with a concentration of 3% by weight at 25 times the volume ratio was 5 μg / mL-R. It was purified until the following was satisfied.
The resin of Test No. 8 was treated with hydrochloric acid to convert it to the H form, but it did not meet the above conditions (the eluted amount of all metal impurities was 5 µg/mL-R or more).

１．有機酸中の金属除去試験
以下の試験手順に従い、各種イオン交換樹脂の有機酸における金属除去性能を比較した。有機酸としては、クエン酸（９９．９％、和光特級 ５００ｇ，富士フイルム和光純薬社製）を用いた。 1. Metal removal test in organic acid
Various ion exchange resins were compared for metal removal performance in organic acids according to the following test procedure. As the organic acid, citric acid (99.9%, Wako special grade 500 g, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was used.

＜試験手順＞
事前洗浄した高密度ポリエチレン（ＨＤＰＥ）製バッチ容器に各試験のイオン交換樹脂の水湿潤品を投入する。３０％クエン酸を樹脂体積の５倍量バッチ容器へ移し、５分ごとに約１０秒間容器を攪拌し、１５分間浸漬する操作を２回繰り返し、イオン交換樹脂内の水分を有機酸と交換した。
その後、３０％クエン酸を樹脂体積の１０倍量バッチ容器へ移し、１５分ごとに約１０秒間容器を攪拌する操作を４回繰り返した。上澄み液を適宜希釈し、ＩＣＰ－ＭＳを用いて金属濃度を分析した。 <Test procedure>
A pre-cleaned high density polyethylene (HDPE) batch container is charged with the wet ion exchange resin for each test. Transfer 30% citric acid to a batch container in an amount 5 times the volume of the resin, stir the container for about 10 seconds every 5 minutes, and repeat the operation of immersing for 15 minutes twice to replace the water in the ion exchange resin with organic acid. .
Thereafter, 30% citric acid was transferred to a batch container in an amount 10 times the resin volume, and the container was stirred for about 10 seconds every 15 minutes, and this operation was repeated four times. The supernatant was diluted appropriately and analyzed for metal concentration using ICP-MS.

＜結果＞
イオン交換樹脂処理前のクエン酸溶液中の金属濃度に対する除去率を表２に示した。
強酸性カチオン交換樹脂にとして一般的な粒径（＞４００μｍ以上）と比べると、小粒径樹脂（＜４００μｍ）の方が、Ｍｇ、Ｃａにおいて良好な除去率を示した。その他、Ｎａ、Ａｌ、Ｆｅに関しても５０％以上の除去率を示した。ただしＡｓはいずれの強酸性カチオン樹脂でも除去できず、強塩基性アニオン樹脂で低減することができたため、アニオン形態で存在したと考えられる。 <Results>
Table 2 shows the removal rate with respect to the metal concentration in the citric acid solution before ion exchange resin treatment.
Small particle size resins (<400 μm) showed better removal rates for Mg and Ca than particle sizes (>400 μm or more) typical for strongly acidic cation exchange resins. In addition, removal rates of 50% or more were shown for Na, Al, and Fe. However, As could not be removed with any of the strongly acidic cation resins and could be reduced with the strongly basic anion resin, it is believed that As existed in the anion form.

２．再生後の金属除去性
塩酸による以下の再生方法による再生後の各種イオン交換樹脂について、前記１と同様の手順に従い、有機酸クエン酸（９９．９％、和光特級 ５００ｇ，富士フイルム和光純薬社製）における金属除去性能を比較した。なお、前記１の試験において、金属除去性能が好ましくなかったキレート樹脂と強アニオン樹脂は本試験から省いた。 2. Metal removal after regeneration
For various ion-exchange resins after regeneration by the following regeneration method with hydrochloric acid, according to the same procedure as in 1 above, metal removal performance in organic acid citric acid (99.9%, Wako special grade 500 g, manufactured by Fujifilm Wako Pure Chemical Co., Ltd.) compared. The chelate resin and the strong anion resin, which had unfavorable metal removal performance in Test 1, were omitted from this test.

＜再生方法＞
バッチ試験を実施したイオン交換樹脂を超純水で十分洗浄した後、体積の５倍量の１ｍｏｌ／Ｌの塩酸に１５分浸漬する操作を６回繰り返した。その後超純水で十分洗浄し、再生樹脂とした。 <Playback method>
The ion-exchange resin subjected to the batch test was thoroughly washed with ultrapure water and then immersed in 5 times the volume of 1 mol/L hydrochloric acid for 15 minutes, which was repeated six times. After that, it was sufficiently washed with ultrapure water to obtain a recycled resin.

