JPH0631849B2 - Method for solidifying iodine-containing alkaline waste liquid - Google Patents
Method for solidifying iodine-containing alkaline waste liquidInfo
- Publication number
- JPH0631849B2 JPH0631849B2 JP58227535A JP22753583A JPH0631849B2 JP H0631849 B2 JPH0631849 B2 JP H0631849B2 JP 58227535 A JP58227535 A JP 58227535A JP 22753583 A JP22753583 A JP 22753583A JP H0631849 B2 JPH0631849 B2 JP H0631849B2
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- Prior art keywords
- iodine
- waste liquid
- solution
- solidifying
- containing alkaline
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Description
【発明の詳細な説明】 〔発明の利用分野〕 本発明はヨウ素の同位体を主成分とする放射性物質を含
むアルカリ性の廃液を固化し、安定な形態として処理す
るに好適な含ヨウ素アルカリ性廃液の固化処理方法に関
する。The present invention relates to an iodine-containing alkaline waste liquid suitable for solidifying an alkaline waste liquid containing a radioactive substance containing an iodine isotope as a main component and treating it as a stable form. The present invention relates to a solidification treatment method.
アクチナイド元素の中性子照射によつて生ずる核***反
応の結果多種の核***生成物核種を生成する。As a result of fission reaction caused by neutron irradiation of actinide elements, various fission product nuclides are produced.
例えば、二酸化ウランの焼結体をジルコニウム合金製の
被覆管に封入してなる軽水炉燃料を原子炉で使用する
と、核***生成物のうち、そのものまたはその先行核種
が構成する物質が揮発しやすい場合には二酸化ウラン焼
結体と被覆管の間の空所に一部分が放出する。For example, when a light water reactor fuel in which a sintered body of uranium dioxide is enclosed in a cladding tube made of a zirconium alloy is used in a nuclear reactor, if the substance that is itself or the preceding nuclide among the fission products is likely to volatilize, Is partially released into the space between the uranium dioxide sintered body and the cladding.
上記の使用済燃料を剪断してから硝酸に溶解し溶解液か
らある種の有機溶媒を用いてウランとウランの中性子吸
収核反応によつて生成したプルトニウムを抽出分離し、
高い放射能を有する核***生成物を硝酸溶液中に残す操
作、いわゆる再処理を行うことはウラン資源を有効に利
用するのみならず核***生成物を安全に廃棄して原子力
エネルギーを利用する上で環境に及ぼす影響を最少にす
るための減容、固定化処理操作の主要な前半部をなして
いる。Plutonium produced by the neutron absorption nuclear reaction of uranium and uranium is extracted and separated from the solution by shearing the above-mentioned spent fuel and then dissolving it in nitric acid and using a certain organic solvent from the solution.
The operation of leaving fission products with high radioactivity in nitric acid solution, so-called reprocessing, is not only effective use of uranium resources but also safe disposal of fission products and environment for using nuclear energy. It is a major part of the volume reduction and immobilization procedure to minimize its impact on
再処理工程のうち、特に、核燃料の剪断および溶解を含
む部分は機械的前処理工程と呼ばれているが、この過程
で一部の核***生成物は溶解液に至らず、後の工程とは
別の操作によつて処理される。すなわち、使用済核燃料
を剪断する際に燃料被覆管内の空所に蓄積し、あるい
は、二酸化ウラン焼結体の内部に包蔵されていた気体状
の物質が放出する。この物質は実質的にゼノン、クリプ
トンなどの放射性同位体を含む核種とトリチウムあるい
はトリチウムを含んだ水蒸気である。これらの気体は剪
断時放出気体と呼ばれる。続いて、剪断片の溶解を行う
際には、二酸化ウラン焼結体中に包蔵されていたすべて
の気体状物質が放出されさらに硝酸溶液から気相中に放
出する。ここでゼノン、クリプトン、トリチウムなどの
気体状元素のほか溶解中の物理・化学的条件によつて揮
発性を有する物質が含まれる。これらにはヨウ素、臭
素、セシウムおよびその化合物ならびに炭素、トリチウ
ム、ルテニウムなどを含んだ化合物が含まれる。また、
二酸化ウランが硝酸に溶解する際には硝酸が分解して種
々の酸化窒素を生ずるし、この酸化窒素を酸化して硝酸
に戻すため溶解液に酸素を吹き込む場合には過剰の酸素
が混入する。これらの気体は溶解時放出気体と呼ばれ
る。Of the reprocessing process, the part that includes the shearing and melting of nuclear fuel is called the mechanical pretreatment process, but some fission products do not reach the dissolution liquid in this process, and the latter process is It is processed by another operation. That is, when the spent nuclear fuel is sheared, the gaseous substance accumulated in the void in the fuel cladding tube or enclosed in the uranium dioxide sintered body is released. This substance is substantially a radionuclide containing xenon or krypton and tritium or water vapor containing tritium. These gases are called shear released gases. Subsequently, when the shear fragments are dissolved, all the gaseous substances contained in the uranium dioxide sintered body are released and further released from the nitric acid solution into the gas phase. Here, in addition to gaseous elements such as Zenon, krypton, and tritium, substances that are volatile depending on the physical and chemical conditions during dissolution are included. These include iodine, bromine, cesium and its compounds as well as compounds containing carbon, tritium, ruthenium and the like. Also,
When uranium dioxide is dissolved in nitric acid, the nitric acid decomposes to produce various nitric oxides, and when oxygen is blown into the solution in order to oxidize the nitric oxide and return it to nitric acid, excess oxygen is mixed. These gases are called released gases upon dissolution.
剪断時および溶解時放出気体は通常空気の流れに伴つて
負圧に保たれた放出気体処理系に導かれる。The released gas at the time of shearing and at the time of melting is usually guided to the released gas processing system kept at a negative pressure along with the flow of air.
