硝酸体系中Cyanex923萃取La(Ⅲ)性能研究

Study on Extraction Performance of Cyanex923 for Lanthanum(Ⅲ) in Nitrate Medium

研究了硝酸体系中中性萃取剂Cyanex923(三烷基氧膦混合物)对轻稀土元素La(Ⅲ)的萃取性能。考察了金属离子、Cyanex923及硝酸根的浓度对La(Ⅲ)萃取的影响,由斜率分析法确定了反应机理,得出萃取平衡方程。探讨了温度对Cyanex923萃取La(Ⅲ)的影响,由Van′t Hoff方程计算出温度范围在298～323 K之间的热力学参数值△H、△S和△G。反萃实验发现,当硝酸浓度>1.0 mol.L-1时,负载La(Ⅲ)的Cyanex923的反萃率可达100%。

In the present work,the extraction performance of neutral extractant Cyanex923（a mixture of straight chain triakylphosphine oxide） for light rare earth La（Ⅲ） had been investigated.The effects of La（Ⅲ）,Cyanex923 and NO-3 concentration on La（Ⅲ） extraction were studied,respectively.The extraction mechanism was suggested based on the slope analysis and the extraction equilibrium equation was obtained.The effect of temperature on La（Ⅲ） extraction was investigated.From the temperature dependent data,the thermodynamic parameter values（△H,△S and △G） were calculated by Van′t Hoff equation during temperature of 298 K to 323 K.The stripping behavior of loaded Cyanex923 was investigated by nitric acid of different concentrations.It was found that when nitric acid concentration was more than 1.0 mol·L^-1,the stripping rate could rech 100%.