Radiochemical technique as a tool for determination and characterisation of El Sela ore grade uranium deposits

Abstract

ABSTRACT The present study is an application of a radiochemical procedure for the determination of 238U, 235U and 234U as well as uranium isotopic ratios in El Sela ore grade samples that located at the Southeastern Desert of Egypt. This procedure is consisting of several steps include sample preparation, chemical separation and source preparation followed by counting using alpha-particle spectrometry technique. Radiochemical determination of various uranium isotopes contents indicated that El Sela uranium deposits are considered as a recent deposit where there was a large difference between radiochemically and radiometrically determined uranium. The measured 234U/238U activity ratios for most samples were approximately unity, indicating that secular radioactive equilibrium was established between 238U and 234U in the El Sela mineralised rocks. On the other hand, 238U and 234U might be equally leached due to the effect of rock-water interactions during the pluvial time by the action of surficial or underground water. The 238U/235U activity ratios of the studied mineralised granites were significantly shifted from the natural ratio 21.7, indicating that the redox conditions and alteration processes played an important role in the fractionation of 238U from 235U. The values of 234U/235U ratios in the studied granites varied between 23.08 and 34.70 in different samples, suggesting 235U migration out due to the prevailing conditions.