放出気体処理系の構成の代表的な一例としてはまず、放
出気体中の硝酸溶液ミスト、硝酸蒸気などを主として吸
収除去するための水洗浄装置があり、ここでは酸化窒素
のかなりの部分、ヨウ素の一部、トリチウムを含んだ水
の一部が液相に移つて放出気体から除去される。続い
て、苛性ソーダでアルカリ性に保たれた洗浄装置があ
り、ここでは残つた酸化窒素の一部分、ヨウ素の大部
分、トリチウムを含んだ水の一部分が液相に移つて除去
される。上記の洗浄装置では放出気体中に含まれるセシ
ウムあるいはルテニウムの化合物も吸収される。ヨウ素
化合物の中には酸性またはアルカリ性の水には吸収しな
いものがあり、洗浄装置を通過したものは別に処理を要
する場合がある。As a typical example of the configuration of the release gas treatment system, first, there is a water cleaning device for mainly absorbing and removing nitric acid solution mist in the release gas, nitric acid vapor, etc. Some of the tritiated water is transferred to the liquid phase and removed from the evolved gas. Next, there is a washing device kept alkaline with caustic soda, in which part of the remaining nitric oxide, most of the iodine, and part of the water containing tritium are transferred to the liquid phase and removed. In the above cleaning device, the compound of cesium or ruthenium contained in the released gas is also absorbed. Some iodine compounds do not absorb into acidic or alkaline water, and those that have passed through the cleaning device may require separate treatment.
アルカリ溶液洗浄装置を通過した気体の主成分は酸素に
富んだ空気と、ゼノンおよびクリプトンなどの稀ガスお
よび少量のトリチウム水である。通常は、水素を混合し
た後再結合触媒を通して酸素を水に変換した後、水を乾
燥除去し、続いて低温蒸溜法を用い、沸点の差を利用し
て窒素からゼノンおよびクリプトンを分離する。The main components of the gas passed through the alkaline solution cleaning device are air rich in oxygen, rare gases such as Zenon and krypton, and a small amount of tritiated water. Usually, hydrogen is mixed and oxygen is converted to water through a recombination catalyst, and then water is dried and removed, and then a low temperature distillation method is used to separate xenon and krypton from nitrogen by utilizing a difference in boiling points.
上記の放出気体処理系構成において、本発明が関係する
ところはアルカリ溶液洗浄工程であつて洗浄工程のアル
カリ性廃液の処理方法に直接関係する。In the above-mentioned discharged gas treatment system configuration, the present invention is concerned with the alkaline solution washing step and directly with the alkaline waste liquid treating method in the washing step.
アルカリ溶液洗浄工程から発生する廃液の代表的な組成
は苛性ソーダ（ＮａＯＨ：分子量４０ｇ／モル）硝酸ソ
ーダ（ＮａＮＯ３：分子量８５ｇ／モル）およびヨウ化
ソーダ（ＮａＩ：分子量１５０ｇ／モル、ただしヨウ素
は質量数１２９の同位体）を主成分とする水溶液で微量
のルテニウム、セシウムの酸化物を含むものと考えられ
る。The typical composition of the waste liquid generated from the alkaline solution washing step is caustic soda (NaOH: molecular weight 40 g / mol) sodium nitrate (NaNO 3 : molecular weight 85 g / mol) and sodium iodide (NaI: molecular weight 150 g / mol, provided that iodine is mass). It is considered to be an aqueous solution containing the isotope of 129 as a main component and containing a trace amount of oxides of ruthenium and cesium.
この放射性廃液の環境に対する影響は短期的には質量数
１０６のルテニウム同位体（半減期：３６７日）中期的
には質量数１３７のセシウム同位体（半減期の３０年）
などが支配的であるが、長期的には質量数１２９のヨウ
素同位体（半減期１．７×１０７年）が重要である。質
量数１２９のヨウ素の放射能は比較的長半減期の核***
生成物の全放射能の一億分の一に過ぎないが、一千年程
度貯蔵された後の核***生成物の環境に対する影響の度
合は全くこのヨウ素同位体の存在に依存している。The environmental impact of this radioactive liquid waste is a ruthenium isotope with a mass number of 106 (half-life: 367 days) in the short term, and a cesium isotope with a mass number of 137 (half-life of 30 years) in the medium term.
, Etc. are dominant, but in the long term, an iodine isotope with a mass number of 129 (half-life: 1.7 × 10 7 years) is important. The radioactivity of iodine with a mass number of 129 is only one hundred millionth of the total radioactivity of fission products with a relatively long half-life, but the environmental impact of fission products after being stored for about 1,000 years The degree depends entirely on the presence of this iodine isotope.
従つて、放射性ヨウ素を含有したアルカリ性吸収液の処
理にあたつては放射性ヨウ素を長期にわたつて安定な状
態で生物環境と隔離する必要がある。Therefore, in treating the alkaline absorbent containing radioactive iodine, it is necessary to isolate radioactive iodine from the biological environment in a stable state over a long period of time.
剪断時および溶解時放出気体のアルカリ溶液洗浄処理は
簡便な方法であるが含ヨウ素アルカリ性廃液の処分には
適当な方法が見出されていない難点がある。The alkaline solution cleaning treatment of the released gas at the time of shearing and dissolution is a simple method, but there is a drawback that an appropriate method has not been found for the disposal of the iodine-containing alkaline waste liquid.
放射性廃液の処分に際して採用される通常の方法には、
濃縮による減容、脱水乾燥、濃縮液のセメントまたはア
スフアルトあるいはプラスチツク固体などの組合わせに
より、いずれにしても環境において安定な固体とするこ
とが含まれる。The usual methods used to dispose of radioactive liquid waste include:
Any combination of reducing the volume by concentrating, dehydrating and drying, and combining the concentrated liquid with cement or asphalt or plastic solid, etc., makes it a stable solid in the environment.
