JP2813551B2 - Extraction and separation of metal elements using supercritical fluid as medium - Google Patents
Extraction and separation of metal elements using supercritical fluid as mediumInfo
- Publication number
- JP2813551B2 JP2813551B2 JP21719494A JP21719494A JP2813551B2 JP 2813551 B2 JP2813551 B2 JP 2813551B2 JP 21719494 A JP21719494 A JP 21719494A JP 21719494 A JP21719494 A JP 21719494A JP 2813551 B2 JP2813551 B2 JP 2813551B2
- Authority
- JP
- Japan
- Prior art keywords
- extraction
- medium
- supercritical fluid
- liquid
- nitric acid
- 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 - Fee Related
Links
Classifications
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は原子力発電炉の使用済み
核燃料を溶解した硝酸溶液中からの、あるいは使用済み
燃料の湿式再処理工程で生じる高レベル廃液中からの金
属元素の抽出分離、回収方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the extraction and separation of metal elements from a nitric acid solution in which spent nuclear fuel is dissolved in a nuclear power reactor or from a high-level waste liquid generated in a wet reprocessing step of spent fuel. It is about the method.
【０００２】[0002]
【従来の技術】従来使用済み核燃料を溶解した硝酸溶液
中からの、あるいは使用済み燃料の湿式再処理工程で生
じる高レベル放射性硝酸溶液中からの金属元素の抽出分
離法として、液／液分配抽出法が広く用いられている。
液／液分配抽出法は、水溶液とお互いに溶解し合わず液
／液界面を有する二相系を形成する有機溶媒を抽出媒体
とし、これに金属イオンと疎水性の高い金属錯体を形成
する有機錯体形成試薬を溶存させ、これら二相を混合す
ることによって水溶液から金属イオンを抽出媒体へ抽
出、分離する方法である。2. Description of the Related Art As a method for extracting and separating metal elements from a nitric acid solution in which spent nuclear fuel is dissolved or from a high-level radioactive nitric acid solution generated in a wet reprocessing process of spent fuel, a liquid / liquid partition extraction method is used. The law is widely used.
The liquid / liquid distribution extraction method uses an organic solvent which does not dissolve in an aqueous solution and forms a two-phase system having a liquid / liquid interface as an extraction medium, and an organic solvent which forms a highly hydrophobic metal complex with a metal ion. This is a method of extracting and separating metal ions from an aqueous solution into an extraction medium by dissolving a complex forming reagent and mixing these two phases.
【０００３】この液／液分配抽出法では有機溶媒として
ケロシンやドデカンなどが使用され、有機抽出剤として
燐含有中性有機試薬であるリン酸トリ−ｎ−ブチルやカ
ルバモイルメチルホスフィンオキサイドなどが使用され
る。有機溶媒に抽出された金属元素は、逆抽出条件下で
別組成の水溶液中に逆抽出され、回収される。金属を取
り除いた後の有機溶媒は、精製工程を経た後再利用され
るか、低レベル放射性有機廃液として処理される。In this liquid / liquid distributed extraction method, kerosene or dodecane is used as an organic solvent, and a phosphorus-containing neutral organic reagent such as tri-n-butyl phosphate or carbamoylmethylphosphine oxide is used as an organic extractant. You. The metal element extracted into the organic solvent is back-extracted into an aqueous solution having a different composition under the back-extraction conditions and is recovered. The organic solvent after removing the metal is reused after a purification step, or is treated as a low-level radioactive organic waste liquid.
【０００４】[0004]
【発明が解決しようとする課題】液／液分配抽出法で用
いる有機溶媒は、人体に有害であるものも多く、可燃性
であり、また、強い放射線によって分解、劣化する。こ
のため、使用済み核燃料の硝酸溶液等を対象とする分
離、回収プロセスには厳しい安全対策が必要であると同
時に、有機溶媒の劣化等に伴い低レベル放射性有機廃液
が大量に生じる。また有機溶媒を再利用する場合にも精
製工程を経る必要がある。本発明はこのような問題点を
持つ有機溶媒を全く使用しない新しい抽出法に関するも
のである。Many of the organic solvents used in the liquid / liquid distribution extraction method are harmful to the human body, are flammable, and are decomposed and deteriorated by strong radiation. For this reason, strict safety measures are required for the separation and recovery process for the nitric acid solution and the like of spent nuclear fuel, and at the same time, a large amount of low-level radioactive organic waste liquid is generated due to deterioration of the organic solvent and the like. Also, when an organic solvent is reused, it is necessary to go through a purification step. The present invention relates to a new extraction method which does not use any organic solvent having such a problem.
