MULTIELEMENT CHARACTERIZATION OF HIGH-PURITY TITANIUM-DIOXIDE BY NEUTRON-ACTIVATION ANALYSIS

A radiochemical neutron activation analysis method for the determinati on of 34 elements in titanium dioxide has been developed. For the assa y of indicator radionuclides with short and with long half-lives, the radiochemical separation was performed by anion exchange on a Dowex 1 x 8 column and by combination of cation and anion exchange on a Dowex 50W x 8 and a Dowex 1 x 8 column from HF-and HF/NH4F-medium, respectiv ely. With both separation modes, a selective removal of the matrix-pro duced radionuclides Sc-46, Sc-47 and Sc-48 was achieved. A selective e xtraction of copper with dithizone from 15 mol/L HF enabled counting t he intensive but unspecific 511-keV rays of Cu-64 for the determinatio n of Cu. The limits of detection achieved were between 0.004 ng/g for Sm and 0.8 mu g/g for Sn (via Sb-125). The elements La, Mn and Th were determined by instrumental neutron activation analysis only. These te chniques were applied to the analysis of two titanium dioxide samples of different purity grade. The results and limits of detection are com pared with those of other methods.