含ヨウ素アルカリ性廃液の処分にあたつては次のような
理由で困難さを伴つている。Disposal of iodine-containing alkaline waste liquid is difficult for the following reasons.
（イ）濃縮過程におけるヨウ素の揮発 （ロ）苛性ソーダ水溶液の脱水乾燥は困難 （ハ）酸で中和すればヨウ素の揮発促進 （ニ）ナトリウム塩の高い水溶性 （ホ）濃苛性ソーダの混和剤との非共存性 〔発明の目的〕 本発明の目的は、含ヨウ素アルカリ性廃液に最少の添加
剤を加えて処理することによりヨウ素の揮発を抑制しな
がら安定で処分に好適な固体とする。(A) Volatilization of iodine in the concentration process (b) It is difficult to dehydrate and dry the aqueous solution of caustic soda. (C) Acceleration of volatilization of iodine by neutralizing with acid (d) High water solubility of sodium salt (e) Admixture of concentrated caustic soda [Objective of the Invention] The object of the present invention is to add iodine to an alkaline waste liquid containing a minimum amount of the additive to treat it, thereby making it a solid which is stable and suitable for disposal while suppressing volatilization of iodine.
本発明は、含ヨウ素アルカリ性廃液中でヨウ素はイオン
として存在する限りは安定であり、酸化作用によつて元
素状となれば揮発しやすくなるため還元性雰囲気に保ち
ながらアルミニウムを添加してアルミン酸ナトリウム水
溶液となし、さらに無水硅酸を添加して反応せしめ、最
終的に酸化ナトリウム、酸化アルミニウム、酸化硅素お
よび若干の水を主成分とし、ヨウ素を固定する安定な固
体とするようにしたものである。In the present invention, iodine is stable as long as it exists as an ion in an iodine-containing alkaline waste liquid, and if it becomes elemental due to an oxidizing action, it easily volatilizes, so that aluminum is added while maintaining a reducing atmosphere and aluminate is added. It was made into an aqueous solution of sodium and further reacted by adding silicic acid anhydride to finally make sodium oxide, aluminum oxide, silicon oxide and some water as main components, and to make it a stable solid that fixes iodine. is there.
本発明の要点を順に追つて説明すれば、まず、還元性雰
囲気に保ちながらアルカリ性廃液にアルミニウムを添加
する操作は金属アルミニウムを苛性ソーダ水溶液と反応
せしめ、発生する水素ガスによつて硝酸イオンを亜硝酸
イオンからさらにアンモニヤまで還元せしめ、また、ヨ
ウ素は元素状として溶解していたものもイオン状とす
る。この操作を続けることにより、アルミン酸ナトリウ
ムを生成せしめることができる。Explaining the main points of the present invention step by step, first, the operation of adding aluminum to the alkaline waste liquid while maintaining a reducing atmosphere is to react metallic aluminum with an aqueous solution of caustic soda, and generate nitric acid ions by the hydrogen gas generated. Ions are further reduced to ammonium, and iodine dissolved in elemental form is converted into ionic form. By continuing this operation, sodium aluminate can be produced.
アルミン酸ナトリウムのアルカリ性水溶液に無水硅酸を
反応せしめて沸石類（ゼオライト類）と呼ばれる鉱物種
を合成することは良く知られている（原伸宜、高橋浩
「ゼオライト、基礎と応用」講談社、１９７４年、）。
ただし、本発明の要点に係わるところはこの段階におい
てもヨウ素をイオン状またはヨウ化物の形態に保つてお
くことで、これによつて最終的に形成した固化物中にヨ
ウ素は安定に化合される。It is well-known to synthesize mineral species called zeolites (zeolites) by reacting silicic acid anhydride with an alkaline aqueous solution of sodium aluminate (Nobuyoshi Hara, Hiroshi Takahashi "Zeolite, Fundamentals and Applications" Kodansha, 1974,).
However, the important point of the present invention is that iodine is kept in an ionic or iodide form even at this stage, whereby iodine is stably compounded in the solidified product finally formed. .
沸石類の人工鉱物は強酸によつては分解するが中性、ア
ルカリ性の水には溶解せず結晶格子内にイオンを包蔵で
きることが知られており、含ヨウ素アルカリ性廃液中に
共存する放射性核種は固化体中に固定されてしまう。Zeolites artificial minerals are decomposed by strong acid, but it is known that they are not dissolved in neutral or alkaline water and can contain ions in the crystal lattice. It is fixed in the solidified body.
放射性同位元素で汚染したアルミニウム約１．５ｇを３
モル／の苛性ソーダ水溶液２２ｍｌに溶解し、その溶
液を撹拌しながら乾燥したシリカゲル粉末（１００〜２
００メツシユ）３．５〜１６．３ｇｒ（アルミニウムに
対し、１〜５当量）を徐々に添加して上記のシリカゲル
添加範囲でいずれも固化体を得た前例がある。（本島健
次他「原子炉照射したＵＯ２からの真空昇華法による
９９Ｍｏの製造研究」ＪＡＥＲＩＩ−Ｍｅｍｏ ９７５
３，ｐ．５．）。About 1.5 g of aluminum contaminated with radioactive isotope
A silica gel powder (100 to 2) which was dissolved in 22 ml of a mol / caustic soda aqueous solution and dried while stirring the solution.
There is a precedent example in which 3.5 to 16.3 gr (1 to 5 equivalents relative to aluminum) was gradually added to obtain a solidified product in the above silica gel addition range. (Kenji Motojima et al. “Vacuum sublimation method from UO 2 irradiated by nuclear reactor”
99 Mo manufacturing research ”JAERII-Memo 975
3, p. 5. ).
