JPH0324997B2 - - Google Patents
Info
- Publication number
- JPH0324997B2 JPH0324997B2 JP11784784A JP11784784A JPH0324997B2 JP H0324997 B2 JPH0324997 B2 JP H0324997B2 JP 11784784 A JP11784784 A JP 11784784A JP 11784784 A JP11784784 A JP 11784784A JP H0324997 B2 JPH0324997 B2 JP H0324997B2
- Authority
- JP
- Japan
- Prior art keywords
- phosphoric acid
- electrodeposition
- liquid
- electrolyte
- regeneration
- 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
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 130
- 238000000605 extraction Methods 0.000 claims description 79
- 239000007788 liquid Substances 0.000 claims description 77
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 65
- 238000004070 electrodeposition Methods 0.000 claims description 59
- 239000003792 electrolyte Substances 0.000 claims description 57
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 53
- 238000011069 regeneration method Methods 0.000 claims description 43
- 230000008929 regeneration Effects 0.000 claims description 42
- 238000000034 method Methods 0.000 claims description 40
- 238000005202 decontamination Methods 0.000 claims description 37
- 230000003588 decontaminative effect Effects 0.000 claims description 35
- 239000002904 solvent Substances 0.000 claims description 19
- 239000000243 solution Substances 0.000 claims description 16
- 229910021645 metal ion Inorganic materials 0.000 claims description 14
- STCOOQWBFONSKY-UHFFFAOYSA-N tributyl phosphate Chemical compound CCCCOP(=O)(OCCCC)OCCCC STCOOQWBFONSKY-UHFFFAOYSA-N 0.000 claims description 13
- 238000005868 electrolysis reaction Methods 0.000 claims description 12
- 239000008151 electrolyte solution Substances 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 11
- 239000000284 extract Substances 0.000 claims description 9
- 230000002285 radioactive effect Effects 0.000 claims description 3
- 239000000356 contaminant Substances 0.000 claims 1
- 230000001172 regenerating effect Effects 0.000 claims 1
- 238000000926 separation method Methods 0.000 description 24
- 238000001704 evaporation Methods 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 8
- 238000012545 processing Methods 0.000 description 6
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000004043 dyeing Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 4
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- -1 hydrogen ions Chemical class 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000012141 concentrate Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- PHTQWCKDNZKARW-UHFFFAOYSA-N isoamylol Chemical compound CC(C)CCO PHTQWCKDNZKARW-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZAFNJMIOTHYJRJ-UHFFFAOYSA-N Diisopropyl ether Chemical compound CC(C)OC(C)C ZAFNJMIOTHYJRJ-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910052770 Uranium Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000000622 liquid--liquid extraction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000012857 radioactive material Substances 0.000 description 1
- 239000000941 radioactive substance Substances 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000008400 supply water Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
Landscapes
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Electrolytic Production Of Metals (AREA)
- Fuel Cell (AREA)
- ing And Chemical Polishing (AREA)
Description
本発明は、原子力発電所等において放射能汚染
された機器、部品類の電解除染に使用したリン酸
系高濃度酸除染電解液の隔膜電解による電着再生
方法に関する。
放射能汚染された機器、部品類を電解研磨によ
り除染する電解除染工程で電解液として5%硫酸
等の強酸希薄水溶液を用いると、研磨速度が大き
く、また隔膜電解による除染電解液の電着再生処
理が容易にできるので、この電解液は放射能汚染
された廃棄物の除染用電解液としては最適である
が、除染後の金属表面が粗く、放射性物質によつ
て再汚染されやすくなるので再使用を目的とした
容器の内面あるいは部品類の除染用電解液として
使用する場合には問題がある。再使用を目的とし
た対象物の電解除染に用いる電解液として一般の
電解研摩に使われる高濃度酸電解液のうちリン酸
系の高濃度酸電解液を用いると、除染後の金属表
面が光択化され放射性物質による再汚染が最も少
なくなる。しかし、この電解液を隔膜電解により
電着再生することは、電解液の酸濃度が高いた
