测定稀土化合物中的杂质钍时.经常采用萃取-比色法。钍的浓缩常采用Д_2ЗТФК~*-ТБФ四氯化碳混合溶液、丙酮-醋酸乙酯混合物及异丁醚苯溶液进行萃取的方法。最后用偶氮胂Ⅲ或钍试剂光度法测定钍。该法对于分离钍与钇组稀土无效。因为随着基体元素原子序 Determination of impurities in rare earth compounds thorium often use extraction - colorimetric method. Thorium enrichment often Д_2ЗТФК ~ * -ТБФ carbon tetrachloride mixed solution, acetone - ethyl acetate mixture and isobutyl ether benzene solution extraction method. Finally, arsenazo Ⅲ or thorium reagent photometric method for the determination of thorium. The method for separating thorium and yttrium rare earth invalid. Because with the matrix element atomic order