本発明の要点は上記の従来知見にもとづいて行われたも
ので、その特徴は放射性物質を含んだ苛性アルカリ液に
アルミニウムとケイ素を添加して固化するところにあ
り、特に金属アルミニウムの溶解時に発生する水素の還
元作用を積極的に利用してヨウ素の遊離を抑制しながら
固化体中に固定するところにある。The gist of the present invention is based on the above-mentioned conventional knowledge, and its characteristic is that aluminum and silicon are added to a caustic alkali solution containing a radioactive substance to solidify, and particularly when metallic aluminum is dissolved. The positive action is to reduce the release of iodine by positively utilizing the reducing action of hydrogen.
（実施例１） ＮａＯＨ４％、ＮａＮＯ３０．７％、ＮａＩ０．３％を
含有するアルカリ性模擬廃液をそれぞれ３倍および６倍
に濃縮した溶液を用いて、まず金属Ａｌを溶解し、続い
て１００〜２００メツシユのシリカゲルを添加して撹拌
した後室温に放置し、約１時間後の固化状態をＮａ量に
対するＡｌとＳｉの添加モル量をパラメータとして試験
を行い、第１図に結果を示した。Example 1 Using a solution obtained by concentrating an alkaline simulated waste liquid containing NaOH 4%, NaNO 3 0.7% and NaI 0.3% 3 times and 6 times, respectively, first, metal Al was dissolved, and then 100% was dissolved. ~ 200 mesh silica gel was added, and the mixture was stirred and allowed to stand at room temperature, and the solidified state after about 1 hour was tested using the added molar amount of Al and Si with respect to the Na amount as a parameter, and the results are shown in FIG. .
６倍濃縮すなわち、ＮａＯＨで２４％のアルカリ性溶液
の場合にはＡｌ／Ｎａモル比が０．７〜１．０でＳｉ／
Ｎａモル比が０．９〜１．２の範囲で良好な固化体が得
られることがわかつた。一方、３倍または２倍濃縮のア
ルカリ性溶液では良好な固化体が得られなかつた。Six-fold concentration, that is, in the case of a 24% alkaline solution with NaOH, the Al / Na molar ratio is 0.7 to 1.0 and Si /
It has been found that a good solidified product can be obtained when the Na molar ratio is in the range of 0.9 to 1.2. On the other hand, a good solidified product could not be obtained with a three-fold or two-fold concentrated alkaline solution.
シリカゲルを添加して撹拌後１時間を経過した固化体は
比重が約１．５であり、重量収支から計算した含水量は
対Ｎａモル比で４．５モルであつた。アルカリ水溶液へ
のＡｌの溶解およびシリカゲルと混合時に約１０％の減
量が観察された。The specific gravity of the solidified product, to which silica gel had been added and 1 hour had passed after stirring, was about 1.5, and the water content calculated from the weight balance was 4.5 mol in terms of Na molar ratio. About 10% weight loss was observed upon dissolution of Al in aqueous alkaline solution and mixing with silica gel.
固化体を空気中で１５０℃に加熱すると重量は約３０％
減じて固化体の比重は約１．０となつた。５００℃以上
７００℃まで加熱しても減量はほとんどなく固化体の形
状は良好に保たれた。When the solidified body is heated to 150 ° C in air, the weight is about 30%.
The specific gravity of the solidified body was reduced to about 1.0. Even if heated to 500 ° C. or higher and 700 ° C., there was almost no weight loss, and the shape of the solidified body was kept good.
固化体の空気流中加熱において、２５０℃以上でヨウ素
を発生した。When the solidified body was heated in the air flow, iodine was generated at 250 ° C. or higher.
比較のために純Ａｌ金属のかわりに、Ｃｕを約５％含有
するＡｌ合金を用いて実験を行つたところ、固化体の状
態は純Ａｌを用いた場合よりやや劣り、特に加熱時には
崩壊する傾向があり、また、加熱時のヨウ素発生はやや
低温で観察された。For comparison, when an experiment was conducted using an Al alloy containing about 5% Cu instead of pure Al metal, the state of the solidified body was slightly inferior to the case of using pure Al, and it tended to collapse when heated. In addition, iodine generation during heating was observed at a rather low temperature.
固化体試料についてのＸ線回折格子常数測定によつて
は、常温放置試料ではＮａ２Ａｌ２Ｏ４・６Ｈ２Ｏのみ
が見出され、１５０℃に加熱した試料ではＮａＡｌＳｉ
Ｏ４が見出され、７００℃に加熱した試料ではさらにＮ
ａ２Ｏ・Ａｌ２Ｏ３・ＳｉＯ４が見出されゼオライト様
結晶が存在することが確認された。Connexion by the X-ray diffraction lattice constant measurements for solidified samples, only Na 2 Al 2 O 4 · 6H 2 O is found in the left at room temperature samples, NaAlSi the sample heated to 0.99 ° C.
O 4 was found and more N was found in the sample heated to 700 ° C.
It was confirmed that a 2 O.Al 2 O 3 .SiO 4 was present and that zeolite-like crystals were present.
６倍濃縮液から生成した固化体の容積は濃縮溶液の約
１．３倍であつた。The volume of the solidified product produced from the 6-fold concentrated solution was about 1.3 times that of the concentrated solution.
以上の結果から、使用時にはＮａＯＨ４％であつた含ヨ
ウ素アルカリ性廃液は６倍に濃縮すればＮａ：Ａｌ：Ｓ
ｉ＝１：０．７〜１．０：０．９５〜１．２の組成範囲
で良好な固化体を生成することがわかつた。この固化体
の体積はＮａＯＨ４％であつた含ヨウ素アルカリ廃液の
体積と比較して約２０％となつており１／５に減容した
ことになる。この固化体は脱水しても安定であり、少な
くとも２００℃においてはヨウ素を遊離しないことが確
かめられている。From the above results, the iodine-containing alkaline waste liquid, which was 4% NaOH at the time of use, should be concentrated 6 times to produce Na: Al: S.
