JPH0679274A - Method for recovering waste slicing water - Google Patents
Method for recovering waste slicing waterInfo
- Publication number
- JPH0679274A JPH0679274A JP23817792A JP23817792A JPH0679274A JP H0679274 A JPH0679274 A JP H0679274A JP 23817792 A JP23817792 A JP 23817792A JP 23817792 A JP23817792 A JP 23817792A JP H0679274 A JPH0679274 A JP H0679274A
- Authority
- JP
- Japan
- Prior art keywords
- water
- slicing
- waste water
- membrane
- waste
- 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.)
- Withdrawn
Links
Landscapes
- Separation Using Semi-Permeable Membranes (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はスライシング排水の回収
方法に関する。更に詳しくは半導体ウェ−ハ−製造工程
のスライシング工程より排出される排水を膜分離装置に
かけ、その濾過水を切削水として再使用するスライシン
グ排水の回収方法の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering slicing waste water. More specifically, the present invention relates to an improvement in a method for collecting slicing wastewater in which the wastewater discharged from the slicing step of the semiconductor wafer manufacturing process is applied to a membrane separation device and the filtered water is reused as cutting water.
【０００２】[0002]
【従来の技術】シリコンウェ−ハ−を製造する工程にス
ライシング工程と称される単結晶インゴットをダイヤモ
ンドブレ−ドで所定の厚さに切断する工程がある。当該
工程ではシリコンインゴットを切断する際に潤滑性を付
与すると同時に発生熱を取り除き、ブレ−ドの寿命を延
ばすため１〜５％の水溶性切削油を含む切削水が用いら
れている。2. Description of the Related Art In the process of manufacturing a silicon wafer, there is a process called a slicing process in which a single crystal ingot is cut to a predetermined thickness with a diamond blade. In this step, cutting water containing 1 to 5% of water-soluble cutting oil is used in order to impart lubricity at the time of cutting the silicon ingot, remove heat generated, and extend the life of the blade.
【０００３】切削排水（以下スライシング排水と記す）
はシリコン微粒子を含む懸濁水であることから、何らか
の処理が必要であるが、前記したように高価な水溶性切
削油を含んでいるため、使い捨てによる経済的損失は非
常に大きく、従来より濾布にケイソウ土をプレコ−トし
たフィルタ−等によりシリコンの微粒子を分離除去し、
繰り返し使用されている。Cutting drainage (hereinafter referred to as slicing drainage)
Since it is suspended water containing silicon fine particles, some treatment is necessary, but as mentioned above, it contains expensive water-soluble cutting oil, so the economic loss due to disposable is very large, and it is more difficult than conventional filter cloths. The particles of diatomaceous earth are pre-coated to separate and remove fine particles of silicon,
Used repeatedly.
【０００４】また、最近では精密濾過膜や限外濾過膜を
用いた膜分離装置による回収方法が提案されている。Recently, a collection method using a membrane separation device using a microfiltration membrane or an ultrafiltration membrane has been proposed.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、濾布に
ケイソウ土をプレコ−トして濾過する方法は０．５ミク
ロン以下のシリコン微粒子がリ−クするため、清澄な濾
過水が得られないという欠点に加え、濾布が目詰まりし
て濾過能力が低下し、濾布の洗浄を手作業で行わなけれ
ばならないという問題がある。However, in the method of precoating diatomaceous earth on a filter cloth and filtering, silicon fine particles of 0.5 micron or less leak, so that clear filtered water cannot be obtained. In addition to the drawbacks, there is a problem that the filter cloth is clogged and the filtering ability is lowered, so that the filter cloth must be washed manually.
【０００６】また、精密濾過膜や限外濾過膜を用いた膜
分離装置により濾過する方法は清澄な濾過水が得られ、
運転管理も容易である等の利点を有するがファウリング
が大きく徐々に濾過能力が低下してしまうため、膜の洗
浄を頻繁に行う必要がある。膜の洗浄は薬品による洗
浄、例えばアルカリ等を使って洗浄が行われるが、その
際には大量に濁った洗浄廃液が発生する。Further, a method of filtering with a membrane separator using a microfiltration membrane or an ultrafiltration membrane gives clear filtered water,
Although it has advantages such as easy operation management, the fouling is large and the filtration capacity gradually decreases, so that it is necessary to wash the membrane frequently. The membrane is washed with a chemical, for example, with an alkali, but in that case, a large amount of turbid washing waste liquid is generated.
【０００７】また、洗浄後は濾過水中に薬品成分がコン
タミするのを防ぐため純水でリンスする必要があるが、
リンス廃水についても排水中に戻すことができないため
洗浄廃液と同様に特別の処理装置または処理手段を必要
とするなどの問題がある。この問題は例えば濾過能力が
低下した時点で膜を取り外して膜分離装置の系の外で洗
浄する場合においても解消することはできない。After washing, it is necessary to rinse with pure water to prevent the chemical components from contaminating the filtered water.
Since the rinse wastewater cannot be returned to the wastewater, there is a problem that a special treatment device or treatment means is required like the cleaning wastewater. This problem cannot be solved even when the membrane is removed and washed outside the system of the membrane separation device, for example, when the filtration capacity is lowered.