め、これまで困難とされ、電解除染工程で電解液
中の溶存金属イオン濃度あるいは放射線量が一定
値に達した時点でこの電解液をプラスチツク固化
あるいはセメント固化処理して廃棄している。し
かし、このような処理方法は放射性二次廃棄物を
増加させる点で問題がある。
本願出願人は、このような高濃度酸除染電解液
の隔膜電解による電着再生方法について研究開発
をすすめ、特願昭58−198114(特開昭60−89600号
公報参照)および特願昭59−37466(特開昭60−
17900号公報参照)を出願した。
前者の方法は、隔膜で仕切つた電着再生槽の陰
極室に電解除染工程で使用した電解液を収容し、
陽極室に少量の電解液を加えて導電性をよくした
水を収容して回分処理により除染電解液の電着再
生処理を行なうものであるが、陰極室の捕集電極
で液中の金属イオンを電着捕集するためには陰極
室液の水素イオン濃度をPH2程度にまで低下させ
なければならないので、電着捕集が開始されるま
でに長い時間がかかり、また、この間に隔膜を通
して陰極室から陽極室への金属イオンのリークが
生じるので、陽極室液を電解液として再利用する
場合の除染能力に悪影響を与える。
後者の方法は、回分処理による前記の問題を解
決するため、電着再生槽の陰極室には水、陽極室
には金属イオンを含まない電解液をあらかじめ収
容しておき、陰極室液の水素イオン濃度をPH2前
後に保つよう電解除染工程の電解液をPHコントロ
ールしながら陰極室に注入し、その注入量と同量
の陽極室液を引抜いて電解除染工程に戻すように
して連続処理により除染電解液の電着再生処理を
行ない、通電当初から金属イオンの電着捕集がで
きるようにしたものであるが、酸濃度の高い除染
電解液を陰極室に直接注入するためその注入量を
多くして電着再生の処理能力を増すには設備が過
大となる問題がある。
本発明は、除染後の再汚染防止効果の高いリン
酸系高濃度酸除染電解液の電着再生方法につき、
前記先願の方法に改良を加えて電着再生時間の短
縮あるいは処理能力を向上させることを目的と
し、電解除染工程で使用した高濃度のリン酸系除
染電解液を電着再生槽へ送る前に、除染電解液中
のリン酸を溶媒で抽出してその抽出分離液(リン
酸の減つた電解液)を電着再生槽の陰極室に送
り、リン酸抽出後の溶媒から水でリン酸を逆抽出
してその逆抽出液(金属イオンをほとんど含まな
いリン酸水溶液)を電着再生槽の陽極室に送り、
陰極室で液中の金属イオンを電着捕集するととも
に陽極室で液中のリン酸を初期の電解液濃度にま
で濃縮し除染電解液として再使用するものであ
る。
リン酸水溶液からリン酸を液一液抽出する溶媒
としては、イソプロピルエーテル、エチレンメノ
メチルエーテル、ノルマルブチルアルコール、イ
ソアミルアルコール、メチルイソブチルケトン、
ブチルアセテート等、多くの溶媒があるが、これ
らの有機溶媒は除染電解液の熱によつて蒸発し引
火性があるので、いずれも電着再生工程で使用す
るリン抽出剤としては適当でない。各種リン抽出
剤について探索した結果、水に不溶で不燃性のリ
ン酸トリブチル(TBP)が除染電解液の電着再
生工程で用いるリン抽出剤として最も有効である
ことがわかつた。
リン酸トリブチルは金属抽出剤として知られて
おり、硝酸中のウランの抽出等に使われている
が、除染電解液中の鉄、ニツケル、クローム、コ
バルト等の金属イオンはほとんど抽出せずリン酸
をよく抽出し、水による逆抽出でリン酸および金
属イオンはほぼ完全に逆抽出される。そして沸点
が高く蒸発減量がないので補充なしで繰返し使用
することができる。
以下、溶媒によるリン酸の抽出、逆抽出を利用
した除染電解液の電着再生方法の実施例につい
て、図面に基づいて詳細に説明する。
電解除染工程ではリン酸系の高濃度酸を電解液
として使用し、電解除染槽1の電解液中に、表面
が放射能汚染された被除染物2を設置してこれを
整流器(図示せず)の陽極に接続し、電解液中の
陰極3との間に直流電流を流して被除染物2の表
面を電解研摩により除染する。
第1図に示す実施例の電着再生工程では、被除
染物2の表面から溶出した放射性金属イオンを含
む除染電解液をポンプ4により電解除染槽1から
引抜き、この除染電解液を溶媒によるリン酸抽出
と水によるリン酸逆抽出によつて、リン酸の減つ
た電解液と金属イオンをほとんど含まないリン酸
水溶液に分離した後、これらの液をそれぞれ電着
再生槽5の陰極室6と陽極室7に送り、隔膜8を
介して陰極室6内の捕集電極9と陽極室7内の不
溶性電極10との間に直流電流を流して回分処理
により電着再生槽5で除染電解液の電着再生処理
を行ない、初期の電解液濃度にまでリン酸が濃縮
された陽極室7の液をポンプ11で電解除染槽1
へ返送する。
前記のリン酸の抽出および逆抽出は、下半部分
に溶媒Sを貯留した抽出分離槽12で行なう。そ
の操作については第2図イ〜ニを併用して説明す
る。
電解除染槽1からは、陽極室7の容量と等しい
量の除染電解液13をポンプ4で抽出分離槽12
に供給し、撹拌機14を起動して液を撹拌混合
し、電解液13中のリン酸を溶媒Sで抽出する。
撹拌機14を停止後、下層に分離された抽出分離
液15を排出弁16から陰極室6に排出する。抽
出分離液15の排出は電気伝導度計17で監視し
ながら行ない、溶媒Sを陰極室6に排出しないよ
うにする。排出された抽出分離液15は陰極室6
の容量より量が少ないので給水弁18を開いて陰
極室6の上限レベルまで水を補給する。
次に貯水槽19の給水弁20を開いて抽出分離
槽12に逆抽出用水21を供給し、撹拌機14を
起動して液を撹拌混合し、溶媒S中のリン酸を逆
抽出する。撹拌機14停止後、下層に分離された
逆抽出液22を排出弁23を開いて陽極室7の上
限レベルまで注入する。逆抽出液22の量は除染
電解液13よりも量が多くなつているので、その
大部分は抽出分離槽12に残る。
この状態で捕集電極9と不溶性電極10との間
に直流通電すると、陰極室6では液中の陽イオン
である水素イオンが捕集電極9面で多量の水素ガ
スとなつて放出されて液の水素イオン濃度が低下
し、それにともなつて陰イオンであるリン酸イオ
ンが隔膜8を通つて陽極室7に移動する。陽極室
7では不溶性電極10面での酸素ガス発生によつ
て増加した水素イオンが陰極室6から移動して来
たリン酸イオンと結びついて液中のリン酸が次第
に濃縮される。通電継続により陰極室6で液の水
素イオン濃度がPH2前後にまで低下すると、捕集
電極9面では水素ガスの発生量が減少し、液中の
金属イオンの電着が開始される。
この通電過程において、電着再生槽5では水の
電気分解および蒸発によつて水分が放出され陰極
室6陽極室7とも水分減量によつて液面が低下す
るので、陰極室6では給水弁18から補給水を自
動供給して液面調整し、陽極室7では抽出分離槽
12に残つた逆抽出液22を排出弁23から自動
供給して液面調整する。
抽出分離槽12からの逆抽出液22のほぼ完全
排出が電気伝導度計17によつて検知されると、
液面調節機能を解除して排出弁23を閉鎖し、そ
のまま通電を継続して陰極室6の液中に金属イオ
ンもリン酸イオンもほとんど存在しなくなつた時
点で通電を停止する。電解除染槽1から送られた
電解液13は、この時点で最終的にほぼ同容量の
高濃度リン酸として再生されたことになるので、
必要に応じて給水弁24から水を加えてリン酸の
濃度を初期の電解液濃度に調整し、ポンプ11で
陽極室7液の全量を電解除染槽1へ返送して除染
電解液の電着再生処理が終了する。
次回の逆抽出操作にそなえて貯水槽19には給
水弁25から水を補給するが、この電着再生工程
では陰極室6で清水に近い水が生成されるので、
電着再生終了後に陰極室6の液をポンプ26で貯
水槽19に送つて逆抽出用水の一部として循環使
用する。
この方法では、陰極室6へ供給される抽出分離
液15はリン酸の減つた電解液であり、また給水
弁18からの補給水で希釈され、陰極室6では水
素イオン濃度が低下した状態で通電が開始される
ので、陰極室6に高濃度の除染電解液をそのまま
収容して電着再生を行なう前記先願の方法と比較
すると、電着開始までの時間が著るしく短縮され
る。
第3図の実施例においては、リン酸の抽出、逆
抽出の工程および電着再生の工程を連続化したも
ので、第1図と共通の項目については共通の符号
を使用し、説明の重複を省略する。
リン酸抽出および逆抽出の工程では、抽出槽3
0、抽出液分離槽31および逆抽出槽32、逆抽
出液分離槽33を別個に設置して液が順次オーバ
ーフローして流れるようにして、溶媒Sを逆抽出
液分離槽33からポンプ34で抽出槽30に常時
循環させ、抽出槽30と逆抽出槽32ではそれぞ
れ撹拌機35,36により液を常時撹拌する。
電解除染槽1からの除染電解液はポンプ4で抽