【０００５】[0005]
【課題を解決するための手段】本発明は、従来使用済み
核燃料からの金属元素の分離、回収に用いられてきた液
／液分配抽出法から生ずる低レベル放射性有機廃液の量
を低減すること、作業上の安全性を高めることを目的と
している。そのため本発明は従来用いられてきた有機溶
媒の代わりに二酸化炭素、窒素などの無機物の気体の超
臨界流体を用い、リン酸トリ−ｎ−ブチル等の中性有機
試薬を抽出剤として硝酸酸性溶液中からの金属元素の抽
出、分離を可能とするものである。SUMMARY OF THE INVENTION The present invention is to reduce the amount of low level radioactive organic waste resulting from liquid / liquid distributed extraction methods conventionally used for the separation and recovery of metallic elements from spent nuclear fuel; The purpose is to increase work safety. Therefore, the present invention uses a supercritical fluid of an inorganic gas such as carbon dioxide and nitrogen in place of the conventionally used organic solvent, and a nitric acid solution using a neutral organic reagent such as tri-n-butyl phosphate as an extracting agent. It enables extraction and separation of metal elements from inside.
【０００６】即ち、前述のとおり、従来使用済み核燃料
を溶解した硝酸溶液中からの、あるいは使用済み燃料の
湿式再処理工程で生じる高レベル放射性硝酸溶液中から
の金属元素の抽出分離法として広く用いられている液／
液分配抽出法では、大量の有機溶媒を抽出媒体として用
いるため大量の低レベル放射性有機廃液が生じるととも
に、有機溶媒の毒性や可燃性から操作上の安全性に留意
する必要があったが、本発明では二酸化炭素等の常温、
常圧下で気体である無機物の超臨界流体を抽出媒体と
し、中性有機試薬を抽出剤として用いる金属元素の新し
い抽出法を発明した。That is, as described above, the conventional method is widely used for extracting and separating metal elements from a nitric acid solution in which spent nuclear fuel is dissolved or from a high-level radioactive nitric acid solution generated in a wet reprocessing step of spent fuel. Liquid /
In the liquid extraction method, a large amount of organic solvent is used as the extraction medium, so that a large amount of low-level radioactive organic waste liquid is generated, and it is necessary to pay attention to the operational safety due to the toxicity and flammability of the organic solvent. In the invention, normal temperature such as carbon dioxide,
We have invented a new method for extracting metal elements using an inorganic supercritical fluid, which is a gas at normal pressure, as an extraction medium and a neutral organic reagent as an extractant.
【０００７】そこで、本発明の特徴は、通常抽出媒体と
して用いることのできない気体状の無機物を超臨界状態
に保ち、物質の溶解性を向上させることにより抽出媒体
として使用可能としたことである。このことにより、低
レベル放射性有機廃液の減量化、作業上の安全性の向上
が達成できた。またこの抽出媒体は超臨界状態より気体
に変換することにより容易に金属元素、抽出剤から分離
でき、回収、再利用することができる。この抽出法にお
いては、二酸化炭素、一酸化炭素、アンモニア、六フッ
化硫黄、窒素などの無機物の気体の超臨界流体を抽出剤
として用い、又リン酸トリ−ｎ−ブチル、トリフェニル
フォスフィンオキサイド（ＴＯＰＯ）、カルバモイルメ
チルフォスフィンオキサイド（ＣＭＰＯ）等の中性有機
試薬を抽出剤として用いた本発明の実施例においては、
有機溶媒を抽出媒体として用いる従来の抽出法より希土
類元素の高い抽出率を得ることができた。Therefore, a feature of the present invention is that a gaseous inorganic substance which cannot be used as an extraction medium can be used as an extraction medium by maintaining a supercritical state and improving the solubility of the substance. As a result, a reduction in the amount of low-level radioactive organic waste liquid and an improvement in operational safety were achieved. The extraction medium can be easily separated from the metal element and the extractant by converting it from a supercritical state to a gas, and can be recovered and reused. In this extraction method, a supercritical fluid of an inorganic gas such as carbon dioxide, carbon monoxide, ammonia, sulfur hexafluoride, and nitrogen is used as an extracting agent, and tri-n-butyl phosphate and triphenylphosphine oxide are used. In an embodiment of the present invention using a neutral organic reagent such as (TOPO) or carbamoylmethylphosphine oxide (CMPO) as an extractant,
It was possible to obtain a higher extraction rate of rare earth elements than the conventional extraction method using an organic solvent as an extraction medium.
