JP4096433B2 - Removal of nickel from caustic potash - Google Patents
Removal of nickel from caustic potash Download PDFInfo
- Publication number
- JP4096433B2 JP4096433B2 JP37278798A JP37278798A JP4096433B2 JP 4096433 B2 JP4096433 B2 JP 4096433B2 JP 37278798 A JP37278798 A JP 37278798A JP 37278798 A JP37278798 A JP 37278798A JP 4096433 B2 JP4096433 B2 JP 4096433B2
- Authority
- JP
- Japan
- Prior art keywords
- nickel
- caustic potash
- activated carbon
- caustic
- ppm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Treatment Of Liquids With Adsorbents In General (AREA)
- Removal Of Specific Substances (AREA)
- Filtration Of Liquid (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Description
【０００１】
【発明の属する技術分野】
この発明は、工業的に製造される苛性カリ中のニッケルを効果的に除去することができる苛性カリ中のニッケルの除去方法に関するものである。
【０００２】
【従来の技術】
たとえば、半導体ウェーハなどの電子部品の製造においては、ウェーハの表面をエッチングして平面化し、あるいは表面を洗浄するために苛性アルカリが使用されている。
【０００３】
かゝる電子部品の洗浄に使用される苛性アルカリは、半導体ウェーハの劣化、半導体デバイスの特性の低下などを防ぐため、ニッケル、クロム、鉄、銅などの金属不純物を含まない高純度の苛性アルカリを水溶液として用いることが要求されているので、たとえば、特開昭６３−８２１５号公報では、イオン交換膜法で得られた苛性ソーダ中のクロムとニッケルを吸着共沈によって同時に除去する金属不純物の除去方法を提案している。
【０００４】
特開平１０−３１０８８３号公報においては、アルカリ水溶液中に存在している金属イオンの可逆電位より卑な酸化電位を持つ還元剤、たとえば、亜二チオン酸塩などを溶解して不純な金属イオンを非イオン化してアルカリ溶液を純化する手段を開示している。
【０００５】
【発明が解決しようとする課題】
前記の電子部品等の製造に際して使用される高純度の苛性アルカリのうち、苛性カリの需要はかなり高く、かゝる高純度苛性カリは他にも工業用試薬や医薬品関連に用いられている。
この電子部品等の製造に際して用いられる苛性カリ水溶液は、その中に含まれる不純金属としてのニッケルが、アルカリエッチングにおいて半導体ウェーハの内部に拡散してウェーハを劣化させるため、これを除去する要望が特に強い。
【０００６】
かゝるニッケルは、電解等で得た苛性カリを高濃度に濃縮する際に、ニッケルを含むステンレス鋼を材質とした濃縮装置を使用した場合に僅かではあるが溶出する。
本来、このニッケルは苛性アルカリに耐性のある金属素材であるので、苛性カリの一般販売濃度である４８．５％程度、高々５０％までの濃縮で０．１ｐｐｍのオーダーのニッケルの溶出量に留まっているが、濃縮温度を高めるとニッケルの溶出量は多くなってくる。
【０００７】
前記特開昭６３−８２１５号公報や特開平１０−３１０８８３号公報に開示されている金属不純物の除去は、いずれも実質的に苛性ソーダを対象にしているものゝ、苛性カリの高純度化についてなんら具体的な開示はない。
【０００８】
一方、特開昭６３−８３１５号公報においては、金属不純物としてのニッケルとクロムを、０．１ｐｐｍ程度のオーダーにまで低下させること開示しており、ニッケルと共にクロムの存在を必要な条件としているものであって、ニッケルのみを除去するものではなく、特開平１０−３１０８８３号公報では、前記の還元剤によって金属イオンを非イオン化してニッケル濃度が１０ｐｐｂ（０．０１ｐｐｍ）程度のかなりの低い値に純化している。
【０００９】
しかしながら、この純化の方法は不純な金属イオンを非イオンとして還元しているのみで、これをアルカリ溶液から積極的に除去するものではなく、この非イオン化不純物が固体として存在していても金属イオンとして存在しなければ純化された状態にあるとして液中に存在することを許容しているものである。
したがって、この純化したとされるアルカリ水溶液が前記半導体ウェーハの製造に適用できるとしても、工業用試薬や医薬品関連用などの他の用途に使用するにはなんらかの手段でこの還元析出物を除去する必要がある。
【００１０】
この発明はかゝる問題点に鑑み、苛性カリの濃縮などで溶出してくる０．１ｐｐｍのオーダーのニッケルをきわめて簡単な手段でより効率的に除去して０．０１ｐｐｍ程度のオーダーまで低下させることによって、電子部品関係はもとより他の高純度苛性カリの用途にも支障なく使用することができるニッケル含有量の少ない苛性カリを得んとするものである。
【００１１】
【課題を解決するための手段】
前記の目的を達成するため、この発明の苛性カリ中のニッケルの除去方法は、活性炭をプレコートした濾過装置を用いた濾過操作により苛性カリ水溶液中に存在するニッケルを０．１ｐｐｍオーダーから０．０１ｐｐｍオーダーである０．０５ｐｐｍ以下に減少させることを特徴とするものである。
【００１２】
【発明の実施の形態】
