DETERMINATION OF RARE EARTH ELEMENTS IN GEOLOGICAL SAMPLE BY PRE-GROUP SEPARATION ON-NEUTRON ACTIVATION ANALYSIS

Thirteen rare earth elements in geological sample are determined by neutronactivation analysis. The sample is decomposed by acid. The interfernceelements such as Fe, Sc, Cr, U and Th are removed by Topo-cyclohexaneextraction. The rare earth elements are separated and concentrated by passingthrough D_2EHPA-Kel-F Column. After irradiating the concentrate in reactor for20 hours and waiting for some time, the γ-spectra of activated rare earth elementsare measured by program control Ge (Li) γ-spectrometer. The precision of methodless than ±15%. The recovery of the separation process is more than 90%.