P538纸上萃取色层法分离稀土元素及萃取机理的研究

STUDY ON THE SEPARATION AND THE EXTRACTION MECHANISM OF RE ELEMENTS BY MEANS OF REVERSED-PHASE PAPER CHROMATOGRAPHY

研究了以P538为固定相,用不同浓度的无机酸或无机酸与其盐的混合溶液作展开剂进行反相纸层析时对稀土R_F值的影响。实验表明,所得的R_F值对稀土元素的原子序数作图时,有明显的四分组效应。根据同一元素在不同酸中的R_F值的顺序,可知在不同的无机酸中,P538对稀土的萃取能力顺序为:HCl>HNO_3>H_2SO_4。稀土元素与P538反应时的摩尔比及释放出的氢离子数分别为1和3。萃取温度对稀土元素的R_F值无显著影响;重稀土组的分离系数(β_Z^(Z+1))比轻稀土组大,因而P538纸层析可将重稀土(Ho～Lu)相互分离。

Reversed-phase paper chromatography technique was used for study on the extraction mechanism and separation of RE elements. As the stationary phase, chromatographic paper strips were impregnated with a solution of the monomyristylphosphoric acid (P538) in chloroform. Mineral acids were used as developers.The effect of various concentrations of acids or acids and salts upon R_F has been investigated, according to the order of R_F values of the same element in various acids, the order of RE extraction ability is: HCl>HNO_3>H_2SO_4·A tetrad effect is observed clearly between RF found and the atomic number off RE elements. The effects of other parameters on the R_F value, such as the quantities of the extractant retained by the paper and the temperature of development were also examined. The molar ratio of P538 to RE and the number of H^+ ion liberated in this extraction reaction were determined. Based on this experiment resuit, a reasonable equation was suggested.According to the separation coefficient β_Z^(Z+1), the separation of heavy RE each other will be more easily than light RE because the separation coefficient of the former is larger than of the later. The separation of a mixture of Ho-Er-Tm-Yb-Lu were carried out by the present method with success.