この発明の苛性カリ中のニッケルの除去方法は、活性炭をプレコート剤とした濾過装置によってニッケルを含む苛性カリ水溶液を濾過するものであるが、プレコート剤としての活性炭は、ヤシ殻、木材、木炭、亜炭などを炭化処理して得られる吸着能の大きな多孔性炭素を使用することができ、それらの中でもヤシ殻活性炭がニッケルの吸着能に優れているので最も好ましい。
【００１３】
使用する濾過装置は、活性炭をプレコートした濾過装置であればよく、特に制限はない。
【００１４】
前記ニッケルを含む苛性カリの濃度、活性炭の使用量、濾過装置への通液流速や通液量などについても特別な制限はないが、たとえば、濃度約５０％の苛性カリ水溶液中に約０．１ｐｐｍのオーダーで含まれているニッケルの除去には、濾過装置の濾過面積に対して１００〜２０００ｇ／ｍ2 の範囲の量のヤシ殻活性炭を使用することが好ましい。
【００１５】
【作用】
この発明の苛性カリ中のニッケルの除去方法は、活性炭、特に、ヤシ殻活性炭をプレコート剤として用いた濾過装置にニッケルを不純物として含む苛性カリ水溶液を通液することによって、優れた濾過性能を発揮して短時間に苛性カリ水溶液中のニッケルを除去することができ、電子部品等の製造やその他の純度の高い苛性カリを要求する用途に適用し得る高純度苛性カリを容易に得ることができるものである。
【００１６】
【実施例】
以下、実施例によってこの発明の苛性カリ中のニッケルの除去方法をより具体的に説明する。
＜実施例１＞
ニッケルを含有した濃度４８％の苛性カリ水溶液を、濾過装置を使用して下記の条件下で苛性カリ中のニッケルを除去した。
濾過装置 ； 三進濾過器（濾過面積３ｍ2 ）（三進製作所製）
活性炭 ； 「花Ｂ」ドライ （セラケム（株）製のヤシ殻活性炭）
活性炭使用量； ５００ｇ／ｍ2
通液速度 ； ５００ｌ／ｈ（０．１７ｍ／ｈ）
通液量 ； ２０００ｍ3
上記の条件下で、前記三進濾過器の入口と出口の苛性カリ中のニッケル含有量（単位；ｐｐｍ）を測定し、下記〔表１〕の結果を得た。
【００１７】
【表１】
【００１８】
この〔表１〕から明らかなように、苛性カリ水溶液中のニッケルが濾過器の入口で０．１ｐｐｍのオーダーであったものが、濾過器の出口においては、これより１桁低い０．０１ｐｐｍのオーダーである０．０５ｐｐｍ以下に下げることができたもので、通液によってきわめて優れたニッケル除去が達成されていることが判る。
【００１９】
【発明の効果】
この発明の苛性カリ中のニッケル除去方法は、活性炭、特にヤシ殻活性炭をプレコート剤として用いた濾過装置に、ニッケルを不純物として含む苛性カリ水溶液を通液することにより、優れた濾過性能を発揮して短時間に苛性カリ中のニッケルを取り除くことができる。
【００２０】
特に、この発明の苛性カリ中のニッケル除去方法は、簡単な処理手段と安価な費用によって苛性カリ水溶液中のニッケルを低レベルまで除去し、電子部品等の製造やその他の用途に充分に使用できる純度の高い苛性カリが容易に得られる点で優れたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing nickel in caustic potash that can effectively remove nickel in caustic potash produced industrially.
[0002]
[Prior art]
For example, in the manufacture of electronic components such as semiconductor wafers, caustic is used to etch and planarize the surface of the wafer or to clean the surface.
[0003]
Caustic alkali used for cleaning such electronic components is a high-purity caustic alkali that does not contain metallic impurities such as nickel, chromium, iron, and copper to prevent deterioration of semiconductor wafers and semiconductor device characteristics. Is required to be used as an aqueous solution. For example, in Japanese Patent Application Laid-Open No. 63-8215, removal of metal impurities by simultaneously removing chromium and nickel in caustic soda obtained by an ion exchange membrane method by adsorption coprecipitation Proposed method.
[0004]
In Japanese Patent Application Laid-Open No. 10-310883, an impure metal ion is dissolved by dissolving a reducing agent having a base oxidation potential lower than the reversible potential of a metal ion present in an alkaline aqueous solution, such as dithionite. A means for deionizing and purifying an alkaline solution is disclosed.