出槽30へ連続送給して溶媒Sによるリン酸の抽
出を連続して行ない、抽出液分離槽31で分離さ
れ下層に溜つた抽出分離液15を供給弁37か
ら、陰極室6の液が常にPH2前後に維持されるよ
うPHコントロールしながら陰極室6に供給する。
抽出液分離槽31の溶媒Sは逆抽出槽32に移行
して、給水弁20から供給される水によつてリン
酸が逆抽出され、逆抽出液分離槽33で下層に分
離された逆抽出液22を供給弁38で液面コント
ロールしながら陽極室7に供給する。逆抽出槽3
2には、逆抽出液分離槽33での液面制御によ
り、抽出分離液15および逆抽出液22の排出量
に応じた量の逆抽出用水が貯水槽19から給水弁
20を通じて自動供給される。
陰極室6では、ポンプ39により液が常時循環
撹拌され、抽出分離液15の自動注入で液が常時
PH2前後に維持されるため、抽出分離液15中の
金属イオンは遅滞なく捕集電極9で電着捕集され
る。電気分解および蒸発による水の減量に対して
は給水弁40から水を補給してレベル調整を行な
うが、水の減量分より抽出分離液15の注入量が
多い場合には陰極室6の液面が次第に上昇するの
で、液面が上限に達した時点でPH調節を解除して
抽出分離液15の注入を停止して通電を継続し、
陰極室6の液中に金属イオンもリン酸イオンもほ
とんど存在しなくなつた状態で循環ラインの弁4
1を切換えて陰極室6液の一部を貯水槽19へ送
り、陰極室6の液面を低下させる。
陽極室7では、水の減量分だけ逆抽出液22を
自動供給し、液中のリン酸濃度を電気伝導度計1
7で監視しながらポンプ11の送液量を調節して
陽極室7の液を再生ずみ電解液として電解除染槽
1に返送し、それに等しい量の電解液を電解除染
槽1からポンプ4で抽出槽30へ送るようにし
て、連続的に電着再生処理を行なう。
この方法によると、第1図の実施例と同様に、
陰極室6へ注入される抽出分離液15がリン酸の
減つた電解液であるから、電解除染槽1から送ら
れる電解液を直接陰極室6へ注入して電着再生を
行なう前記先願の方法と比較すると、電着再生の
処理能力を向上させることができる。
これらの実施例では、電解除染槽1から送られ
る除染電解液中のリン酸が抽出逆抽出により、前
もつて陽極室7側に移行するので、電着再生の過
程で陰極室6から陽極室7へ隔膜8を通してリン
酸を移行させるための電気エネルギーが節約され
る。しかし、リン酸抽出逆抽出の効果を高めるた
めに多量の逆抽出用水を使用すると、それだけ陽
極室7で処理すべき逆抽出液22の量が増加し、
電着再生の速度が電気分解および蒸発による陽極
室7での水の減量速度で制限されるようになる。
陽極室7でのリン酸濃縮に蒸発濃縮を併用すると
この問題は解消されるが、陽極室7での液の加熱
は隔膜8の機能を低下させ、陽極室7から陰極室
6への水素イオンのリークが生じるようになるの
で、蒸発濃縮を併用する場合には、陽極室7へ注
入する逆抽出液22を前もつて濃縮するか、ある
いは陽極室7の液を蒸発装置に送つて液を濃縮
し、冷却された濃縮液を陽極室7に受入れるよう
にしなければならない。
第4図は、逆抽出液22中のリン酸濃縮に蒸発
濃縮を併用した一例であり、分離槽12,33か
ら受槽50に排出した逆抽出液22を蒸気圧縮式
濃縮装置51に送つてリン酸の濃縮を行なう。濃
縮器52内面グラスライニングした容器またはパ
イプを使用し、圧縮機53で蒸気を吸引して器内
を減圧すると同時に吸引した蒸気を圧縮してジヤ
ケツト54または外面グラスライニングした伝熱
管等で圧縮熱を器内の液に伝達して低い温度で逆
抽出液22の蒸発濃縮を行なうので、蒸発濃縮の
ための消費エネルギーが少なく、熱源も冷却水も
不要である。器内の濃縮液はポンプ55で吸引し
て陽極室7へ送り、凝縮水は貯水槽19へ送つて
逆抽出用水として循環使用する。
このように逆抽出液22のリン酸濃縮に蒸発濃
縮を併用すると、電着再生の過程では水の電気分
解のための余分の電力消費が減り、十分な逆抽出
用水を使用してより完全な抽出と逆抽出ができる
ので、電着再生の速度あるいは処理量をさらに向
上させることができる。
本発明の方法におけるリン酸の抽出と逆抽出の
効果を確認するため、電解液として75%リン酸で
SUS304板を電解除染した使用ずみ電解液、溶媒
としてリン酸トリブチル(TBP)を使用して、
次の抽出、逆抽出試験を行なつた。
上記電解液10c.c.にTBP40c.c.を加えて電解液中
のリン酸を抽出し、リン酸を抽出したTBPに水
50c.c.を加えてリン酸を逆抽出し、リン酸逆抽出に
より再生されたTBPに再び上記電解液10c.c.を加
える抽出、逆抽出の操作を繰返すと10c.c.の電解液
はリン酸が抽出されて7c.c.に減量し、リン酸を抽
出したTBP43c.c.に水50c.c.を加えてリン酸を逆抽
出すると再生TBPは初期の40c.c.に戻り、りん酸
を含んだ逆抽出液53c.c.が得られるようになる。
使用した電解液A10c.c.、および第2回目と第5
回目の抽出、逆抽出操作で得られた抽出分離液
B7c.c.、逆抽出液C53c.c.、再生TBPD40c.c.中にそれ
ぞれ含まれる成分は次表の通りである。
The present invention relates to a method for electrodeposition regeneration using diaphragm electrolysis of a phosphoric acid-based high-concentration acid decontamination electrolyte used for electrolytic decontamination of radioactively contaminated equipment and parts in nuclear power plants and the like. If a strong acid dilute aqueous solution such as 5% sulfuric acid is used as the electrolyte in the electrolytic decontamination process in which radioactively contaminated equipment and parts are decontaminated by electrolytic polishing, the polishing speed is high, and the decontamination electrolyte by diaphragm electrolysis is This electrolyte is ideal as an electrolyte for decontaminating radioactively contaminated waste because it can be easily reprocessed by electrodeposition, but the surface of the metal after decontamination is rough and may be recontaminated with radioactive materials. This poses a problem when used as an electrolytic solution for decontaminating the inner surfaces of containers or parts intended for reuse. Among the high-concentration acid electrolytes used in general electrolytic polishing, phosphoric acid-based high-concentration acid electrolytes are used as electrolytes for electrolytic de-dying of objects intended for reuse. is photo-selected and re-contamination with radioactive substances is minimized. However, it has been difficult to regenerate this electrolyte by electrodeposition using diaphragm electrolysis due to the high acid concentration of the electrolyte, and the dissolved metal ion concentration or radiation