Equilibrium of Nitrous Acid-Catalyzed Oxidation of Neptunium in Nitric Acid-TBP Extraction System

この論文にアクセスする

この論文をさがす

著者

    • TOCHIYAMA Osamu
    • Department of Nuclear Engineering, Faculty of Engineering, Tohoku University
    • KATAYAMA Yasushi
    • Department of Nuclear Engineering, Faculty of Engineering, Tohoku University
    • INOUE Yasushi
    • Department of Nuclear Engineering, Faculty of Engineering, Tohoku University

抄録

The redox equilibrium of neptunium with nitric and nitrous acids, <BR>NpO<SUB>2</SUB><SUP>+</SUP>+(3/2)H<SUP>+</SUP>+(1/2)NO<SUB>3</SUB><SUP>-</SUP>=NpO<SUB>2</SUB><SUP>2+</SUP>+(1/2)HNO<SUB>2</SUB>+(1/2)H<SUB>2</SUB>O<BR>was studied in 3 to 6M nitric acid solutions by 30vol% TBP-dodecane extraction. The equilibrium distribution ratio of neptunium was shown to be expressed by D=D<SUB>6</SUB>R/(1+R), where R is [Np(VI)]/[Np(V)] and D<SUB>6</SUB> the distribution ratio of pure Np(VI). To examine the dependence of the apparent concentration constant for the reaction, <BR>K<SUB>app</SUB>=[NP(VI)][HNO<SUB>2</SUB>]<SUP>1/2</SUP>/[Np(V)][HNO<SUB>3</SUB>]<SUB>t</SUB><SUP>2</SUP><BR>on nitric acid concentration, the redox potentials of HNO<SUB>3</SUB>/HNO<SUB>2</SUB> solutions were measured which revealed that the activity correction on H<SUP>+</SUP>, NO<SUB>3</SUB><SUP>-</SUP>, HNO<SUB>2</SUB> and H<SUB>2</SUB>O was effective enough to give an ideal Nernst relationship for the potential of HNO<SUB>3</SUB>/HNO<SUB>2</SUB>. With using the activity coefficient quotient, Y=y<SUB>S</SUB><SUP>2</SUP>/(y<SUB>u</SUB>a<SUB>w</SUB>)<SUP>1/2</SUP>(y<SUB>S</SUB>: stoichiometric activity coefficient of nitric acid, y<SUB>u</SUB>: activity coefficient of HNO<SUB>2</SUB>, a<SUB>w</SUB>: rational activity of water), the apparent concentration constant K<SUB>app</SUB> was shown to be expressed by K<SUB>app</SUB>=K<SUB>mix</SUB>Y, where <BR>K<SUB>mix</SUB>=[Np(VI)]{HNO<SUB>2</SUB>}<SUP>1/2</SUP>{H<SUB>2</SUB>O}<SUP>1/2</SUP>/[NP(V)]{H<SUP>+</SUP>}<SUP>3/2</SUP>{NO<SUB>3</SUB><SUP>-</SUP>}<SUP>1/2</SUP><BR>and log K<SUB>mix</SUB>=-2.77 and log Y=-0.13, 0.02 and 0.28 for [HNO<SUB>3</SUB>]<SUB>t</SUB>=3, 4 and 6M, respectively.

収録刊行物

  • Journal of nuclear science and technology  

    Journal of nuclear science and technology 32(1), 50-59, 1995-01-25 

    Atomic Energy Society of Japan

参考文献:  22件

参考文献を見るにはログインが必要です。ユーザIDをお持ちでない方は新規登録してください。

被引用文献:  3件

被引用文献を見るにはログインが必要です。ユーザIDをお持ちでない方は新規登録してください。

各種コード

  • NII論文ID(NAID)
    10002071908
  • NII書誌ID(NCID)
    AA00703720
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    00223131
  • データ提供元
    CJP書誌  CJP引用  J-STAGE 
ページトップへ