It was found that a good solidified product was produced in the composition range of i = 1: 0.7 to 1.0: 0.95 to 1.2. The volume of this solidified body is about 20% compared to the volume of the iodine-containing alkali waste liquid which was 4% of NaOH, which means that the volume was reduced to 1/5. It has been confirmed that this solidified product is stable even when dehydrated and does not release iodine at least at 200 ° C.
この固化体は特に他のマトリツクスの共用しなくとも長
期にわたり安定であると考えられるが、不浸透性のマト
リツクスとともに容器に充填すればより安定化が可能で
ある。It is considered that this solidified body is stable for a long period of time even if it is not shared with other matrices, but it can be further stabilized by filling it in a container together with an impermeable matrix.
本実施例において、Ａｌ／Ｎａのモル比を１以上に大き
くし、あるいはＳｉ／Ｎａのモル比を１．２以上に大き
くしても良好な固化体を得ることができるが原廃液に対
する固化体の減容比はＡｌおよびＳｉの添加量を増やせ
ば低下するため好ましくない。In this example, a good solidified body can be obtained even if the Al / Na molar ratio is increased to 1 or more, or the Si / Na molar ratio is increased to 1.2 or more. The volume reduction ratio of is decreased as the amount of Al and Si added is increased, which is not preferable.
また、原廃液の濃縮の度合を６倍より低下した場合でも
５倍まではＳｉの添加量を増加すれば良好な固化体を得
るが、上記のとおり減容比の上で好ましくはない。さら
に、濃縮の度合を６倍以上とした場合でも８倍以上とす
ることは固化体の耐熱性を低下させることが見出されて
いる。Further, even if the concentration of the raw waste liquid is reduced to less than 6 times, a good solidified body can be obtained by increasing the addition amount of Si up to 5 times, but this is not preferable in terms of volume reduction ratio as described above. Further, it has been found that even if the degree of concentration is 6 times or more, if it is 8 times or more, the heat resistance of the solidified product is lowered.
（実施例２） ＮａＯＨ４０ｇ／、ＮａＮＯ３７ｇ／、ＮａＩ３ｇ
／を含有するアルカリ性模擬廃液１あたり２７ｇの
純Ａｌ金属を溶解した。Ａｌの溶解は発熱反応であり、
一たん反応を開始すると急激に進行するため溶融へのＡ
ｌの添加は回分的に行なう必要があつた。ＮａＮＯ３は
Ａｌの溶解時に発生する水素で還元されＮＨ３ガスとし
て放出した。(Example 2) NaOH 40 g /, NaNO 3 7 g /, NaI 3 g
27 g of pure Al metal was dissolved per 1 of the alkaline simulated waste liquid containing /. The dissolution of Al is an exothermic reaction,
Once the reaction starts, it rapidly progresses.
The addition of 1 had to be done batchwise. NaNO 3 was reduced by hydrogen generated when Al was dissolved and released as NH 3 gas.
ＮａＡｌＯ２として約８２ｇ／を含有する溶液は蒸発
濃縮装置を用いて水を除去し、ＮａＡｌＯ２として約５
６０ｇ／を含有する濃縮溶液とした。A solution containing about 82 g / as NaAlO 2 has water removed using an evaporative concentrator to give about 5 as NaAlO 2.
It was a concentrated solution containing 60 g /.
蒸発濃縮は縦型の遠心薄膜蒸発装置によつて行われ、濃
縮の過程で原液中のヨウ素の揮発は０．５％であつた。The evaporative concentration was carried out by a vertical centrifugal thin film evaporator, and the evaporation of iodine in the stock solution was 0.5% during the concentration process.
ＮａＡｌＯ２として約５６０ｇ／、ＮａＩとして約２
０ｇ／含有した濃縮溶液は溶液１あたり４２０ｇの
シリカゲル（１００〜２００メツシユ）と常温でオーガ
ー（真空土練機）で混練した。混合物は最初ばさばさし
た状態のフアニキユラー域流動状態を示すが混練が進む
に従つてねばねばした状態のキヤビラリー域状態に変る
（化学工学協会編、化学工学便覧、昭５３年丸善、ｐ．
１３５４〜１３５５．）。この状態で混練装置から押し
出し、容器に充填する。約１時間室温で放置することに
よつて固化した。About 560g / as NaAlO 2 and about 2 as NaI
The concentrated solution of 0 g / containing was kneaded with 420 g of silica gel (100 to 200 mesh) per solution at room temperature with an auger (vacuum kneader). The mixture first shows a state of fluidity in the Fananikylar region in a loose state, but as the kneading progresses, it changes into a state of a sticky state in a slimy state (Chemical Engineering Handbook, Chemical Engineering Handbook, Maruzen 1978, p. 53).
1354-1355. ). In this state, it is extruded from the kneading device and filled in a container. It solidified by standing at room temperature for about 1 hour.
本実施例による方法は工業的規模で、連続的な含ヨウ素
アルカリ性廃液の固化処理を可能とした。アルカリ性模
擬廃液を原液のままで蒸発濃縮すると原液中のヨウ素は
約２％揮発することが見出されており、本実施例の方法
では約０．５％に低下している。ヨウ素の揮発は遠心薄
膜蒸発装置内部を運転中に窒素などの不活性雰囲気とす
ることによつてさらに０．１％程度に低下させることが
できている。また、アルカリ性原液にＡｌ金属を添加す
る際に、ヨウ素含量とモル当量のＳｎ（金属錫）を添加
し溶解させることにより、蒸発濃縮時のヨウ素揮発は全
く検知できないようになつた。The method according to the present embodiment is capable of continuously solidifying the iodine-containing alkaline waste liquid on an industrial scale. It has been found that when the alkaline simulated waste liquid is evaporated and concentrated as it is, about 2% of the iodine in the stock solution is volatilized, and it is reduced to about 0.5% by the method of this example. The volatilization of iodine can be further reduced to about 0.1% by making the inside of the centrifugal thin film evaporator an inert atmosphere such as nitrogen during operation. Further, when Al metal was added to the alkaline stock solution, by adding and dissolving Sn (metal tin) in a molar equivalent to the iodine content, iodine volatilization at the time of evaporative concentration could not be detected at all.
