MAISA M. AMIN*, I.E. ELAASSY*, M.G. EL-FEKY*, A.M. SALLAM**#, MONA S. TALAAT**, NILLY A. KAWADY*
*Nuclear Material Authority, Cairo, Egypt
** Physics Department, Biophysics Group, Faculty of Science, Ain Shams University, Cairo, Egypt
The strategic situation of Sinai made it an urgent national target for the sustainable development. One of the important factors in such development is the exploration and the processing of uraniferous rock materials. Consequently, the Lower Carboniferous sedimentary rocks were chosen for the present study to test the uranium bioleaching capacity of fungal strains isolated from exposed sedimentary rocks in southwestern Sinai. Eight fungal species were isolated from three grades of uraniferous sedimentary rock samples in southwestern Sinai, Egypt and tested for their bioleaching activity. Aspergillus niger (A. niger) and Aspergillus terreus (A. terreus) were the only isolates which gave a high grade leaching efficiency of uranium from the studied uraniferous rocks. The most favorable factors for solubilization of uranium were 7 days incubation time, 3% ore concentration, solid/liquid ratio 1/3 and 30 °C incubation temperature. Both fungi produced organic acids (oxalic, citric, formic and ascorbic) in the culture filtrate which are the key compounds of bioleaching processes. Applying these conditions on one kilogram of Ag-3 sample (the lowest U grade), the A. niger strain gave high uranium leaching efficiency of 71.4%. The recovery test of U, have been performed by proper precipitation to obtain a high quality uranium concentrate.
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