岩石中钍及稀土的萃取色层分离和分光光度测定法研究

STUDIES ON EXTRACTIVE CHROMATOGRAPHIC SEPARATION AND SPECTROPHOTOMETRIC DETERMINATION OF TH AND REE IN ROCKS

本文试验研究了以硅烷化多孔微球硅胶为担体,P507为固定相,盐酸和硫酸作流动相,在小色层柱上分离稀土和钍的最佳条件。并进一步对偶氮胂Ⅲ与稀土和钍在水-乙醇体系当中的显色反应条件进行了研究。将该法应用于岩石中稀土总量和钍的连续测定,结果良好。

In this paper the chromatographic behaviour of Th and the condition of the extractive chromatographic separation on REE and Th have been systematically studied in a small chro- matographic column,with P507 as stationary phase and silanization porous mocrobeads siiica gel as supporter.When the column temperature is 30℃,REE and Th can be completely separar- ed by elution,using 20 ml of 4 mol/L hydrochloric aicid and 30 ml of 2 mol/L sulphuric acid, respectly.A rapid spectrophotometric method for the determination of REE and Th in rocks has been thus established.The sensitivity and stability are markedly increased by the addition of alcohol in the REE (Th)-Arsenazo Ⅲ system.For the REE-Arsenazo Ⅲ-alcohol system, the molar absorptivity is about twice as large as before,and for another system,Th—arsenazo Ⅲ—alcohol,the molar absorptivity is found to be 140000 L·mol^(-1)cm^(-1).The absorbance of these two systems may be keep for 24 hours. This method has been used to determine trace amount of Th and total amount of REE in standard samples of rock (GSR),giving a good agreernent with the certified value.