JPH0361514B2 - - Google Patents
Info
- Publication number
- JPH0361514B2 JPH0361514B2 JP20702382A JP20702382A JPH0361514B2 JP H0361514 B2 JPH0361514 B2 JP H0361514B2 JP 20702382 A JP20702382 A JP 20702382A JP 20702382 A JP20702382 A JP 20702382A JP H0361514 B2 JPH0361514 B2 JP H0361514B2
- Authority
- JP
- Japan
- Prior art keywords
- gallium
- arsenic
- precipitate
- wastewater
- wastewater containing
- 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
Links
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 claims description 37
- 229910052733 gallium Inorganic materials 0.000 claims description 37
- 229910052785 arsenic Inorganic materials 0.000 claims description 30
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims description 30
- 239000002351 wastewater Substances 0.000 claims description 24
- 239000002244 precipitate Substances 0.000 claims description 20
- 239000003795 chemical substances by application Substances 0.000 claims description 9
- 229960004887 ferric hydroxide Drugs 0.000 claims description 9
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 2
- 238000000975 co-precipitation Methods 0.000 description 7
- 238000011084 recovery Methods 0.000 description 5
- 239000000243 solution Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 229910001447 ferric ion Inorganic materials 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Landscapes
- Removal Of Specific Substances (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
【発明の詳細な説明】
本発明はガリウムおよびヒ素を含む廃水からヒ
素を除去し、ガリウムを回収する廃水の処理法に
関するものである。
近年、電子工業用材料としてヒ化ガリウムの需
要が増大するにつれ、ヒ化ガリウムの製造、加工
工程で排出されるガリウムおよびヒ素を含む廃水
の量が増加して大きな問題になつている。特に、
ヒ素は有害物質であり、環境汚染防止の立場から
排水基準濃度は0.5ppm以下に定められている。
この観点から、ガリウムおよびヒ素を含む廃水の
従来の処理法は廃水中のヒ素濃度を排水基準以下
まで下げることを目的としたものであつた。具体
的には、廃水に可溶性の第二鉄塩を加えて、アル
カリ剤でPHを８〜９に調節し、生成する水酸化第
二鉄の沈澱とヒ素を共沈させ、廃水中のヒ素濃度
を排水基準以下まで下げた後、生成した沈澱のス
ラツジは適当な方法で処理し、廃棄していた。
しかしながら、従来の処理法は有価金属である
ガリウムを回収できない欠点を有している。ガリ
ウムは稀小元素で、その生産には多大のエネルギ
ーが消費される。従つてガリウムを回収すること
は省エネルギー、資源の有効利用の観点からも意
義のあることである。
本発明は、ガリウムおよびヒ素を含有廃水から
環境汚染物質であるヒ素を分離、除去すると同時
に有価金属であるガリウムを分離、回収すること
を目的とする。
本発明はガリウムおよびヒ素を含む廃水に可溶
性第二鉄塩を添加し、アルカリ剤によりPHを調節
してガリウムおよびヒ素を水酸化第二鉄の沈澱と
共沈させ、この沈澱を廃水から分離除去するガリ
ウムおよびヒ素を含む廃水の処理法において該分
離された沈澱を水に懸濁させ、アルカリ剤を添加
してPHをアルカリ側に調節することによりガリウ
ムを沈澱から溶出させ、沈澱を分離させた後、分
離液を蒸発乾固してガリウムを回収する工程を有
することを特徴とするガリウムおよびヒ素を含む
廃水の処理法である。
可溶性第二鉄塩溶液にアルカリ剤を添加する
と、PH２付近から水酸化第二鉄の沈澱が生成し始
める。ヒ素は水酸化第二鉄と共沈して溶液から除
去される。ガリウムは、アルカリ剤の添加により
PH２付近から沈澱し始めるが、PH９付近から沈澱
が再溶解する。従つて、ガリウムおよびヒ素を含
む廃水に可溶性第二鉄塩を加え、アルカリ剤でPH
を２以上、９以下に調節するとガリウムおよびヒ
素は水酸化第二鉄の沈澱と共沈して廃水から分離
除去できる。また、分離された沈澱を水に懸濁さ
せ、アルカリ剤を加えてPHを９以上に調節する
と、ガリウムは再溶解して水酸化第二鉄の沈澱と
分離でき、分離液を濃縮乾固すればガリウムが回
収できる。
以下、本発明について実施例を用いて具体的に
説明する。
表に示すような濃度のガリウム、ヒ素および第
二鉄イオンを含む模擬廃水に、アンモニア水を添
加してPHを５〜８に調節し、ガリウムとヒ素を水
酸化第二鉄の沈澱と共沈させ過により溶液から
分離除去した。共沈時のPHと溶液中のガリウムお
よびヒ素濃度を表に示す。
実施例８において、ヒ素は初濃度が高いために
１回の共沈だけでは0.5ppm以上が残留する。従
つて、ヒ素濃度を環境基準以下にするためには共
沈を繰り返す必要がある。共沈後、別した沈澱
を少量の水に懸濁させ水酸化ナトリウム溶液を添
加してPHを10〜13に調節しガリウムを再溶解さ
せ、その回収率を調べた。表に再溶解時のPHと溶
解中のガリウム濃度およびガリウムの回収率を示
す。
表に示されるように、水酸化第二鉄と共沈させ
ることによりガリウムおよびヒ素は廃水からほと
んど分離除去された。沈澱からの再溶解により50
％以上のガリウムが回収され、共沈時のPHが低い
ほど、また再溶解時のPHが高いほどガリウムの回