【０００８】[0008]
【課題を解決するための手段】これに対して本発明者ら
は精密濾過膜及び限外濾過膜の濾過能力を安定に保つた
めの膜分離装置の運転方法に関し、鋭意検討した結果膜
分離装置に供給するスライシング排水の温度を曇り点以
下に保持することによりファウリングが抑えられ濾過能
力安定性が著しく改善されることを見出し、本発明に到
った。On the other hand, the inventors of the present invention have earnestly studied the method of operating a membrane separation device for maintaining stable filtration performance of a microfiltration membrane and an ultrafiltration membrane, and as a result, the membrane separation device has been investigated. The present invention has been found that by keeping the temperature of the slicing wastewater to be supplied to the cloud point below the cloud point, fouling is suppressed and the stability of the filtration capacity is significantly improved.
【０００９】即ち本発明は、スライシング排水を膜分離
装置にかけ、前記排水中の懸濁物質を分離、除去した濾
過水を回収する方法において、膜分離装置に供給するス
ライシング排水の温度を曇り点以下に保持することを特
徴とするスライシング排水の回収方法である。ここで曇
り点とは界面活性剤が析出して濁りを生じる温度のこと
である。That is, according to the present invention, in a method for collecting slicing wastewater to a membrane separator to recover filtered water from which suspended substances in the wastewater are separated and removed, the temperature of the slicing wastewater supplied to the membrane separator is below a cloud point. It is a method for collecting slicing wastewater, which is characterized in that Here, the cloud point is a temperature at which a surfactant precipitates to cause turbidity.
【００１０】本発明が適用されるスライシング排水は水
溶性切削油、詳しくは合成潤滑剤、無機塩、アミン類と
いった防錆剤、更には界面活性剤、消泡剤等を含み、曇
り点を持つ排水であり、曇り点は通常、水溶性切削油の
濃度が５％以下の低濃度であることから、濃度による変
化はあまりないが可溶化物質の存在により変化する性質
があるので実際に確認することが好ましいが、スライシ
ング排水では濁りがあるため確認がむずかしく、水溶性
切削油を所定の濃度に希釈して確認する必要がある。The slicing wastewater to which the present invention is applied contains a water-soluble cutting oil, specifically, a rust preventive agent such as a synthetic lubricant, an inorganic salt and amines, a surfactant, an antifoaming agent and the like and has a cloud point. It is drainage, and the cloud point is usually a low concentration of water-soluble cutting oil of 5% or less, so it does not change much depending on the concentration, but it actually changes because of the presence of solubilizing substances. However, it is difficult to confirm because the slicing wastewater is turbid, and it is necessary to dilute the water-soluble cutting oil to a predetermined concentration for confirmation.
【００１１】本発明で用いられる膜としては精密濾過
膜、又は限外濾過膜である。膜の材質、構造は特に限定
されないが、一般にスライシング排水のＰＨは８〜９程
度になるので、膜の材質は耐アルカリ性のものが要求さ
れ、膜の孔径は粒子径が０．５ミクロン以下のシリコン
微粒子が存在するため、０．５ミクロン以下、好ましく
は０．２ミクロン以下である。The membrane used in the present invention is a microfiltration membrane or an ultrafiltration membrane. Although the material and structure of the membrane are not particularly limited, since the pH of the slicing wastewater is generally about 8 to 9, the material of the membrane is required to be alkali resistant, and the pore diameter of the membrane is 0.5 micron or less. Due to the presence of silicon fine particles, it is 0.5 micron or less, preferably 0.2 micron or less.
【００１２】また、膜分離装置に供給するスライシング
排水の温度はスライシング排水の貯槽に冷却器を設置す
るか、または膜分離装置の供給配管の途中に熱交換器を
設けてコントロ−ルされるが、逆洗機構を備えた膜分離
装置にあっては、通常の場合、切削水中の水溶性切削油
の濃度を一定に保つ必要があるため、逆洗水として濾過
水が使用されるので、逆洗による膜の目詰まりを防ぐた
め、逆洗水の温度も曇り点以下に保つことが重要であ
る。The temperature of the slicing wastewater supplied to the membrane separator is controlled by installing a cooler in the storage tank of the slicing wastewater or by providing a heat exchanger in the supply pipe of the membrane separator. In a membrane separator equipped with a backwashing mechanism, it is usually necessary to keep the concentration of water-soluble cutting oil in the cutting water constant, so filtered water is used as backwashing water. It is important to keep the temperature of the backwash water below the cloud point in order to prevent clogging of the membrane due to washing.
【００１３】また、膜分離装置の運転方式は濾過能力を
安定に保つためクロスフロ−方式（循環濾過方式）であ
る必要があり、循環時の線速は０．５〜３ｍ／秒、好ま
しくは１．５〜２．５ｍ／秒である。Further, the operation system of the membrane separation device must be a cross flow system (circulation filtration system) in order to keep the filtration capacity stable, and the linear velocity during circulation is 0.5 to 3 m / sec, preferably 1 0.5 to 2.5 m / sec.