dose in the electrolyte remains at a constant level during the electrodeposition process. When the electrolyte reaches this point, it is solidified into plastic or cement and disposed of. However, this treatment method has a problem in that it increases the amount of radioactive secondary waste. The applicant of this application has conducted research and development on a method for electrodeposition regeneration using diaphragm electrolysis for such a highly concentrated acid decontamination electrolyte, and has published Japanese Patent Application No. 1981-114 (see Japanese Patent Application Laid-open No. 89600-1983) and Japanese Patent Application No. 59-37466 (Unexamined Japanese Patent Publication 1986-
(Refer to Publication No. 17900). In the former method, the electrolyte used in the electrodeposition dyeing process is stored in the cathode chamber of an electrodeposition regeneration tank separated by a diaphragm.
The anode chamber is filled with water that has been made conductive by adding a small amount of electrolyte, and the decontamination electrolyte is regenerated by electrodeposition through batch processing. In order to collect ions by electrodeposition, the hydrogen ion concentration in the cathode chamber fluid must be reduced to about PH2, so it takes a long time for electrodeposition collection to start, and during this time, the hydrogen ion concentration in the cathode chamber solution must be reduced to about PH2. Since metal ions leak from the cathode chamber to the anode chamber, this adversely affects the decontamination ability when the anode chamber solution is reused as an electrolyte. In the latter method, in order to solve the above-mentioned problems caused by batch processing, the cathode chamber of the electrodeposition regeneration tank is filled with water and the anode chamber is filled with an electrolytic solution that does not contain metal ions. Continuous processing is performed by injecting the electrolytic solution for the electrolytic dedying process into the cathode chamber while controlling the pH to maintain the ion concentration around PH2, and then withdrawing the same amount of the anodic chamber solution as the injection amount and returning it to the electrolytic dedying process. The decontamination electrolyte was regenerated by electrodeposition using a method that enabled metal ions to be collected by electrodeposition from the beginning of energization, but since the decontamination electrolyte with a high acid concentration was directly injected into the cathode chamber, Increasing the throughput of electrodeposition regeneration by increasing the injection amount poses a problem in that the equipment becomes too large. The present invention relates to a method for electrodeposition regeneration of a phosphoric acid-based high-concentration acid decontamination electrolyte that is highly effective in preventing recontamination after decontamination.
In order to improve the method of the previous application and shorten the electrodeposition regeneration time or improve processing capacity, the highly concentrated phosphoric acid decontamination electrolyte used in the electrodeposition decontamination process was transferred to an electrodeposition regeneration tank. Before sending, the phosphoric acid in the decontamination electrolyte is extracted with a solvent, the extracted separated liquid (electrolyte with reduced phosphoric acid) is sent to the cathode chamber of the electrodeposition regeneration tank, and water is extracted from the solvent after phosphoric acid extraction. phosphoric acid is back-extracted and the back-extracted solution (phosphoric acid aqueous solution containing almost no metal ions) is sent to the anode chamber of the electrodeposition regeneration tank.
