Separation of rare earth elements from scandium by extraction chromatography Application to radiochemical neutron activation analysis for trace rare earth elements in geological samples

摘要

An effective and practical radiochemical separation procedure of radiochemical neutron activation analysis(RNAA)for ultra trace rare earth elements(REEs)in silicate rock samples is presented.The procedure consists of two column separations of anion exchange and extraction chromatography and precipitation as hydroxide and fluoride of REEs.The most seriously interfering nuclide,~46Sc,is completely separated(<0.005%)from REEs by extraction chromatography using transuranic-element specific(TRU,Spec)resin.Chemical yields were determined by inductively coupled plasma atomic emission spectrometry(ICP-AES)and found to be constant within 3% for all REEs,implying that no fractionation occurs among REEs during the rediochemical purification procedure.By means of this procedure,other interfering nuclides than ~46Sc in RNAA of silicate samples were decreased down to <0.02% for ~59Fe,<0.006% for ~60Co and <0.000005% for ~51Cr.The RNAA procedure described in this paper can be one of the most suitable analytical procedures for accurately determining ultra-trace(1-10 pg)REEs in geological and cosmochemical sampoles.