【０００８】超臨界状態とは個々の化合物に固有の物理
量である臨界温度と臨界圧力以上の温度、圧力下にある
物質の状態を言い、この状態下にある物質を超臨界流体
と称する。超臨界流体の種々の物理量はその化合物の気
体と液体状態での物理量の間の値を取る。例えば超臨界
流体の密度は気体状態の密度より大きく、すなわち物質
を溶解する能力が気体のときよりも高い。従って常温、
常圧下では気体であり、抽出媒体として利用することが
できない化合物でも、超臨界状態に保つことにより金属
錯体を溶解する能力を高めることができ、媒体として利
用できる。[0008] The supercritical state refers to a state of a substance under a temperature and pressure equal to or higher than a critical temperature and a critical pressure, which are physical quantities specific to individual compounds, and a substance under this state is referred to as a supercritical fluid. Various physical quantities of the supercritical fluid take values between the physical quantities of the compound in the gas and liquid states. For example, the density of a supercritical fluid is greater than that of a gaseous state, that is, the ability to dissolve a substance is higher than that of a gas. Therefore at room temperature,
Compounds that are gaseous at normal pressure and cannot be used as an extraction medium can be used as a medium because the ability to dissolve a metal complex can be enhanced by maintaining the compound in a supercritical state.
【０００９】また超臨界流体中での物質の拡散速度は液
体状態中でのそれより早く、その結果超臨界流体を媒体
とする抽出速度は早いことが期待できる。例えば二酸化
炭素は臨界温度が 31.3 ℃、臨界圧力が 72.9 atm と臨
界条件が容易に達成でき、また無毒で安価であるという
利点を持つため、抽出媒体として用いるのに最も適して
いる。この二酸化炭素は常温、常圧下では気体であるた
め、金属元素を抽出した後の超臨界二酸化炭素を常温、
常圧に戻すことにより気化させ、この媒体を容易に抽出
物から完全に分離することができ、媒体に含まれていた
金属元素を酸溶液中に回収できる。また気化して回収し
た媒体は精製することなく再利用することができる。The diffusion rate of a substance in a supercritical fluid is faster than that in a liquid state. As a result, it can be expected that the extraction rate using a supercritical fluid as a medium is higher. For example, carbon dioxide has the critical temperature of 31.3 ° C and the critical pressure of 72.9 atm, which makes it easy to achieve critical conditions, and has the advantages of being non-toxic and inexpensive, and is therefore most suitable for use as an extraction medium. Since this carbon dioxide is a gas at normal temperature and normal pressure, the supercritical carbon dioxide after extracting the metal element is changed to normal temperature,
The medium is vaporized by returning to normal pressure, the medium can be easily separated completely from the extract, and the metal element contained in the medium can be recovered in the acid solution. The medium recovered by vaporization can be reused without purification.
【００１０】二酸化炭素を抽出媒体として用いたときの
超臨界抽出の装置を図１に示した。液化二酸化炭素ボン
ベ１及び抽出剤収納容器２からそれぞれ二酸化炭素と抽
出剤を必要量シリンジポンプ３へ注入する。シリンジポ
ンプ内で所定の温度に調整した後、二酸化炭素と抽出剤
の混合物を臨界温度、臨界圧力以上の温度、圧力で抽出
部へ注送する。抽出部は予備加熱用コイル４、抽出容器
５、リストリクター６及び捕集容器７から構成され、こ
れらすべては臨界温度以上の温度に保たれた恒温層８中
に設置されている。予備加熱用コイルは抽出部に導入し
た二酸化炭素と抽出剤の混合物の温度を超臨界温度以上
に保つために用いられる。抽出容器に採取した試料水溶
液中に超臨界流体を連続的に導入する。リストリクター
は圧力を常圧に戻すための機能を持つ。捕集容器中には
金属を回収するための酸水溶液を満たす。また未反応の
抽出剤もここに捕集される。気体状態になった二酸化炭
素のみ系外に導出され捕集される。FIG. 1 shows an apparatus for supercritical extraction when carbon dioxide is used as an extraction medium. A required amount of carbon dioxide and an extractant are injected into the syringe pump 3 from the liquefied carbon dioxide cylinder 1 and the extractant storage container 2, respectively. After adjusting the temperature to a predetermined temperature in the syringe pump, the mixture of carbon dioxide and the extractant is pumped to the extraction unit at a temperature and pressure higher than the critical temperature and the critical pressure. The extraction unit includes a preheating coil 4, an extraction container 5, a restrictor 6, and a collection container 7, all of which are installed in a constant temperature layer 8 maintained at a temperature equal to or higher than the critical temperature. The preheating coil is used to maintain the temperature of the mixture of carbon dioxide and the extractant introduced into the extraction section at a supercritical temperature or higher. The supercritical fluid is continuously introduced into the sample aqueous solution collected in the extraction container. The restrictor has a function to return the pressure to normal pressure. The collection container is filled with an aqueous acid solution for recovering the metal. Unreacted extractant is also collected here. Only gaseous carbon dioxide is led out of the system and collected.