本実施例におけるＮａ：Ａｌ：Ｓｉのモル比は前述の実
施例１において見出された好適な固化体を得るための組
成範囲と合致している。The Na: Al: Si molar ratio in this example is consistent with the composition range for obtaining a suitable solidified body found in the above-mentioned Example 1.
（実施例３） 第２図は実施例その３において、アルカリ性模擬廃液と
Ａｌ金属とを好適に反応させるための装置の概略図であ
る。(Example 3) FIG. 2 is a schematic view of an apparatus for suitably reacting the alkaline simulated waste liquid with Al metal in Example 3 of the present invention.
反応容器１は不銹鋼製で縦型の筒状である。ホツパ２は
金属アルミニウム片３をフイーダ４で反応容器内に供給
する。反応容器は給液管５、排液管６、還流冷却器７、
保守ホール８が接続されている。反応容器内には運転中
は給液管５の開口部より高いレベルまで金属アルミニウ
ム片が充填されている。還流冷却器７には排気管９が接
続されている。不活性ガス導入管１０がホツパに接続さ
れている。The reaction vessel 1 is made of stainless steel and has a vertical cylindrical shape. The hopper 2 supplies the metal aluminum piece 3 into the reaction vessel by means of the feeder 4. The reaction vessel is a liquid supply pipe 5, a drainage pipe 6, a reflux condenser 7,
The maintenance hole 8 is connected. During operation, the reaction container is filled with metal aluminum pieces to a level higher than the opening of the liquid supply pipe 5. An exhaust pipe 9 is connected to the reflux condenser 7. The inert gas introducing pipe 10 is connected to the hopper.
本装置の運転は、あらかじめ反応容器の内部を規定のレ
ベルまで金属アルミニウム片で満たした後、給液管を通
して、ＮａＯＨ４％、ＮａＮＯ３７％、ＮａＩ０．３％
を含有するアルカリ性模擬廃液を供給した。液は反応容
器中の金属アルミニウム片充填層内を流下する過程でア
ルミニウムと反応し、ＮａＡｌＯ２を生成するとともに
Ｈ２ガスを発生し、また、液中の硝酸塩が還元分解して
ＮＨ３ガスが発生する。アルミニウムの溶解反応は発熱
反応であるため加熱された溶液からは水蒸気を発生し、
アルカリ溶液のミストを伴つて液の流下と対向して上昇
する。アルカリ溶液のミストはアルミニウム片充填層に
付着して反応する。水蒸気は還流冷却器で水となり反応
容器内に戻される。The operation of this device was performed by previously filling the inside of the reaction vessel with metal aluminum pieces to a specified level and then passing through a liquid supply pipe, NaOH 4%, NaNO 3 7%, NaI 0.3%.
Alkaline simulated waste liquor containing The liquid reacts with aluminum in the process of flowing down in the metal aluminum piece packed bed in the reaction vessel to generate NaAlO 2 and generate H 2 gas, and the nitrate in the liquid is reductively decomposed to generate NH 3 gas. Occur. Since the dissolution reaction of aluminum is an exothermic reaction, steam is generated from the heated solution,
It rises in opposition to the flow of liquid with a mist of alkaline solution. The mist of the alkaline solution adheres to and reacts with the packed aluminum piece layer. The steam becomes water in the reflux condenser and is returned to the reaction vessel.
反応容器内での反応速度はアルカリ溶液への供給速度を
制御することで制御される。必要なだけ反応の進んだ溶
液は反応容器の底部に滞溜しているが排液管から排出さ
れる。The reaction rate in the reaction container is controlled by controlling the supply rate to the alkaline solution. The solution, which has reacted as much as necessary, remains in the bottom of the reaction container but is discharged from the drain pipe.
反応容器内は不活性ガス導入管からの不活性ガスで内部
を置換し、反応生成物であるＨ２やＮＨ３などの可燃性
気体が空気と爆発性の混合気を生成することを防止す
る。The inside of the reaction vessel is replaced with an inert gas from an inert gas introduction pipe to prevent a combustible gas such as H 2 or NH 3 which is a reaction product from generating an explosive mixture with air. .
ここで反応生成液は、ＮａＡｌＯ２として約８％を含有
している。この溶液にシリカゲルを約６％添加して撹拌
し溶解させた後、遠心薄膜蒸発装置を用いて脱水し、乾
燥した粉粒体を製造した。Here, the reaction product liquid contains about 8% as NaAlO 2 . About 6% of silica gel was added to this solution, and the mixture was stirred and dissolved, and then dehydrated using a centrifugal thin film evaporator to produce dried powder and granules.
粉粒体の組成は、実施例１で良好な固化体の加熱乾燥体
と近似したものである。粉粒体の嵩比重は０．７であつ
た。遠心薄膜蒸発装置の内部は運転中に不活性雰囲気に
保たれ、原液中のヨウ素の揮発は０．１％以下に止つ
た。The composition of the powder and granules is similar to that of the heat-dried product of the good solidified product in Example 1. The bulk specific gravity of the powder and granules was 0.7. The inside of the centrifugal thin film evaporator was kept in an inert atmosphere during the operation, and the volatilization of iodine in the stock solution was kept to 0.1% or less.
