The present study reports the likely first attempt of separating radioactive minerals for estimation of activity concentration in the beach placer sands of Bangladesh. Several sand samples from heavy mineral deposits located at the south-eastern coastal belt of Bangladesh were processed to physically upgrade their radioactivity concentrations using plant and laboratory equipment. Following some modified flow procedure, individual fractions were separated and investigated using gamma-ray spectrometry and powder-XRD analysis. The radioactivity measurements indicated contributions of the thorium and uranium radioactive series and of 40 K. The maximum values of 232 Th and 238 U, estimated from the radioactivity of 208 Tl and 234 Th in secular equilibrium, were found to be 152,000 and 63,300 Bq/kg, respectively. The fraction of the moderately conductive part in electric separation contained thorium predominantly, while that of the non-conductive part was found to be uranium rich. The present arrangement of the pilot plant cascade and the fine tuning of setting parameters were found to be effective and economic separation process of the radioactive minerals from placer sands in Bangladesh. Probable radiological impacts and extraction potentiality of such radioactive materials are also discussed.

Beach sands harbor appreciable amount of radioactive elements such as zircon which contains some important and radioactive elements (e.g. uranium, thorium). Very limited quantitative information is available of such elements in the sand of the beaches of Cox's Bazar in Bangladesh. The present study presents application of Neutron Activation Analysis (NAA) to quantify uranium and thorium elemental concentration in zircon assemblages from beach placers of Cox's Bazar. Zircon was separated from beach sands in a mineral processing pilot plant. The separated zircon assemblages were examined by a polarizing petrographic microscope and X-ray diffraction techniques and found that it contained more than 75% pure zircon. Thereafter, uranium and thorium concentrations in zircon were measured by NAA and revealed that zircon contained 94-141 ppm uranium and 127-506 ppm thorium. Therefore, this noticeable amount of uranium and thorium in zircon should be taken in consideration during any mining attempt of the placer minerals present in Cox's Bazar beaches.

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