【００１１】[0011]
【実施例】以下、本発明を実施例に基づいて説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
【００１２】本実施例は、抽出媒体となる無機物として
二酸化炭素を、中性有機抽出剤としてリン酸−ｎ−トリ
ブチルを、対象金属として希土類元素を用いたときの超
臨界流体抽出の結果である。This embodiment is a result of supercritical fluid extraction when carbon dioxide is used as an inorganic substance serving as an extraction medium, n-tributyl phosphate is used as a neutral organic extractant, and a rare earth element is used as a target metal. .
【００１３】各々３×１０-4Ｍの濃度の希土類元素イオ
ン、すなわちランタン(III)、セリウム(III)、サマリウ
ム(III)、ユウロピウム(III)、ガドリニウム(III)、ジ
スプロシウム(III)、イッテルビウム(III)、ルテチウム
(III)を含む６Ｍ硝酸＋３Ｍ硝酸リチウム水溶液８mlを
抽出容器に採取する。モル比０.０７のリン酸トリ−ｎ
−ブチル（２４ｇ）を含む二酸化炭素１.２モル（５３
ｇ）を３５０気圧、６０℃の条件下の超臨界流体とし、
約４g/min の速度で抽出容器中の試料溶液に注入し、抽
出操作を行った。約２０分の抽出で以下に示す抽出率を
得た。Each of the rare earth element ions having a concentration of 3 × 10 -4 M, ie, lanthanum (III), cerium (III), samarium (III), europium (III), gadolinium (III), dysprosium (III), ytterbium ( III), Lutetium
8 ml of a 6M nitric acid + 3M lithium nitrate aqueous solution containing (III) is collected in an extraction container. Tri-n phosphate with a molar ratio of 0.07
1.2 mol of carbon dioxide containing butyl (24 g) (53 g).
g) as a supercritical fluid under the conditions of 350 atm and 60 ° C.,
The solution was poured into the sample solution in the extraction container at a rate of about 4 g / min to perform an extraction operation. The extraction rate shown below was obtained after about 20 minutes of extraction.
【００１４】 金属元素 ランタン セリウム サマリウム ユウロピウム 抽出率 ８４％ ８４％ ９４％ ９５％ 金属元素 カドリニウム ジスプロシウム イッテルビウム ルテチウム 抽出率 ９４％ ９８％ ８９％ ９４％ [0014] Metal element Lanthanum Cerium Samarium Europium Extraction rate 84% 84% 94% 95% Metal element Cadolinium Dysprosium Ytterbium Lutetium Extraction rate 94% 98% 89% 94%
【００１５】[0015]
【発明の効果】本発明においては、超臨界二酸化炭素を
媒体として硝酸水溶液からの希土類元素を効率よく抽出
分離、回収することができた。さらに超臨界二酸化炭素
を抽出媒体として用いることによって、従来用いられて
きた有機溶媒を用いる液／液分配抽出法よりも優れた抽
出が達成できた。二酸化炭素を抽出物から逆抽出法など
によらず、容易かつ安全に分離することができた。媒体
に起因する放射性廃棄物の発生量を圧倒的に低減できる
ことがわかった。According to the present invention, rare earth elements can be efficiently extracted, separated and recovered from an aqueous nitric acid solution using supercritical carbon dioxide as a medium. Further, by using supercritical carbon dioxide as the extraction medium, extraction superior to the conventional liquid / liquid partition extraction method using an organic solvent could be achieved. Carbon dioxide could be easily and safely separated from the extract without using the back extraction method. It was found that the amount of radioactive waste generated by the medium can be greatly reduced.