【００１４】[0014]
【実施例】以下に本発明の実施例及び比較例を挙げる
が、本発明はこれに限定されるものではない。EXAMPLES Examples and comparative examples of the present invention will be given below, but the present invention is not limited thereto.
【００１５】[0015]
【実施例１】中空糸状のポリアクリロニトリル限外濾過
膜（旭化成工業株式会社製、分画分子量１３０００）を
装着した膜分離装置を用いて、表１に示す平均性状のス
ライシング排水を入口圧力１．５Ｋｇ／ｃｍ2 、出口圧
力０．５Ｋｇ／ｃｍ2 、線速２．２ｍ／秒、温度２１〜
２２℃の条件下で濃縮倍率１０倍（切削水回収率９０
％）となるように処理した。なお、水溶性切削油を所定
の濃度（３％）に希釈して測定した場合の曇り点は２５
℃であった。Example 1 Using a membrane separator equipped with a hollow fiber polyacrylonitrile ultrafiltration membrane (manufactured by Asahi Kasei Kogyo Co., Ltd., molecular weight cutoff 13000), the slicing wastewater having the average properties shown in Table 1 was introduced at an inlet pressure of 1. 5 Kg / cm 2 , outlet pressure 0.5 Kg / cm 2 , linear velocity 2.2 m / sec, temperature 21-
Concentration factor 10 times (Cutting water recovery rate 90
%). The cloud point is 25 when measured by diluting the water-soluble cutting oil to a predetermined concentration (3%).
It was ℃.
【００１６】膜分離装置の運転は３０分経過する毎、限
外濾過膜に流す方向を交互に変えながら（入口、出口を
逆にして）濾過を行なった後、濾過水を使って１．０ｋ
ｇ／ｃｍ2 の圧力で３０秒間逆洗することの繰り返しで
行なった。濾過能力は初期９２リットル／ｍ2 Ｈｒ、１
ケ月後で７３リットル／ｍ2 Ｈｒであった。そして、こ
の間の濾過水の平均的性状は表１の通りであった。Every 30 minutes, the membrane separator is operated while performing filtration while alternately changing the direction of flow through the ultrafiltration membrane (reversing the inlet and the outlet), and then using 1.0 k of filtered water.
This was repeated by backwashing for 30 seconds at a pressure of g / cm 2 . Initial filtration capacity is 92 liters / m 2 Hr, 1
It was 73 liters / m 2 Hr after a month. The average properties of the filtered water during this period are shown in Table 1.
【００１７】[0017]
【比較例１】膜分離装置を２８〜３０℃で運転した以
外、実施例１と同様の方法で１ケ月間運転した後の濾過
能力は運転初期９５リットル／ｍ2 Ｈｒに対して３７リ
ットル／ｍ2 Ｈｒであり、約６０％の低下があった。こ
の間の濾過水の平均的性状を表１に示す。Comparative Example 1 The filtration capacity after operating for 1 month in the same manner as in Example 1 except that the membrane separator was operated at 28 to 30 ° C. was 37 liter / m 2 Hr / 95 liter / m 2 Hr at the beginning of the operation. m 2 Hr, which was a decrease of about 60%. Table 1 shows the average properties of the filtered water during this period.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【発明の効果】本発明は膜分離装置にかけるスライシン
グ排水の温度を曇り点以下に保つことにより、有効成分
の回収率を低下させることなく、少ない洗浄回数で膜分
離装置の濾過能力を維持することができ、効率的かつ経
済的である。Industrial Applicability According to the present invention, the temperature of the slicing waste water applied to the membrane separation device is kept below the cloud point to maintain the filtration capacity of the membrane separation device with a small number of washings without lowering the recovery rate of the active ingredient. Can be, efficient and economical.
Claims (1)
前記排水中の懸濁物質を分離、除去した濾過水を回収す
る方法において、膜分離装置に供給する排水の温度を曇
り点以下に保持することを特徴とするスライシング排水
の回収方法。1. A slicing wastewater is applied to a membrane separation device,
A method for recovering slicing wastewater, characterized in that the temperature of the wastewater supplied to the membrane separation device is maintained at a cloud point or lower in the method for collecting filtered water from which suspended substances in the wastewater are separated and removed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23817792A JPH0679274A (en) | 1992-09-07 | 1992-09-07 | Method for recovering waste slicing water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23817792A JPH0679274A (en) | 1992-09-07 | 1992-09-07 | Method for recovering waste slicing water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0679274A true JPH0679274A (en) | 1994-03-22 |
Family
ID=17026323
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23817792A Withdrawn JPH0679274A (en) | 1992-09-07 | 1992-09-07 | Method for recovering waste slicing water |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0679274A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002040407A1 (en) * | 2000-11-17 | 2002-05-23 | Metallkraft As | Method for utilising a waste slurry from silicon wafer production |
-
1992
- 1992-09-07 JP JP23817792A patent/JPH0679274A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002040407A1 (en) * | 2000-11-17 | 2002-05-23 | Metallkraft As | Method for utilising a waste slurry from silicon wafer production |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19991130 |