本実施例によつては、固化体が粉粒体となるため特に圧
粉操作を行わないと容器中への充填体として減容効果が
実施例その２の場合より劣る。しかし、溶液の蒸発と混
練が１ステツプで実施することができた。According to the present example, since the solidified body becomes powdery particles, the volume reduction effect as a filling body into the container is inferior to that in the case of Example 2 unless the powder compacting operation is performed. However, the evaporation and kneading of the solution could be carried out in one step.
本実施例の変形として、遠心薄膜蒸発装置の運転条件を
制御することにより、脱水率を低下させキヤビラリー域
状態の流体として取出し、容器に充填してから固化させ
ることも可能である。As a modification of this embodiment, it is also possible to lower the dehydration rate by controlling the operating conditions of the centrifugal thin-film evaporation device, extract it as a fluid in a canary region, fill it in a container, and then solidify it.
前述した本発明の各実施例においては内容に差異はある
がその要旨は還元性の雰囲気、状態に保ちながら含ヨウ
素アルカリ性廃液にアルミニウムを添加し、生成したア
ルミン酸ナトリウム水溶液にシリカゲルを添加してゼオ
ライト様組成の固体を生成せしめるところにある。Although there is a difference in contents in each of the examples of the present invention described above, the gist thereof is to add aluminum to the iodine-containing alkaline waste liquid while maintaining a reducing atmosphere and state, and to add silica gel to the generated sodium aluminate aqueous solution. This is where solids with a zeolite-like composition are produced.
ここで、アルミニウムとして金属をアルカリ性廃液に溶
解し、発生する水素の還元作用を利用しつつアルミニウ
ムを添加しているが、一部のアルミニウムは水酸化アル
ミニウムのような水以外に固化体の増量をきたす成分を
含まないアルミニウム化合物として添加しても本発明の
効果を損ずることはない。水酸化アルミニウムのような
アルミニウム化合物の添加は他の還元作用、すなわち金
属錫の溶解または第一錫塩の添加などと併用しても効果
を減ずることはない。Here, as aluminum, a metal is dissolved in an alkaline waste liquid, and aluminum is added while utilizing the reducing action of generated hydrogen. However, some aluminum has an increased solidification amount other than water such as aluminum hydroxide. Even if added as an aluminum compound containing no inducing component, the effect of the present invention is not impaired. The addition of an aluminum compound such as aluminum hydroxide does not reduce the effect even if it is used in combination with another reducing action, that is, dissolution of metallic tin or addition of stannous salt.
また、前述の実施例では１００〜２００メツシユのシリ
カゲルを使用しているが、シリカゲルの粒度は必らずし
も本発明の効果を減じない。粒径が大きくなると反応速
度を減ずるが、粒径が小さくなれば反応速度が大きくな
り同時に急速に固化が進むため固化体の調製制御が困難
となる場合がある。本発明の効果は硅酸または硅酸ゾル
を添加反応させても必ずしも減ずるものではないが反応
速度の制御または水分の除去に関して配慮を要する。Moreover, although 100 to 200 mesh silica gel is used in the above-mentioned embodiment, the particle size of silica gel does not necessarily reduce the effect of the present invention. When the particle size becomes large, the reaction rate decreases, but when the particle size becomes small, the reaction rate increases and at the same time solidification progresses rapidly, which may make it difficult to control the preparation of the solidified body. The effect of the present invention is not necessarily reduced even when the reaction of addition of silicic acid or silicic acid sol is carried out, but attention must be paid to control of reaction rate or removal of water.
シリカゲル等の添加に際して、ヨウ素と反応して不活性
で比較的耐熱性のある化合物を生成する元素を金属粉末
状で添加することを試みた。銅粉末または鉛粉末をヨウ
素のモル含量の２倍モル量だけ添加して固化体を作成し
た。鉛を添加した固化体は少なくともヨウ化鉛（ＰｂＩ
２）の融点である４１２℃まで加熱しても元素状のヨウ
素を遊離することはなかつた。銅を添加した固化体はヨ
ウ化銅（ＣｕＩ）は変態点である４０２℃より低い温度
で明らかにヨウ素を遊離した。従つて、鉛粉末の添加は
固化体中のヨウ素をより安定化する作用を有するもので
ある。At the time of adding silica gel or the like, it was attempted to add an element which reacts with iodine to form an inactive and relatively heat-resistant compound in the form of a metal powder. Copper powder or lead powder was added in an amount twice the molar content of iodine to prepare a solidified body. The solidified body to which lead is added is at least lead iodide (PbI
Even when heated to 412 ° C., which is the melting point of 2 ), elemental iodine was not liberated. In the solidified body to which copper was added, copper iodide (CuI) clearly released iodine at a temperature lower than the transformation point of 402 ° C. Therefore, the addition of lead powder has a function of further stabilizing the iodine in the solidified body.
含ヨウ素アルカリ性廃液にアルミニウムとシリカを添加
して生成した良好な固化体は生成時で約４０％の水分を
含有している。この含水固化体を１５０℃で加熱してお
くと約３５％の減量を示し、水分を失つたものと考えら
れる。含ヨウ素アルカリ性廃液の固化体を貯蔵すに際し
て乾燥するかどうかは容器充填の方法によつて定めるべ
きパラメータであり、いずれにしても本発明の目的に合
致することができる。A good solidified product produced by adding aluminum and silica to the iodine-containing alkaline waste liquid contains about 40% of water at the time of production. When this hydrous solidified body was heated at 150 ° C., it showed a weight loss of about 35%, and it is considered that water was lost. Whether to dry the solidified body of the iodine-containing alkaline waste liquid is a parameter to be determined by the method of filling the container, and in any case, it can meet the object of the present invention.
本発明によれば、その主成分としてＮａＯＨ，ＮａＮＯ
３，ＮａＩを含む含ヨウ素アルカリ性廃液からのヨウ素
の揮発を抑制しつつ最少の物質を添加することにより減
容化され、かつ、安定で処分に好適な固化体とすること
ができる。According to the present invention, the main components are NaOH and NaNO.