[0005]
[Problems to be solved by the invention]
Among the high-purity caustic alkalis used in the production of the electronic parts and the like, the demand for caustic potash is quite high, and such high-purity caustic potash is used for industrial reagents and pharmaceuticals.
In the caustic potash aqueous solution used in the manufacture of electronic parts and the like, nickel as an impure metal contained therein is diffused into the semiconductor wafer by alkali etching to deteriorate the wafer. .
[0006]
Such nickel elutes, though slightly, when a concentration device made of stainless steel containing nickel is used when caustic potash obtained by electrolysis or the like is concentrated to a high concentration.
Originally, this nickel is a metal material that is resistant to caustic, so the concentration of caustic potash is about 48.5%, and the concentration of nickel up to 50% is only about 0.1ppm. However, the elution amount of nickel increases with increasing concentration temperature.
[0007]
The removal of metal impurities disclosed in JP-A-63-8215 and JP-A-10-310883 is practically intended for caustic soda, and there is nothing specific about increasing the purity of caustic potash. There is no formal disclosure.
[0008]
On the other hand, JP-A-63-8315 discloses that nickel and chromium as metal impurities are reduced to the order of about 0.1 ppm, and the presence of chromium together with nickel is a necessary condition. However, it does not remove only nickel. In Japanese Patent Laid-Open No. 10-310883, the metal ions are deionized by the reducing agent, and the nickel concentration is reduced to a considerably low value of about 10 ppb (0.01 ppm). Purified.
[0009]
However, this purification method only reduces the impure metal ions as non-ions and does not actively remove them from the alkaline solution. Even if these non-ionized impurities exist as solids, the metal ions If it does not exist, it is allowed to exist in the liquid as being in a purified state.
Therefore, even if this purified alkaline aqueous solution can be applied to the production of the semiconductor wafer, it is necessary to remove this reduced precipitate by some means for use in other applications such as industrial reagents and pharmaceuticals. There is.
[0010]
In view of such problems, the present invention removes nickel in the order of 0.1 ppm eluted by caustic potash concentration and the like more efficiently and lowers it to the order of about 0.01 ppm. Therefore, it is intended to obtain caustic potash with a low nickel content that can be used without problems for electronic parts and other uses of high purity caustic potash.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the method for removing nickel in caustic potash according to the present invention is characterized in that the nickel present in the caustic potash aqueous solution is filtered from a 0.1 ppm order to an 0.01 ppm order by using a filtration device pre-coated with activated carbon. It is characterized by being reduced to a certain 0.05 ppm or less .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The method for removing nickel in caustic potash of the present invention is to filter a caustic potash aqueous solution containing nickel by a filtering device using activated carbon as a precoat agent. The activated carbon as a precoat agent is coconut shell, wood, charcoal, lignite, etc. Porous carbon having a large adsorptive capacity obtained by carbonizing can be used, and among these, coconut shell activated carbon is most preferable because it has an excellent ability to adsorb nickel.
[0013]
The filtration device to be used is not particularly limited as long as it is a filtration device pre-coated with activated carbon.
[0014]
There are no particular restrictions on the concentration of caustic potash containing nickel, the amount of activated carbon used, the flow rate or the flow rate of liquid through the filtration device. For example, about 0.1 ppm of caustic potash aqueous solution having a concentration of about 50%. For removing nickel contained in the order, it is preferable to use coconut shell activated carbon in an amount in the range of 100 to 2000 g / m 2 with respect to the filtration area of the filtration device.
[0015]
[Action]
The method for removing nickel in caustic potash of the present invention exhibits excellent filtration performance by passing a caustic potash aqueous solution containing nickel as an impurity through a filter using activated carbon, in particular, coconut shell activated carbon as a precoat agent. Nickel in an aqueous caustic potash solution can be removed in a short time, and high-purity caustic potash can be easily obtained that can be applied to the manufacture of electronic components and other uses that require high-purity caustic potash.
[0016]
【Example】
Hereinafter, the method for removing nickel in caustic potash of the present invention will be described more specifically with reference to examples.
<Example 1>
The nickel in caustic potash was removed from the 48% concentration caustic potash aqueous solution containing nickel under the following conditions using a filter.
Filtration device; Sanshin filter (filtration area 3m 2 ) (manufactured by Sanshin Seisakusho)
Activated carbon ： “Hana B” dry (coconut shell activated carbon manufactured by Serakhem Co., Ltd.)
Activated carbon consumption: 500 g / m 2
Flow rate: 500 l / h (0.17 m / h)
Through volume: 2000m 3
Under the above conditions, the nickel content (unit: ppm) in the caustic potash at the inlet and outlet of the ternary filter was measured, and the results shown in Table 1 below were obtained.
