Quantitative Analysis of Thorium Containing Materials Using Industrial XRF Analyser

The potential applicability of X-ray fluorescence (XRF) industrial conveyor analyser CON-X series is discussed for thorium (Th) quantitative or semi-quantitative on-line measurement in different types of Th-bearing materials. Laboratory study of several minerals (heavy mineral sands and carbonate rocks as unconventional Th resources; monazite concentrate as Th-associated resources and uranium ore residues after heap-leaching as a waste product) was performed and analyser was tested for on-line quantitative measurements of Th contents along with other major and minor components. The Th concentration range in raw heavy mineral sand is 50–600 ppm; its minimal detection limit (MDL) at this level is estimated at 25–50 ppm in 5-minute measurements depending on the type of material. On-site test of the CON-X analyser for continuous analysis of thorium traces along with other elements in zircon sand showed that accuracy of Th measurements is within 20% relative. When Th content is higher than 1% as in the concentrate of monazite ore (5–8 % ThO₂) accuracy of Th determination is within 1% relative. (author)