収率は高かつた。また本発明の方法を数回繰返す
ことによりさらにガリウムの回収率を高めること
ができる。
本発明のガリウムおよびヒ素を含む廃水の処理
法により廃水からヒ素が分離除去できるだけでな
く、有価金属であるガリウムを高回収率で回収す
ることができた。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wastewater treatment method for removing arsenic from wastewater containing gallium and arsenic and recovering gallium. In recent years, as the demand for gallium arsenide as a material for the electronic industry has increased, the amount of wastewater containing gallium and arsenic discharged from the manufacturing and processing steps of gallium arsenide has increased, which has become a major problem. especially,
Arsenic is a toxic substance, and the standard concentration in wastewater is set at 0.5 ppm or less to prevent environmental pollution.
From this point of view, conventional treatment methods for wastewater containing gallium and arsenic have been aimed at reducing the arsenic concentration in wastewater to below the wastewater standards. Specifically, a soluble ferric salt is added to the wastewater, the pH is adjusted to 8 to 9 with an alkaline agent, and arsenic is co-precipitated with the ferric hydroxide precipitate that is generated, thereby reducing the arsenic concentration in the wastewater. After lowering the water level to below the wastewater standards, the resulting precipitate sludge was treated with an appropriate method and disposed of. However, conventional processing methods have the disadvantage that gallium, which is a valuable metal, cannot be recovered. Gallium is a rare element, and its production consumes a large amount of energy. Therefore, recovering gallium is significant from the viewpoint of energy conservation and effective use of resources. The object of the present invention is to separate and remove arsenic, an environmental pollutant, from wastewater containing gallium and arsenic, and at the same time to separate and recover gallium, a valuable metal. The present invention adds a soluble ferric salt to wastewater containing gallium and arsenic, adjusts the pH with an alkaline agent, co-precipitates gallium and arsenic with precipitated ferric hydroxide, and separates and removes this precipitate from the wastewater. In a method for treating wastewater containing gallium and arsenic, the separated precipitate is suspended in water, and an alkali agent is added to adjust the pH to the alkaline side, thereby eluting gallium from the precipitate and separating the precipitate. This is a method for treating wastewater containing gallium and arsenic, which comprises a step of recovering gallium by evaporating the separated liquid to dryness. When an alkaline agent is added to a soluble ferric salt solution, ferric hydroxide precipitates begin to form around pH 2. Arsenic is removed from solution by coprecipitation with ferric hydroxide. Gallium can be removed by adding an alkali agent.
Precipitation begins at around PH2, but the precipitate begins to dissolve again at around PH9. Therefore, soluble ferric salts are added to wastewater containing gallium and arsenic, and the pH is adjusted with an alkaline agent.