【００１６】また、本発明は、有機溶媒の代わりに常
温、常圧下で気体である無機物の超臨界流体を抽出媒体
として用いることにより、作業上の安全性の向上、放射
性廃棄物の減量化を計るものであり、そして従来の有機
溶媒に比べコストも低減できる。Further, the present invention improves the operational safety and reduces the amount of radioactive waste by using an inorganic supercritical fluid, which is a gas at normal temperature and normal pressure, as an extraction medium instead of an organic solvent. It can be measured and costs can be reduced compared to conventional organic solvents.
【図１】本発明の超臨界抽出装置の構造を示した図であ
る。FIG. 1 is a diagram showing a structure of a supercritical extraction device of the present invention.
１…二酸化炭素ボンベ、 ２…抽出剤収納容器、３…
シリンジポンプ、 ４…予備加熱用コイル、 ５
…抽出容器、６…リストリクター、 ７…捕集容
器、 ８…恒温層、９…ガス精製器、
１０…ポンプ用温度コントローラー、１０…シリンジ
ポンプコントロール部。1: Carbon dioxide cylinder, 2: Extractant storage container, 3:
Syringe pump, 4 Pre-heating coil, 5
... extraction container, 6 ... restrictor, 7 ... collection container, 8 ... constant temperature bed, 9 ... gas purifier,
10: temperature controller for pump; 10: syringe pump control unit.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 目黒 義弘 茨城県那珂郡東海村白方字白根２番地の ４ 日本原子力研究所東海研究所内 (58)調査した分野(Int.Cl.6，ＤＢ名) G21C 19/46 C22B 3/00────────────────────────────────────────────────── ─── of the front page continued (72) inventor Yoshihiro Meguro Ibaraki Prefecture Naka-gun, Tokai-mura Shirokata shaped Shirane address 2 of 4 Japan atomic Energy research Institute Tokai the laboratory (58) investigated the field (Int.Cl. 6, DB name ) G21C 19/46 C22B 3/00
Claims (1)
体と有機性抽出剤との混合物を加温、加圧することによ
り超臨界状態の流体とし、この流体を金属元素を溶解し
た硝酸酸性溶液に導入し、硝酸酸性溶液中から金属元素
を流体中に抽出分離し、ついで抽出操作後の超臨界流体
を常温、常圧に戻して硝酸水溶液中に注入することによ
り、抽出媒体として用いた無機物を気化させて除去する
と同時に、金属元素を硝酸水溶液中に回収する方法。1. A supercritical fluid by heating and pressurizing a mixture of an inorganic extraction medium and an organic extractant, which are gaseous at normal temperature and normal pressure, to form a fluid in a supercritical state. The extraction of the metal element from the nitric acid acidic solution into the fluid is carried out by extraction and separation.The supercritical fluid after the extraction operation is returned to normal temperature and normal pressure and injected into the nitric acid aqueous solution to thereby obtain the inorganic substance used as the extraction medium. And removing the metal elements in an aqueous nitric acid solution at the same time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21719494A JP2813551B2 (en) | 1994-09-12 | 1994-09-12 | Extraction and separation of metal elements using supercritical fluid as medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21719494A JP2813551B2 (en) | 1994-09-12 | 1994-09-12 | Extraction and separation of metal elements using supercritical fluid as medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0882696A JPH0882696A (en) | 1996-03-26 |
| JP2813551B2 true JP2813551B2 (en) | 1998-10-22 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21719494A Expired - Fee Related JP2813551B2 (en) | 1994-09-12 | 1994-09-12 | Extraction and separation of metal elements using supercritical fluid as medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2813551B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3524743B2 (en) * | 1997-12-12 | 2004-05-10 | 三菱重工業株式会社 | Reprocessing of spent LWR fuel |
| JP2017146127A (en) * | 2016-02-15 | 2017-08-24 | 株式会社島津製作所 | Component extraction device |
| CN115180709B (en) * | 2022-07-06 | 2023-08-22 | 深圳市华尔信环保科技有限公司 | Oil extraction wastewater treatment and supercritical multi-element hot fluid generation system |
-
1994
- 1994-09-12 JP JP21719494A patent/JP2813551B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0882696A (en) | 1996-03-26 |
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