Np(Ⅳ,Ⅴ,Ⅵ)在稀TBP/煤油与水相间的分配  

Distribution of Np(Ⅳ,Ⅴ,Ⅵ) Between Dilute TBP/Kerosene and Aqueous Phase

作　　者：贾永芬[1] 朱志瑄[1] 罗方祥[1] 胡景炘[1] 叶国安[1] 

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《原子能科学技术》2001年第2期97-103,共7页Atomic Energy Science and Technology

摘　　要：在制备并稳定Np(Ⅳ )、Np(Ⅴ )、Np(Ⅵ )的基础上 ,研究了它们在稀TBP/煤油与水相间的分配。考察了 2 5℃下 5%TBP/煤油萃取时硝酸浓度、硝酸铝浓度、六价铀浓度对 3种价态镎萃取分配的影响 ,并考察了TBP浓度对它们的萃取影响。 2 5℃下 ,Np(Ⅳ ,Ⅴ ,Ⅵ )的萃取反应方程及表观平衡常数分别为 :Np4 ++4NO- 3 +2TBPNp(NO3) 4 ·2TBP ,Kex(Np(Ⅳ ) ) =0 .70 5mol- 6·L6;NpO+2 +NO- 3 +TBPNpO2 NO3·TBP ,Kex(Np(Ⅴ ) ) =0 .0 378mol- 2 ·L2 ;NpO2 +2 +2NO- 3 +TBPNpO2 (NO3) 2 ·TBP ,Kex(Np(Ⅵ ) ) =2 .15mol- 3·L3。在 2 5～ 50℃范围内求得这 3个萃取反应的焓变分别为ΔH(Np(Ⅳ ) ) =1.18kJ·mol- 1;ΔH(Np(Ⅴ ) ) =- 3.71kJ·mol- 1;ΔH(Np(Ⅵ ) ) =-2 .78kJ·mol- 1。On the base of the preparation and stabilization of Np(Ⅳ),Np(Ⅴ) and Np(Ⅵ), the distributions of them between dilute TBP/kerosene and aqueous phase are studied. The influences of the concentrations of nitric acid, aluminum nitrate and uranyl on the extraction of Np(Ⅳ,Ⅴ,Ⅵ) by 5 % TBP/kerosene are investigated at temperature of 25 ℃. The equations of extraction reactions at corresponding conditions are obtained. The influences of the concentration of TBP on the extraction of Np(Ⅳ,Ⅴ,Ⅵ) are studied, The extraction reaction equations of them and the corresponding apparent equilibrium constants at temperature of 25 ℃ are as follows: Np 4+ +4NO - 3+2TBPNp(NO 3) 4·2TBP, K ex (Np(Ⅳ))=0.705 mol -6 ·L 6;NpO + 2+ NO - 3+ TBPNpO 2NO 3·TBP, K ex (Np(Ⅴ))=0.0 378 mol -2 ·L 2;NpO 2+ 2+2NO - 3+TBP NpO 2(NO 3) 2 ·TBP, K ex (Np(Ⅵ))=2.15 mol -3 ·L 3, respectively. From 25 ℃ to 50 ℃, the enthalpy changes of the extraction reactions are as follows: Δ H (Np(Ⅳ)) =1.18 kJ/mol, Δ H (Np(Ⅴ)) =-3.71 kJ/mol and Δ H (Np(Ⅵ)) =-2.78 kJ/mol。

关 键 词：TBP 萃取 镎(Ⅳ) 镎(Ⅴ) 镎(Ⅵ) 煤油 水 相分配 平衡常数 乏燃料后处理 

分 类 号：TL241.14[核科学技术—核燃料循环与材料]