[0017]
[Table 1]
[0018]
As is clear from this [Table 1], the nickel in the caustic potash aqueous solution was on the order of 0.1 ppm at the inlet of the filter, but at the outlet of the filter, it was on the order of 0.01 ppm, which is one digit lower than this. It can be seen that the nickel removal can be reduced to 0.05 ppm or less .
[0019]
【The invention's effect】
The method for removing nickel in caustic potash according to the present invention exhibits excellent filtration performance and is short by passing a caustic potash aqueous solution containing nickel as an impurity through a filtering device using activated carbon, particularly coconut shell activated carbon, as a precoat agent. The nickel in caustic potash can be removed in time.
[0020]
In particular, the method for removing nickel in caustic potash according to the present invention removes nickel in a caustic potash aqueous solution to a low level by simple processing means and low cost, and has a purity sufficient for use in the manufacture of electronic components and other applications. It is excellent in that high caustic potash can be easily obtained.
Claims (2)
を特徴とする苛性カリ中のニッケルの除去方法。A method for removing nickel in caustic potash, characterized in that nickel present on the order of 0.1 ppm in a caustic potash aqueous solution is reduced to 0.05 ppm or less by a filtering operation using a filter pre-coated with activated carbon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP37278798A JP4096433B2 (en) | 1998-12-28 | 1998-12-28 | Removal of nickel from caustic potash |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP37278798A JP4096433B2 (en) | 1998-12-28 | 1998-12-28 | Removal of nickel from caustic potash |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000203828A JP2000203828A (en) | 2000-07-25 |
| JP4096433B2 true JP4096433B2 (en) | 2008-06-04 |
Family
ID=18501047
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP37278798A Expired - Lifetime JP4096433B2 (en) | 1998-12-28 | 1998-12-28 | Removal of nickel from caustic potash |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4096433B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI306837B (en) * | 2004-08-06 | 2009-03-01 | Asahi Kasei Chemicals Corp | Method for purifying aqueous alkaline solution |
| JP2007045678A (en) * | 2005-08-11 | 2007-02-22 | Toagosei Co Ltd | Vessel useful for producing high purity potassium hydroxide |
| JP5125509B2 (en) * | 2005-08-11 | 2013-01-23 | 東亞合成株式会社 | Manufacturing method of high purity caustic potash |
| JP5049528B2 (en) * | 2006-07-31 | 2012-10-17 | 東亞合成株式会社 | Method for producing high purity alkali metal hydroxide |
| RU2446102C1 (en) * | 2010-11-01 | 2012-03-27 | Российская Федерация, От Имени Которой Выступает Министерство Образования И Науки Российской Федерации | Method of purifying potassium hydroxide solution |
-
1998
- 1998-12-28 JP JP37278798A patent/JP4096433B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000203828A (en) | 2000-07-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5122274A (en) | Method of treating fluids | |
| US4642192A (en) | Method of treating fluids | |
| US5149437A (en) | Water filter | |
| US5269932A (en) | Method of treating fluids | |
| KR101167354B1 (en) | Method of purifying aqueous alkali solution | |
| JP4096433B2 (en) | Removal of nickel from caustic potash | |
| JP2004515431A (en) | Method for removing mercury from gas | |
| EP0185031B1 (en) | Method of treating fluids | |
| US4744825A (en) | Removal and recovery of silver from waste stream | |
| JP2007505736A5 (en) | ||
| UA80456C2 (en) | Method for removing mercury from solutions contaminated with mercury | |
| JP4297663B2 (en) | Boron recovery method | |
| JPH11235595A (en) | Treatment of boron-containing waste water | |
| JP4996172B2 (en) | Method for producing high purity alkali metal hydroxide | |
| JPH0478438A (en) | Activated alumina for removing heavy metal and production of silver nitrate using the same | |
| JP4013646B2 (en) | Anion exchange resin, method for producing the same, and method for producing purified hydrogen peroxide water using the same | |
| JPH0683789B2 (en) | Sulfate ion removal method with inorganic ion exchanger | |
| JP2008050197A (en) | Method for producing high-purity alkali metal hydroxide | |
| JP3992996B2 (en) | Wastewater treatment method and apparatus | |
| JP4116163B2 (en) | Purification method | |
| JP2500568B2 (en) | Method for purifying chemical solution containing hydrofluoric acid | |
| JP4505952B2 (en) | Manufacturing method of high purity ferric chloride aqueous solution | |
| JP2691016B2 (en) | How to regenerate iron liquid | |
| JP4393616B2 (en) | Boron fixing agent and treatment method of boron-containing waste water | |
| JP4872097B2 (en) | Purification method of gallium-containing solution |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050204 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070731 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20071023 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20071225 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20080219 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20080303 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110321 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110321 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110321 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120321 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120321 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130321 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130321 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140321 Year of fee payment: 6 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| EXPY | Cancellation because of completion of term |