The metal ions in the solution are collected by electrodeposition in the cathode chamber, and the phosphoric acid in the solution is concentrated in the anode chamber to the initial electrolyte concentration and reused as a decontamination electrolyte. Solvents for liquid-liquid extraction of phosphoric acid from an aqueous phosphoric acid solution include isopropyl ether, ethylene menomethyl ether, n-butyl alcohol, isoamyl alcohol, methyl isobutyl ketone,
Although there are many solvents such as butyl acetate, these organic solvents are evaporated by the heat of the decontamination electrolyte and are flammable, so none of them are suitable as phosphorus extractants for use in the electrodeposition regeneration process. As a result of searching for various phosphorus extractants, it was found that tributyl phosphate (TBP), which is insoluble in water and nonflammable, is the most effective phosphorus extractant for use in the electrodeposition regeneration process of decontamination electrolytes. Tributyl phosphate is known as a metal extractant and is used to extract uranium from nitric acid, but it hardly extracts metal ions such as iron, nickel, chromium, and cobalt from the decontamination electrolyte, and is Acid is well extracted, and phosphoric acid and metal ions are almost completely extracted by back extraction with water. Since it has a high boiling point and no evaporation loss, it can be used repeatedly without replenishment. Hereinafter, an embodiment of a method for electrodeposition regeneration of a decontamination electrolyte using extraction of phosphoric acid with a solvent and back extraction will be described in detail based on the drawings. In the electrolytic dedying process, a highly concentrated phosphoric acid is used as an electrolytic solution, and the object to be decontaminated 2 whose surface is radioactively contaminated is placed in the electrolytic solution in the electrolytic dedying tank 1, and then it is passed through a rectifier (Fig. The surface of the object 2 to be decontaminated is decontaminated by electropolishing by connecting it to the anode (not shown) and passing a direct current between it and the cathode 3 in the electrolytic solution. In the electrodeposition regeneration process of the embodiment shown in FIG. After separating into an electrolytic solution with reduced phosphoric acid and a phosphoric acid aqueous solution containing almost no metal ions by phosphoric acid extraction with a solvent and phosphoric acid back-extraction with water, these solutions are respectively applied to the cathode of the electrodeposition regeneration tank 5. chamber 6 and anode chamber 7, and a direct current is passed between the collection electrode 9 in the cathode chamber 6 and the insoluble electrode 10 in the anode chamber 7 through the diaphragm 8, and the electrodeposition regeneration tank 5 is subjected to batch processing. The decontamination electrolyte is regenerated by electrodeposition, and the liquid in the anode chamber 7, in which phosphoric acid has been concentrated to the initial electrolyte concentration, is transferred to the decontamination tank 1 using a pump 11.
Send it back to The extraction and back extraction of phosphoric acid described above are performed in an extraction separation tank 12 in which the solvent S is stored in the lower half. The operation will be explained with reference to FIGS. 2A to 2D. From the decontamination tank 1, an amount of decontamination electrolyte 13 equal to the capacity of the anode chamber 7 is extracted using a pump 4 and transferred to a separation tank 12.
The agitator 14 is started to stir and mix the liquid, and the phosphoric acid in the electrolyte 13 is extracted with the solvent S.
After stopping the stirrer 14, the extracted liquid 15 separated into the lower layer is discharged from the discharge valve 16 to the cathode chamber 6. The extraction and separation liquid 15 is discharged while being monitored with an electrical conductivity meter 17 to prevent the solvent S from being discharged into the cathode chamber 6. The discharged extracted separation liquid 15 is transferred to the cathode chamber 6
Since the amount is less than the capacity of the cathode chamber 6, the water supply valve 18 is opened to supply water up to the upper limit level of the cathode chamber 6. Next, the water supply valve 20 of the water storage tank 19 is opened to supply back extraction water 21 to the extraction separation tank 12, and the stirrer 14 is started to stir and mix the liquids, thereby back extracting the phosphoric acid in the solvent S. After the stirrer 14 is stopped, the reverse extraction liquid 22 separated into the lower layer is injected into the anode chamber 7 up to the upper limit level by opening the discharge valve 23. Since the amount of the back extraction liquid 22 is larger than that of the decontamination electrolyte 13, most of it remains in the extraction separation tank 12. When DC current is applied between the collection electrode 9 and the insoluble electrode 10 in this state, in the cathode chamber 6, hydrogen ions, which are cations in the liquid, are released as a large amount of hydrogen gas on the surface of the collection electrode 9, and the liquid is As the hydrogen ion concentration decreases, phosphate ions, which are anions, move to the anode chamber 7 through the diaphragm 8. In the anode chamber 7, hydrogen ions increased by the generation of oxygen gas on the surface of the insoluble electrode 10 combine with the phosphate ions transferred from the cathode chamber 6, and the phosphoric acid in the liquid is gradually concentrated. When the hydrogen ion concentration of the liquid in the cathode chamber 6 decreases to around PH2 due to continued energization, the amount of hydrogen gas generated on the surface of the collection electrode 9 decreases, and electrodeposition of metal ions in the liquid begins. During this energization process, water is released by electrolysis and evaporation in the electrodeposition regeneration tank 5, and the liquid level in both the cathode chamber 6 and the anode chamber 7 decreases due to the loss of water. Makeup water is automatically supplied from the anode chamber 7 to adjust the liquid level, and in the anode chamber 7, the back extraction liquid 22 remaining in the extraction separation tank 12 is automatically supplied from the discharge valve 23 to adjust the liquid level. When almost complete discharge of the back extraction liquid 22 from the extraction separation tank 12 is detected by the electrical conductivity meter 17,
The liquid level adjustment function is canceled and the discharge valve 23 is closed, and the current is continued to be applied. When almost no metal ions or phosphate ions are present in the liquid in the cathode chamber 6, the current is stopped. At this point, the electrolytic solution 13 sent from the de-dyeing tank 1 has finally been regenerated as highly concentrated phosphoric acid with almost the same volume.
If necessary, water is added from the water supply valve 24 to adjust the concentration of phosphoric acid to the initial electrolyte concentration, and the entire amount of the anode chamber 7 solution is returned to the decontamination tank 1 using the pump 11 to prepare the decontamination electrolyte. The electrodeposition regeneration process ends. Water is replenished from the water supply valve 25 to the water storage tank 19 in preparation for the next back extraction operation, but in this electrodeposition regeneration process, water close to fresh water is generated in the cathode chamber 6.
After the electrodeposition regeneration is completed, the liquid in the cathode chamber 6 is sent to the water storage tank 19 by the pump 26, and is circulated and used as part of the water for back extraction. In this method, the extracted separated liquid 15 supplied to the cathode chamber 6 is an electrolyte with reduced phosphoric acid, and is diluted with make-up water from the water supply valve 18, so that the hydrogen ion concentration is reduced in the cathode chamber 6. Since energization is started, the time required to start electrodeposition is significantly shortened compared to the method of the prior application in which electrodeposition regeneration is performed by storing a high concentration decontamination electrolyte in the cathode chamber 6 as it is. . In the example shown in Figure 3, the steps of phosphoric acid extraction, back extraction, and electrodeposition regeneration are serialized, and items common to those in Figure 1 are given the same reference numerals, and explanations will be repeated. omitted. In the process of phosphoric acid extraction and back extraction, extraction tank 3
0. The extract liquid separation tank 31, the back extraction tank 32, and the back extraction liquid separation tank 33 are installed separately so that the liquids sequentially overflow and flow, and the solvent S is extracted from the back extraction liquid separation tank 33 with the pump 34. The liquid is constantly circulated in the tank 30, and the liquid is constantly stirred in the extraction tank 30 and the back extraction tank 32 by agitators 35 and 36, respectively. The decontamination electrolyte from the decontamination tank 1 is continuously fed to the extraction tank 30 by the pump 4, where phosphoric acid is continuously extracted by the solvent S, and the extracted liquid is separated in the extract separation tank 31 and collected in the lower layer. The separated liquid 15 is supplied from the supply valve 37 to the cathode chamber 6 while controlling the pH so that the liquid in the cathode chamber 6 is always maintained at around PH2.
