Mobilisation of radionuclides during uranium and gold processing of granitic rock at El-Missikate area, central Eastern Desert, Egypt.

The present work is concerned with the fractionations of 238U, 230Th, 226Ra,214Pb, 214Bi, 235U, 228Ac, 208Tl and 40K in sulphuric acid leaching and solvent extraction of uranium, in addition to, thiourea leaching of gold. The activity concentrations of the studied radionuclides indicate that uranium isotopes are highly leachable (89–90%) in sulphuric acid, while 230Th and 208Tl are leached with efficiency of about 76% and 71%, respectively. Less than 35% of 226Ra,214Pb, 214Bi and 228Ac are leached. In solvent extraction processes, uranium isotopes are selectively extracted and stripped. While 208Tl extraction was only 13%. Most of 230Th, 226Ra, 214Pb and 40K could not be extracted at such pH. The leachability of the studied radionuclides was significantly low using acidic thiourea. The dose rate and radium equivalent, in addition to the external and internal hazard indices values for the original sample and the uranium and gold tailings are higher than the recommended maximum values. [ABSTRACT FROM AUTHOR]