HNO_3介质中TiAP萃取Th(Ⅳ)的动力学研究

Kinetics of solvent extraction of Th(Ⅳ)with TiAP in nitric acid solution

本文以恒界面池法研究了HNO3介质中TiAP对Th(Ⅳ)的萃取动力学性质.在一定条件下,考察了萃取时间对萃取率的影响,并测定了搅拌速度、温度、界面积以及各反应物初始浓度对萃取速率的影响.实验结果表明:萃取体系在约6h后达到平衡;搅拌速度(120-180rpm)对萃取速率无显著影响,萃取反应的活化能为23.20kJ/mol,萃取过程为界面反应的混合控制模型.在HNO3介质中,TiAP萃取Th(Ⅳ)的化学反应速率方程为:r=-dcTh(NO3)4/dt=k[Th(NO3)4]1.05[TiAP]1.77[HNO3]0.38,其中,k=1.6×10-2(mol/L)-2.2·s-1.

The kinetics of solvent extraction of Th（Ⅳ） from 2 mol/L of HNO3 solution with triisoamyl phosphate（TiAP）-kerosene（KO） was investigated in Lewis cell. The results show that the extraction of Th（Ⅳ） takes place at the liquid-liquid interface, while the process of this extraction is one kind of the mixed controlled system with the activation energy of about 36.35 kJ/mol. And the reaction rate expres- sion has been obtained as. r= -dcTh（NO3 ）4/dt=k[Th（NO3 ）4]^1.05 [TiAP]^1.77 [-HNO310.38 , where, k= 1.6× 10^-2（mol/L）^-22 . s^-1.