＜結果＞
樹脂処理前のクエン酸溶液中の金属不純物の除去率を表３に示し、表２と表３の差を図１に棒グラフとしても示した。再生前後の除去率の差が大きいと、再生が不十分でバッチ試験２回目の金属除去性が低下していることを示す。
表２、３及び図１より、Ｎａ金属除去率の差を比較すると、小粒径樹脂である試験番号３、４のイオン交換樹脂は再生の影響をほとんど受けていないことが分かった。
またＭｇ、Ｃａ、Ｆｅの除去率も、小粒径樹脂である試験番号３、４のイオン交換樹脂は他のイオン交換樹脂よりも除去率の差が小さく、良好な結果を示した。小粒径樹脂同士を比較すると、Ｍｇ、Ａｌ、Ｃａの除去率は低架橋である試験番号４のイオン交換樹脂の方が除去率の差が小さく、再生後もより安定した除去性能を示した。
よって小粒径樹脂は通常の粒径の樹脂よりも有機酸精製及び再生工程を伴う有機酸精製により適しており、特に低架橋の小粒径樹脂はより優れた性能を示すことが分かった。 <Results>
The removal rate of metal impurities in the citric acid solution before resin treatment is shown in Table 3, and the difference between Tables 2 and 3 is also shown as a bar graph in FIG. A large difference in removal rate before and after regeneration indicates that regeneration was insufficient and the metal removal performance in the second batch test was lowered.
From Tables 2 and 3 and FIG. 1, it was found that the ion exchange resins of Test Nos. 3 and 4, which are small particle size resins, were hardly affected by regeneration when comparing the difference in Na metal removal rate.
In terms of the removal rate of Mg, Ca and Fe, the ion exchange resins of Test Nos. 3 and 4, which are small particle size resins, showed a smaller difference in the removal rate than the other ion exchange resins, showing favorable results. Comparing the small particle size resins, the ion exchange resin of Test No. 4, which has low cross-linking, showed a smaller difference in the removal rate of Mg, Al, and Ca, and exhibited more stable removal performance even after regeneration. .
Therefore, it was found that the small particle size resin is more suitable than the normal particle size resin for organic acid refining and organic acid refining involving regeneration steps, and in particular, the low crosslinked small particle size resin exhibits superior performance.

３．鉱酸からの金属除去試験
＜試験手順＞
事前洗浄したＨＤＰＥ製バッチ容器に各試験のイオン交換樹脂の湿潤品を投入する。３．５％塩酸を樹脂体積の１０倍量バッチ容器へ移し、１５分ごとに約１０秒間容器を攪拌する操作を４回繰り返した。上澄み液を適宜希釈し、ＩＣＰ－ＭＳを用いて金属濃度を分析した。 3. Metal removal test from mineral acids
<Test procedure>
A pre-cleaned HDPE batch container is charged with the wet ion exchange resin for each test. The operation of transferring 3.5% hydrochloric acid to a batch container in an amount 10 times the resin volume and stirring the container for about 10 seconds every 15 minutes was repeated four times. The supernatant was diluted appropriately and analyzed for metal concentration using ICP-MS.

＜結果＞
イオン交換樹脂処理前の塩酸溶液中の金属濃度に対する除去率を表５に示した。
濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量を、５μｇ／ｍＬ―Ｒ以下に低減した試験番号１、４のイオン交換樹脂は、金属低減効果が確認できた。塩酸精製に関しては、あまり粒径や架橋度の差は見られなかったが、どちらのイオン交換樹脂も一定の低減効果が得られた。
しかし金属不純物溶出量が５μｇ／ｍＬ―Ｒ以下を満たさなかった試験番号８のイオン交換樹脂は、処理前よりも樹脂から溶出する金属で処理液中の金属濃度が上昇することが確認できた。 <Results>
Table 5 shows the removal rate with respect to the metal concentration in the hydrochloric acid solution before ion exchange resin treatment.
The ion-exchange resins of Test Nos. 1 and 4, which reduced the elution amount of all metal impurities to 5 μg/mL-R or less when 25 times the volume ratio of hydrochloric acid with a concentration of 3% by weight was passed through, had a metal reduction effect. was confirmed. As for the purification of hydrochloric acid, there was not much difference in the particle size and the degree of cross-linking, but both ion-exchange resins had a certain reduction effect.
However, for the ion-exchange resin of Test No. 8, in which the amount of eluted metal impurities did not satisfy the condition of 5 μg/mL-R or less, it was confirmed that the metal eluted from the resin increased the metal concentration in the treatment liquid compared to before the treatment.

