摘要
在振动搅拌槽中,研究了UO_2(NO_3)_2-HNO_3-N_2H_5NO_3(H_2O)/30％TBP(煤油)体系的水相电解液组分浓度对U(Ⅵ)电解还原速率的影响。根据实验数据,经回归分析得反应动力学微分方程: -(d[U(Ⅵ)]/dt)=k[U(Ⅵ)]^(0.77)[N_2H_5^+]^(0.061)[HNO_3]~0.017式中速度常数k是温度的函数。25℃时,k=0.0019。在实验浓度范围内,U(Ⅵ)还原速率随U(Ⅵ)浓度升高而增大,表现反应级数为0.75级,而[N_2H_5^+]及[HNO_3]影响很小,反应级数近于0。初步探讨了硝酸的电解还原以及硝酸肼对其还原过程的抑制作用,给出了不同硝酸浓度下的极化曲线。对于硝酸电解还原过程中主要产物亚硝酸的生成量与硝酸浓度、电解时间及肼浓度等的关系进行了讨论。
Ina study for the development of iu-situ uranium and plutonium electro-reduction process and equipment, the dependence of U(Ⅵ) electro-reduction rates on component concentrations has been investigated with the system UO_2 (NO_3)_3-HNO_3-N_2H_5NO_3 (H_2O)/30％TBP (OK).The electrolytic cell employed is a gless column with an internal diameter of 50mm. The sieve plates care made of titanium, serving as cathode, the anodical central rod is madse of platinum or stainless steel, and polyethylene material is used for the insulators between anode and cathode. The Oscillation of reciprocating plate makes both phases dispersed. The U(Ⅵ)famrotion rates are measured under various component concentrations.
The results show that the presence of hydrazine as the supporting reductant or stabilizer is necessary for the reduction of U(Ⅵ). In the range of experimental concentrations, the U(Ⅵ) reduction rates are mainly dependent on the U(Ⅵ)eoncentration in the system and slightly dependent on the [HNO_3] and[N_2H_5^+]concentrations. The data for the preset system are well correlated by the following rate equation:
-d[U(Ⅵ)]/dt=k[U(Ⅵ)]^(0.77)[N_2H_5^+]^(0.061)[HNO_3]^(0.017)here the rate constant k is a function of temperature, k=0.0019 at t=25℃
出处
《核科学与工程》
CSCD
北大核心
1992年第1期66-75,86,共11页
Nuclear Science and Engineering