The solvent S in the extract liquid separation tank 31 is transferred to the back extraction tank 32, where phosphoric acid is back extracted by water supplied from the water supply valve 20, and the back extraction liquid is separated into a lower layer in the back extraction liquid separation tank 33. The liquid 22 is supplied to the anode chamber 7 while controlling the liquid level with a supply valve 38. Reverse extraction tank 3
2, by controlling the liquid level in the back extraction liquid separation tank 33, water for back extraction is automatically supplied from the water storage tank 19 through the water supply valve 20 in an amount corresponding to the discharge amount of the extraction separation liquid 15 and the back extraction liquid 22. . In the cathode chamber 6, the liquid is constantly circulated and stirred by the pump 39, and the liquid is constantly circulated by automatic injection of the extraction and separation liquid 15.
Since the pH is maintained around 2, the metal ions in the extracted and separated liquid 15 are collected by electrodeposition at the collection electrode 9 without delay. In response to the loss of water due to electrolysis and evaporation, water is replenished from the water supply valve 40 to adjust the level. However, if the amount of extracted and separated liquid 15 injected is greater than the amount of water lost, the liquid level in the cathode chamber 6 gradually rises, so when the liquid level reaches the upper limit, the PH adjustment is canceled, injection of the extraction separation liquid 15 is stopped, and electricity is continued.
When there are almost no metal ions or phosphate ions in the liquid in the cathode chamber 6, the circulation line valve 4 is closed.
1 is switched to send a part of the liquid in the cathode chamber 6 to the water tank 19 to lower the liquid level in the cathode chamber 6. In the anode chamber 7, the back extraction solution 22 is automatically supplied by the amount of water lost, and the phosphoric acid concentration in the solution is measured using an electrical conductivity meter 1.
The liquid in the anode chamber 7 is returned to the electrolysis dyeing tank 1 as a recycled electrolyte by adjusting the amount of liquid sent by the pump 11 while being monitored by the electrolysis dyeing tank 1 at pump 4. The electrodeposition regeneration process is performed continuously by sending the sample to the extraction tank 30. According to this method, similar to the embodiment of FIG.
Since the extracted separated liquid 15 injected into the cathode chamber 6 is an electrolytic solution with reduced phosphoric acid, the electrolytic solution sent from the electrodepositing tank 1 is directly injected into the cathode chamber 6 to perform electrodeposition regeneration. Compared to the above method, the throughput of electrodeposition regeneration can be improved. In these embodiments, the phosphoric acid in the decontamination electrolyte sent from the electrodeposition dye tank 1 is transferred to the anode chamber 7 side by extraction and back extraction, so that it is removed from the cathode chamber 6 during the electrodeposition regeneration process. The electrical energy for transferring the phosphoric acid through the diaphragm 8 into the anode chamber 7 is saved. However, if a large amount of back extraction water is used to enhance the effect of phosphoric acid extraction back extraction, the amount of back extraction liquid 22 to be treated in the anode chamber 7 increases accordingly.
The rate of electrodeposition regeneration is limited by the rate of water loss in the anode chamber 7 due to electrolysis and evaporation.
This problem can be solved by combining phosphoric acid concentration in the anode chamber 7 with evaporative concentration, but heating the liquid in the anode chamber 7 reduces the function of the diaphragm 8, causing hydrogen ions to flow from the anode chamber 7 to the cathode chamber 6. If evaporation and concentration are used together, the reverse extraction liquid 22 to be injected into the anode chamber 7 must be concentrated in advance, or the liquid in the anode chamber 7 can be sent to an evaporator to remove the liquid. The concentrated and cooled concentrate must be received in the anode chamber 7. FIG. 4 shows an example in which evaporative concentration is used in conjunction with phosphoric acid concentration in the back extraction liquid 22, in which the back extraction liquid 22 discharged from the separation tanks 12 and 33 to the receiving tank 50 is sent to the vapor compression type concentrator 51 to phosphoric acid. Concentrate the acid. The condenser 52 uses a container or pipe with a glass lining on the inside, and the compressor 53 sucks in steam to reduce the pressure inside the vessel.At the same time, the sucked vapor is compressed and the heat of compression is transferred to a jacket 54 or a heat exchanger tube or the like with a glass lining on the outside. Since the reverse extraction liquid 22 is evaporated and concentrated at a low temperature by being transferred to the liquid in the vessel, the energy consumption for evaporation and concentration is small, and neither a heat source nor cooling water is required. The concentrated liquid in the container is sucked by the pump 55 and sent to the anode chamber 7, and the condensed water is sent to the water storage tank 19 and used for circulation as back extraction water. In this way, by combining evaporative concentration with phosphoric acid concentration of the back extraction solution 22, the extra power consumption for water electrolysis is reduced in the process of electrodeposition regeneration, and sufficient back extraction water is used to achieve a more complete process. Since extraction and back extraction are possible, the speed or throughput of electrodeposition regeneration can be further improved. In order to confirm the effectiveness of phosphoric acid extraction and back extraction in the method of the present invention, 75% phosphoric acid was used as the electrolyte.
Using the used electrolyte that destained the SUS304 plate and tributyl phosphate (TBP) as the solvent,
The following extraction and back-extraction tests were performed. Add 40c.c. of TBP to 10c.c. of the above electrolyte to extract phosphoric acid in the electrolyte, and add water to the TBP from which the phosphoric acid has been extracted.