3. A solidified product which is reduced in volume and stable and suitable for disposal can be obtained by adding a minimum amount of substance while suppressing volatilization of iodine from an iodine-containing alkaline waste liquid containing NaI.
第１図は、本発明に係わり良好な固化体を得るためのア
ルミニウムおよびケイ素の添加量の範囲を示す関係図、
第２図は本発明に係わる金属アルミニウムと苛性アルカ
リ溶液の反応装置の構成を示す略線図である。 １……反応容器、２……ホツパ、３……金属アルミニウ
ム片、４……フイーダ、５……給液管、６……排液管、
７……還流冷却器、８……保守ホール、９……排気管、
１０……不活性ガス導入管。FIG. 1 is a relational diagram showing a range of addition amounts of aluminum and silicon for obtaining a good solidified body according to the present invention.
FIG. 2 is a schematic diagram showing the structure of a reaction apparatus for metallic aluminum and a caustic solution according to the present invention. 1 ... Reactor container, 2 ... Hopper, 3 ... Metal aluminum piece, 4 ... Feeder, 5 ... Supply pipe, 6 ... Drain pipe,
7 ... reflux condenser, 8 ... maintenance hall, 9 ... exhaust pipe,
10 ... Inert gas introduction pipe.
Claims (6)
性アルカリ水溶液に苛性アルカリの１モルあたりに０．
７〜１．０モルの金属アルミニウムを添加して溶解し、
続いて溶解液を水含量が約３５〜４５％となるように濃
縮し、しかるのち原液の苛性アルカリの１モルあたりに
０．９〜１．２モルのシリカゲルを添加して攪拌した後
に放置して固化せしめることを特徴とする含ヨウ素アル
カリ性廃液の固化処理方法。1. In a caustic aqueous solution obtained by cleaning a gas containing NOx and iodine, a molar ratio of 0.
7-1.0 mol of aluminum metal is added and dissolved,
Subsequently, the solution was concentrated to a water content of about 35 to 45%, 0.9 to 1.2 mol of silica gel was added to 1 mol of caustic alkali in the stock solution, and the mixture was stirred and allowed to stand. A method for solidifying an iodine-containing alkaline waste liquid, which is characterized in that it is solidified.
ミニウムを添加した含ヨウ素アルカリ濃縮溶液とシリカ
ゲルの混合物を貯蔵容器に移してから固化させることを
特徴とする含ヨウ素アルカリ性廃液の固化処理方法。2. The method for solidifying an iodine-containing alkaline waste liquid according to claim 1, wherein a mixture of the concentrated iodine-containing alkaline solution containing metallic aluminum and silica gel is transferred to a storage container and then solidified. .
カリ溶液と金属アルミニウムの反応を金属アルミニウム
片を充填し、不活性雰囲気に保った塔状反応容器内を苛
性アルカリ溶液を流下させることによって行わせること
を特徴とする含ヨウ素アルカリ性廃液の固化処理方法。3. The method according to claim 1, wherein the reaction of the caustic solution and metallic aluminum is filled with metallic aluminum pieces, and the caustic solution is made to flow down in a tower-shaped reaction vessel kept in an inert atmosphere. A method for solidifying an iodine-containing alkaline waste liquid, which is characterized by being performed.
発濃縮または固化にいたる操作を窒素などの不活性気体
の雰囲気中で行うことを特徴とする含ヨウ素アルカリ性
廃液の固化処理方法。4. The method for solidifying an iodine-containing alkaline waste liquid according to claim 1, wherein the operation of evaporating and concentrating or solidifying the solution is performed in an atmosphere of an inert gas such as nitrogen.
ルの添加に伴って金属鉛の粉末を混合することを特徴と
する含ヨウ素アルカリ性廃液の固化処理方法。5. A method for solidifying an iodine-containing alkaline waste liquid according to claim 1, wherein powder of metallic lead is mixed with the addition of silica gel.
き金属アルミニウムの一部を水酸化アルミニウムに置換
し、さらに第１錫イオンを添加することを特徴とする含
ヨウ素アルカリ性廃液の固化処理方法。6. The solidification treatment of an iodine-containing alkaline waste liquid according to claim 1, wherein a part of metallic aluminum to be added is replaced with aluminum hydroxide, and stannous ions are further added. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58227535A JPH0631849B2 (en) | 1983-11-30 | 1983-11-30 | Method for solidifying iodine-containing alkaline waste liquid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58227535A JPH0631849B2 (en) | 1983-11-30 | 1983-11-30 | Method for solidifying iodine-containing alkaline waste liquid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60119499A JPS60119499A (en) | 1985-06-26 |
| JPH0631849B2 true JPH0631849B2 (en) | 1994-04-27 |
Family
ID=16862422
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58227535A Expired - Lifetime JPH0631849B2 (en) | 1983-11-30 | 1983-11-30 | Method for solidifying iodine-containing alkaline waste liquid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0631849B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH077099B2 (en) * | 1988-09-26 | 1995-01-30 | 動力炉・核燃料開発事業団 | Recovery and storage method of radioactive iodine by freeze-vacuum drying method |
| TW365009B (en) * | 1996-09-24 | 1999-07-21 | Jgc Corp | Method of disposal of metallic aluminum-containing radioactive solid waste |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5551716A (en) * | 1978-10-06 | 1980-04-15 | British Petroleum Co | Manufacture of amorphous alminosilicate and its application to catalyst |
-
1983
- 1983-11-30 JP JP58227535A patent/JPH0631849B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5551716A (en) * | 1978-10-06 | 1980-04-15 | British Petroleum Co | Manufacture of amorphous alminosilicate and its application to catalyst |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60119499A (en) | 1985-06-26 |
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