摘要
从Np(Ⅴ,Ⅵ)与二甲基羟胺(DMHAN)、单甲基肼(MMH)反应动力学及有机相中Np(Ⅵ)的反萃动力学两方面实验考察了APOR流程1B槽中镎的走向行为。结果表明:DMHAN还原Np(Ⅵ)的速率很快,动力学方程为-dc(Np(Ⅵ))/dt=kc(Np(Ⅵ))c(DMHAN)/c0.6(H+),25℃时,反应速率常数k=289.8(mol·L-1)-0.4·min-1;进一步还原Np(Ⅴ)的速率则很慢,其中,DMHAN还原Np(Ⅴ)的动力学方程为-dc(Np(Ⅴ))/dt=kc(Np(Ⅴ))c(DMHAN)c(H+),25℃时,k=0.0236(mol·L-1)-2·min-1;MMH还原Np(Ⅴ)的动力学方程为-dc(Np(Ⅴ))/dt=kc(Np(Ⅴ))c0.36(MMH)c(H+),25℃时,k=0.0022(mol·L-1)-1.36·min-1。所以,1B槽中Np主要以Np(Ⅴ)形式存在。在扩散控制模式下,DMHAN和MMH对Np(Ⅵ)的反萃动力学方程分别为:dca(Np(Ⅵ))/dt=k(V/S)co0.,05(Np(Ⅵ)).co-0.14(TBP)ca-0.32(NO3-),25℃时,k=2.29×10-4(mol·L-1)0.96·cm-1·min-1;dca(Np(Ⅵ))/dt=k(V/S)co0.,063(Np(Ⅵ))co-0.27(TBP)ca-0.34(NO3-),25℃时,k=6.24×10-4(mol·L-1)0.98·cm-1·min-1。可见,DMHAN-MMH存在下,Np可被快速反萃入水相。基于以上的动力学参数以及工艺过程参数,可计算出1B槽中95%的Np进入水相。
In order to explain the distribution of neptunium in 1B contactor, the kinetics of reaction between Np(Ⅵ ) and dimethylhyoxylamine (DMHAN) as well as Np (V) and DMHAN, Np(V) and methylhydrazine (MMH) was studied. The reaction rate is much faster between Np (VI) and DMHAN/MMH than that between Np (V) and DMHAN/MMH. The rate equation of the reaction between Np(VI) and DMHAN is obtained as --dc(Np(Vi))/dt=kc(Np(gI))c(DMHAN)/c0.6 (H+ ), and the apparent k is 289.8 (mol/L)-0.4 · min 1 at 25 ℃. The rate equation of the reaction between Np(V) and DMHAN is --dc(Np(V))/dt=kc(Np(V))c(DMHAN)c(H+), and k is 0. 023 6 (mol/L) 2 . min-1 at 25 ℃. The rate equation of the reaction between Np(V ) and MMH is -- dc (Np (V))/dt = kc (Np (V)) c0.36 (MMH) c (H+), and k is 0. 002 2 (mol/L)-1.36 min-1 at 25 ℃. When the process is controlled by diffusion, the stripping rate equation for Np from 30% TBP/OK by DMHAN is obtained as --dc(Np(VI))/dt=k(V/S)c0,0 (Np (Ⅵ) co--0.14 (TBP) co-0.322 (NO3-), k is 2.29 × 10-4 (mol/L)0.96 · cm-1 . min-1 at 25 ℃, and --dc(Np(VI))/dt=k(V/S)co3 (Np(gl)) · c2.27(TBP)co-0.34(N03), k is 6.24×10-4 (mol/L)0.98 · cm-1· min-1 at 25 ℃. Based on these kinetic parameters, the stripping efficiency of Np in 1B contactor is calculated as 95%.
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2010年第2期129-137,共9页
Atomic Energy Science and Technology
关键词
镎
二甲基羟胺
单甲基肼
动力学
还原反萃
neptunium
dimethylhyoxylamine
methylhydrazine
kinetics
reduction reextraction