Neutron activation analysis of microgram amounts of thorium in uranium ores and process liquors by means of thorium-233

lonium and Thorium Balance in Uranium Mills

“…The ionium and thorium Contents of the soUd suspended in the samples 5, 6 and 7 have been neglected in Tables 3 and 4 because their contribution to the assay of the respective liquid phases is very low, as it may be seen in Table 5 where they are referred to the liquid volume; ionium data have been obtained by extraction with TTA [14] and ion exchange [16], and thorium results by neutron activation [19,20]. Ionium and thorium distribution along the diiFerent steps in the uranium miU can be seen in Table 6; in both cases data for sample 6 have been used to evaluate the total amount in ion exchange effluent.…”

“…München's method for simultaneous assay of ionium and thorium [13]: The Ti/Th precipitate obtained as described in 2.1. is irradiated together with a thorium Standard; ^sapg, activity of both samples is measured and compared. JEN's method by neutron activation [19,20]: The neutron irradiated sample is melted with Na202 flux in a Parr's bomb; the melt is leached with water containing thorium carrier and the hydroxides precipitate is dissolved in conc. HCl; the Solution is passed through an anion exchange bed and ThF4 is precipitated from the column effluent.…”

Ion-exchange chromatography

“…The prediction in the 1966 review that high-resolution gamma-ray spectrometers would decrease the need for chemical separations in neutron activation analysis does not seem to have been fulfilled. Separations by ion exchange have followed activation in the analysis of rocks (62,63,159,349) and meteorites (116,174,317). Trace elements thus determined include chromium (62), copper, gallium and zinc (63), rhenium (159), antimony and tin (174) and mercury (116,174).…”