50c.c. is added to back-extract phosphoric acid, and 10c.c. of the above electrolyte is added again to the TBP regenerated by phosphoric acid back-extraction. Repeating the extraction and back-extraction operations yields 10c.c. of electrolyte. is reduced to 7 c.c. as phosphoric acid is extracted, and when 50 c.c. of water is added to TBP43 c.c. from which phosphoric acid has been extracted and phosphoric acid is back-extracted, the regenerated TBP returns to the initial 40 c.c. , 53 c.c. of back extract containing phosphoric acid can be obtained. The electrolyte A10c.c. used, and the second and fifth
Extracted liquid obtained from the second extraction and back extraction operation
The components contained in B7c.c., reverse extract C53c.c., and recycled TBPD40c.c. are shown in the table below.
【表】
この表から明らかなように、75%リン酸の除染
電解液を4倍の再生TBPでリン酸抽出し、リン
酸抽出後のTBPをほぼ同量の水で逆抽出すると、
電解液中のリン酸の1/2以上が逆抽出液に移行し、
TBPはほぼ完全に再生される。
このようにして得た抽出分離液と逆抽出液をそ
れぞれ電着再生槽の陰極室と陽極室に送つて電着
再生処理を行なうと、前記先願の方法と比較して
2倍以上の処理能力が得られる。
以上に述べたように、本発明の方法によると、
電着再生処理に供する電解液中のリン酸を抽出、
逆抽出操作により前もつて電着再生槽の陽極室側
に移行させるので、電着再生時間の短縮あるいは
電着再生処理量の増大をはかることができ、電解
液および溶媒を再生して繰返し使用できるので、
再汚染防止効果の高いリン酸系の高濃度酸電解液
を使用する電解除染工程における廃液処理の問題
が解消され、放射性二次廃棄物量の大幅な低減を
計ることができる。[Table] As is clear from this table, when a 75% phosphoric acid decontamination electrolyte is extracted with phosphoric acid using 4 times the amount of recycled TBP, and the TBP after phosphoric acid extraction is back-extracted with approximately the same amount of water,
More than 1/2 of the phosphoric acid in the electrolyte is transferred to the back extraction solution,
TBP is almost completely regenerated. When the extracted separated liquid and reverse extracted liquid obtained in this way are sent to the cathode chamber and the anode chamber of the electrodeposition regeneration tank and subjected to electrodeposition regeneration treatment, the processing time is more than twice that of the method of the previous application. ability is obtained. As described above, according to the method of the present invention,
Extracts phosphoric acid from electrolyte solution for electrodeposition regeneration treatment,
By back-extracting the electrolyte beforehand, it is transferred to the anode chamber side of the electrodeposition regeneration tank, which can shorten the electrodeposition regeneration time or increase the amount of electrodeposition regeneration throughput.The electrolyte and solvent can be regenerated and used repeatedly. Because you can
This solves the problem of wastewater treatment in the electrolytic dedying process, which uses a highly concentrated phosphoric acid electrolyte that is highly effective in preventing recontamination, and allows for a significant reduction in the amount of radioactive secondary waste.
第1図は本発明の1実施例の電着再生過程のフ
ローシート、第2図イは抽出分離槽での第1段
階、第2図ロはその第2段階、第2図ハはその第
3段階、第2図ニはその第4段階、第3図は本発
明の他の実施例の電着再生過程のフローシート、
第4図は蒸発濃縮を併用する場合のその部分のフ
ローシートである。
1…電解除染槽、2…被除染物、3…陰極、4
…ポンプ、5…電着再生槽、6…陰極室、7…陽
極室、8…隔膜、9…捕集電極、10…不溶性電
極、11…ポンプ、12…抽出分離槽、13…除
染電解液、14…撹拌機、15…抽出分離液、1
6…排出弁、17…電気電導度計、18…給水
弁、19…貯水槽、20…給水弁、21…逆抽出
用水、22…逆抽出液、23…排出弁、24…給
水弁、25…給水弁、26…ポンプ、30…抽出
槽、31…抽水液分離槽、32…逆抽出槽、33
…逆抽出液分離槽、34…ポンプ、35…撹拌
機、36…撹拌機、37…供給弁、38…供給
弁、39…ポンプ、40…給水弁、41…弁、5
0…受槽、51…蒸発濃縮装置、52…濃縮器、
53…圧縮機、54…ジヤケツト、55…ポン
プ、S…溶媒。
Figure 1 is a flow sheet of the electrodeposition regeneration process in one embodiment of the present invention, Figure 2 A is the first stage in the extraction separation tank, Figure 2 B is the second stage, and Figure 2 C is the second stage. 3 stages, FIG. 2 D is the fourth stage, and FIG. 3 is a flow sheet of the electrodeposition regeneration process of another embodiment of the present invention.
FIG. 4 is a flow sheet for the case where evaporation and concentration are used together. 1... Electrode-dye tank, 2... Decontaminated object, 3... Cathode, 4
... Pump, 5... Electrodeposition regeneration tank, 6... Cathode chamber, 7... Anode chamber, 8... Diaphragm, 9... Collection electrode, 10... Insoluble electrode, 11... Pump, 12... Extraction separation tank, 13... Decontamination electrolysis Liquid, 14... Stirrer, 15... Extraction separation liquid, 1
6... Discharge valve, 17... Electrical conductivity meter, 18... Water supply valve, 19... Water tank, 20... Water supply valve, 21... Water for back extraction, 22... Back extraction liquid, 23... Discharge valve, 24... Water supply valve, 25 ...Water supply valve, 26...Pump, 30...Extraction tank, 31...Water extraction liquid separation tank, 32...Back extraction tank, 33
... Reverse extraction liquid separation tank, 34 ... Pump, 35 ... Stirrer, 36 ... Stirrer, 37 ... Supply valve, 38 ... Supply valve, 39 ... Pump, 40 ... Water supply valve, 41 ... Valve, 5
0... Receiving tank, 51... Evaporation concentration device, 52... Concentrator,
53... Compressor, 54... Jacket, 55... Pump, S... Solvent.
