摘 要：为解决高含量稀土和钍的分离问题对稀土产品中钍进行测定。该方法对比酒石酸、三乙醇胺的用量，设计分离富集工艺，采用743型大孔树脂分离稀土和钍，使用偶氮胂III比色法测定。试样经过碱熔，水浸取加入三乙醇胺，过滤。沉淀用盐酸（4 mol/L）溶解，在酒石酸存在下，用盐酸（4 mol/L）淋洗杂质，用氯化铵溶液（20%）将树脂转化为铵型后，再用草酸铵溶液（4%）洗脱钍。在盐酸（4 mol/L）介质中，用偶氮胂III显色于波长660 nm处测定。实验表明该方法操作简便，设备简单，结果稳定，精密度和准确度高。
中图分类号：TG146.4；TF125.2+4；O615.2；O633 文献标志码：A 文章编号：1674-5124（2013）05-0053-03
Determination of thorium in rare earth products
（Sichuan Radiation Detection and Protection Institute of Nuclear Industry，Chengdu 610503，China）
Abstract: In order to separate thorium from the high-content rare earth and determine thorium in rare earth products， the authors studied the impact of tartaric acid， triethanolamine at different dosage， designed the routing of extraction and enrichment with macroporous resin 743 as separation materials， and thorium contents was determined by arsenazo III colorimetric method. In this method， the sample was digested with alkaline solution， extracted with aqueous triethanolamine. After it was filtered， the precipitate was dissolved with 4 mol/L hydrochloric acid. In the presence of tartaric acid， the impurities of resin was eluted with 4 mol/L hydrochloric acid， and the resin was converted to ammonium resin with 20% ammonium chloride solution， then thorium was eluted with 4% ammonium oxalate solution. In 4 mol/L hydrochloric acid， the extract was reacted with arsenazo III， and measured at the wavelength of 660 nm. This method is easy in operation， simple in the requirement of equipments， and the measurement results is stable， precise and accurate.
Key words: rare earth product； thorium； 743 macroporous resin； arsenazo III； separation and enrichment