Figure 2023059066000002
Figure 2023059066000002

Figure 2023059066000003
Figure 2023059066000003

Figure 2023059066000004
Figure 2023059066000004

Claims (8)

イオン交換樹脂を使用する酸性溶液の精製方法であって、
前記イオン交換樹脂は、精製対象のイオン交換樹脂に、金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することにより得られる精製イオン交換樹脂であって、前記精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量は、５μｇ／ｍＬ―Ｒ以下であることを特徴とする酸性溶液の精製方法。 A method for purifying an acidic solution using an ion exchange resin, comprising:
The ion-exchange resin is a purified ion-exchange resin obtained by contacting an ion-exchange resin to be purified with a mineral acid solution having a metal impurity amount of 1 mg/L or less and a concentration of 5% by weight or more for purification. The total amount of eluted metal impurities eluted when hydrochloric acid having a concentration of 3% by weight is passed through the purified ion exchange resin at a volume ratio of 25 times is 5 μg / mL-R or less. A method for purifying a solution. 前記鉱酸溶液におけるナトリウム（Ｎａ）、カルシウム（Ｃａ）、マグネシウム（Ｍｇ）、および鉄（Ｆｅ）の含有量は、それぞれ２００μｇ／Ｌ以下であることを特徴とする請求項１に記載の酸性溶液の精製方法。 2. The acidic solution according to claim 1, wherein the contents of sodium (Na), calcium (Ca), magnesium (Mg), and iron (Fe) in the mineral acid solution are each 200 μg/L or less. purification method. 前記イオン交換樹脂は、スチレン型強酸性イオン交換樹脂を含むことを特徴とする請求項１又は２に記載の酸性溶液の精製方法。 3. The method for purifying an acidic solution according to claim 1, wherein the ion exchange resin contains a styrene-type strongly acidic ion exchange resin. 前記スチレン型強酸性イオン交換樹脂の調和平均径が、１００μｍ以上４００μｍ以下であることを特徴とする請求項１～３のいずれか１項に記載の酸性溶液の精製方法。 The method for purifying an acidic solution according to any one of claims 1 to 3, wherein the styrene-type strongly acidic ion exchange resin has a harmonic mean diameter of 100 µm or more and 400 µm or less. 請求項１～４のいずれか１項に記載の精製方法を用いて酸溶液を精製した後のイオン交換樹脂を、鉱酸溶液に接触させた後、洗浄水のＴＯＣが３０ｐｐｂ以下に達するまで水洗浄を実施することを特徴とする酸性溶液精製用イオン交換樹脂の再生方法。 After contacting the ion exchange resin after purifying the acid solution using the purification method according to any one of claims 1 to 4 with a mineral acid solution, water is added until the TOC of the wash water reaches 30 ppb or less. A method for regenerating an ion-exchange resin for purifying an acidic solution, comprising washing. 前記イオン交換樹脂として、請求項５に記載の再生方法により再生した再生イオン交換樹脂を用いることを特徴とする、請求項１～４のいずれか１項に記載の酸性溶液の精製方法。 The method for purifying an acidic solution according to any one of claims 1 to 4, wherein a regenerated ion exchange resin regenerated by the regenerating method according to claim 5 is used as the ion exchange resin. 対象のイオン交換樹脂に、金属不純物量が１ｍｇ／Ｌ以下でかつ濃度が５重量％以上の鉱酸溶液を接触させて精製することにより精製カチオン交換樹脂を得るイオン交換樹脂精製手段であって、前記精製イオン交換樹脂に、濃度３重量％の塩酸を体積比２５倍量で通過させたときに溶出する全金属不純物溶出量は、５μｇ／ｍＬ―Ｒ以下である、イオン交換樹脂精製手段と、
前記精製イオン交換樹脂を用いて酸性溶液を精製する、酸性溶液精製手段と、
を備えることを特徴とする酸性溶液精製装置。 An ion-exchange resin purifying means for obtaining a purified cation-exchange resin by contacting a target ion-exchange resin with a mineral acid solution having a metal impurity amount of 1 mg/L or less and a concentration of 5% by weight or more, an ion-exchange resin purifying means, wherein the eluted amount of total metal impurities eluted when hydrochloric acid having a concentration of 3% by weight is passed through the purified ion-exchange resin at a volume ratio of 25 times is 5 μg/mL-R or less;
an acidic solution purifying means for purifying an acidic solution using the purified ion exchange resin;
An acidic solution purification device comprising: 酸性溶液の精製後のイオン交換樹脂の再生手段を有する、請求項７に記載の酸溶液精製装置。
8. The acid solution purifier according to claim 7, further comprising means for regenerating the ion exchange resin after purification of the acid solution.
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