Claims (1)
の高濃度酸除染電解液を隔膜電解によつて電着再
生する方法において、電着再生処理に供する除染
電解液から溶媒でリン酸を抽出してその抽出分離
液を隔膜で仕切つた電着再生槽の陰極室に送り、
リン酸を抽出した溶媒から水でリン酸を逆抽出し
てその逆抽出液を隔膜で仕切つた電着再生槽の陽
極室に送り、陰極室の捕集電極と陽極室の不溶性
電極との間に直流通電して陰極室で液中の金属イ
オンを電着捕集するとともに、陽極室で初期の電
解液濃度にまでリン酸液を濃縮し除染電解液とし
て再使用することを特徴とするリン酸系除染電解
液の電着再生方法。 2 リン酸抽出用溶媒としてリン酸トリブチルを
使用する特許請求の範囲第1項記載の方法。 3 電着再生終了後の陰極室液を逆抽出用水とし
て循環使用する特許請求の範囲第1項記載の方
法。 4 逆抽出液のリン酸濃縮に蒸発濃縮を併用する
特許請求の範囲第1項記載の方法。[Scope of Claims] 1. In a method for electrodepositing and regenerating a phosphoric acid-based high-concentration acid decontamination electrolyte solution used for electrolytic removal of radioactive contaminants by diaphragm electrolysis, a decontamination electrolyte to be subjected to electrodeposition regeneration treatment. Phosphoric acid is extracted from the liquid using a solvent, and the extracted and separated liquid is sent to the cathode chamber of an electrodeposition regeneration tank separated by a diaphragm.
Phosphoric acid is back-extracted with water from the solvent used to extract phosphoric acid, and the back-extracted liquid is sent to the anode chamber of the electrodeposition regeneration tank, which is separated by a diaphragm, between the collection electrode in the cathode chamber and the insoluble electrode in the anode chamber. The method is characterized in that metal ions in the solution are electrodeposited and collected in the cathode chamber by applying direct current to the phosphoric acid solution, and the phosphoric acid solution is concentrated to the initial electrolyte concentration in the anode chamber and reused as a decontamination electrolyte. Electrodeposition regeneration method of phosphoric acid decontamination electrolyte. 2. The method according to claim 1, wherein tributyl phosphate is used as the solvent for extracting phosphoric acid. 3. The method according to claim 1, wherein the cathode chamber liquid after completion of electrodeposition regeneration is recycled as water for back extraction. 4. The method according to claim 1, in which evaporative concentration is used in combination with phosphoric acid concentration of the back extract.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11784784A JPS60260899A (en) | 1984-06-07 | 1984-06-07 | Electrodeposition regeneration method of phosphoric acid group decontamination electrolyte |
US06/661,696 US4615776A (en) | 1983-10-21 | 1984-10-17 | Electrolytic decontamination process and process for reproducing decontaminating electrolyte by electrodeposition and apparatuses therefore |
EP84307185A EP0141590B1 (en) | 1983-10-21 | 1984-10-18 | Method and apparatus for regenerating an acid electrolyte that has been used in the decontamination of components with radioactively contaminated surfaces |
DE8484307185T DE3484045D1 (en) | 1983-10-21 | 1984-10-18 | METHOD AND ARRANGEMENT FOR REGENERATING AN ACID ELECTROLYTE USED FOR DECONTAMINATING COMPONENTS WITH RADIOACTIVELY CONTAMINATED SURFACES. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11784784A JPS60260899A (en) | 1984-06-07 | 1984-06-07 | Electrodeposition regeneration method of phosphoric acid group decontamination electrolyte |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60260899A JPS60260899A (en) | 1985-12-24 |
JPH0324997B2 true JPH0324997B2 (en) | 1991-04-04 |
Family
ID=14721742
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11784784A Granted JPS60260899A (en) | 1983-10-21 | 1984-06-07 | Electrodeposition regeneration method of phosphoric acid group decontamination electrolyte |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS60260899A (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6450998A (en) * | 1987-08-21 | 1989-02-27 | Power Reactor & Nuclear Fuel | Electrolysis treating method of radioactive waste liquid |
JP4855330B2 (en) * | 2007-05-08 | 2012-01-18 | 日本バルカー工業株式会社 | Method for regenerating phosphoric acid-containing treatment solution |
-
1984
- 1984-06-07 JP JP11784784A patent/JPS60260899A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS60260899A (en) | 1985-12-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0141590B1 (en) | Method and apparatus for regenerating an acid electrolyte that has been used in the decontamination of components with radioactively contaminated surfaces | |
US5078842A (en) | Process for removing radioactive burden from spent nuclear reactor decontamination solutions using electrochemical ion exchange | |
JPH0324997B2 (en) | ||
JP2509654B2 (en) | Chemical decontamination waste liquid treatment method | |
JPS61231496A (en) | Method of decontaminating radioactive metallic waste | |
JPH11237495A (en) | Processing method for radioactive waste liquid and its device | |
JPH0557560B2 (en) | ||
JPH0443239B2 (en) | ||
JPS61161500A (en) | Electrolytic decontamination waste liquor treating method | |
RU2713733C1 (en) | Method for decontamination of graphite radioactive wastes | |
KR101292373B1 (en) | Electrochemical decontaminating system of radioactive metal waste and the system using the same | |
JPS603593A (en) | Method of electrolytically decontaminating radioactive metallic waste | |
JPS62130396A (en) | Method of removing oxide film containing radioactive substance | |
RU2110860C1 (en) | Decontaminating process for multiple forced circulation loop of water-graphite reactors | |
JPS5915900A (en) | Method of decontaminating radioactive metal waste | |
JPS61231498A (en) | Method of electrolytically decontaminating radioactive metallic waste | |
JPS6113198A (en) | Method of decontaminating waste-liquor evaporator | |
JPS604895A (en) | Electrolytic decontaminating waste liquor regenerating treating device | |
JPS59163600A (en) | Electrolysis decontamination liquid waste recovering device | |
JPS59120900A (en) | Electrolytic removal method and apparatus for radioactive pollutant | |
JPS604899A (en) | Decontaminating device | |
JPS6275389A (en) | Melter for spent nuclear fuel | |
JPH031639B2 (en) | ||
JPS59219499A (en) | Electrolytic decontaminating method by dilute electrolyte | |
JPH05323095A (en) | Processing method for decontamination waste liquid |