When the value of gallium and arsenic is adjusted to 2 or more and 9 or less, gallium and arsenic can be coprecipitated with the ferric hydroxide precipitate and can be separated and removed from the wastewater. In addition, if the separated precipitate is suspended in water and an alkaline agent is added to adjust the pH to 9 or higher, gallium can be redissolved and separated from the ferric hydroxide precipitate, and the separated liquid can be concentrated to dryness. Garium can be collected. Hereinafter, the present invention will be specifically explained using Examples. Aqueous ammonia was added to simulated wastewater containing gallium, arsenic, and ferric ions at the concentrations shown in the table to adjust the pH to 5 to 8, and gallium and arsenic were co-precipitated with the precipitation of ferric hydroxide. It was separated and removed from the solution by filtration. The table shows the pH during coprecipitation and the gallium and arsenic concentrations in the solution. In Example 8, since the initial concentration of arsenic is high, 0.5 ppm or more remains after just one coprecipitation. Therefore, it is necessary to repeat coprecipitation in order to bring the arsenic concentration below the environmental standard. After coprecipitation, the separated precipitate was suspended in a small amount of water, and a sodium hydroxide solution was added to adjust the pH to 10 to 13 to redissolve gallium, and the recovery rate was examined. The table shows the pH during redissolution, the gallium concentration during dissolution, and the recovery rate of gallium. As shown in the table, most of gallium and arsenic were separated and removed from the wastewater by coprecipitation with ferric hydroxide. 50 by redissolution from precipitate
% or more of gallium was recovered, and the lower the pH at the time of coprecipitation and the higher the pH at the time of redissolution, the higher the recovery rate of gallium. Further, by repeating the method of the present invention several times, the recovery rate of gallium can be further increased. By the method of treating wastewater containing gallium and arsenic of the present invention, not only arsenic could be separated and removed from the wastewater, but also gallium, which is a valuable metal, could be recovered at a high recovery rate. 【table】
Claims (1)
鉄塩を添加し、アルカリ剤によりPHを調節してガ
リウムおよびヒ素を水酸化第二鉄の沈澱と共沈さ
せ、この沈殿を廃水から分離除去するガリウムお
よびヒ素を含む廃水の処理法において該分離され
た沈澱を水に懸濁させ、アルカリ剤を添加してPH
をアルカリ側に調節することによりガリウムを沈
澱から溶出させ、沈澱を分離させた後、分離液を
蒸発乾固してガリウムを回収する工程を有するこ
とを特徴とするガリウムおよびヒ素を含む廃水の
処理法。1 Add soluble ferric salt to wastewater containing gallium and arsenic, adjust the pH with an alkaline agent, co-precipitate gallium and arsenic with precipitate of ferric hydroxide, and separate and remove this precipitate from wastewater. In a method for treating wastewater containing arsenic, the separated precipitate is suspended in water and an alkali agent is added to adjust the pH.
A treatment for wastewater containing gallium and arsenic, comprising the steps of eluting gallium from the precipitate by adjusting to an alkaline side, separating the precipitate, and recovering gallium by evaporating the separated liquid to dryness. Law.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20702382A JPS5995991A (en) | 1982-11-26 | 1982-11-26 | Treatment for waste water containing gallium and arsenic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20702382A JPS5995991A (en) | 1982-11-26 | 1982-11-26 | Treatment for waste water containing gallium and arsenic |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5995991A JPS5995991A (en) | 1984-06-02 |
| JPH0361514B2 true JPH0361514B2 (en) | 1991-09-20 |
Family
ID=16532919
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20702382A Granted JPS5995991A (en) | 1982-11-26 | 1982-11-26 | Treatment for waste water containing gallium and arsenic |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5995991A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62294491A (en) * | 1986-06-11 | 1987-12-21 | Hitachi Plant Eng & Constr Co Ltd | Treatment of waste water incorporating gallium and arsenic |
| JP4072323B2 (en) * | 2001-04-27 | 2008-04-09 | シャープ株式会社 | Method for treating gallium arsenide-containing wastewater and apparatus for treating gallium arsenide-containing wastewater |
| JP2003001275A (en) * | 2001-06-19 | 2003-01-07 | Kurita Water Ind Ltd | Equipment for treatment of waste water containing gallium-arsenic |
| AU2003215913B2 (en) | 2002-01-11 | 2005-09-15 | Lg Electronics Inc. | Washing machine |
-
1982
- 1982-11-26 JP JP20702382A patent/JPS5995991A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5995991A (en) | 1984-06-02 |
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