The Significance of Mobilization and Immobilization of Specific Radionuclides for Optimum Bioleaching Conditions Using Aspergillus lentulus

AbstractGamma spectrometry is applied for measurement of natural radioactivity by Hyper-pure germanium (HPGe) systems during the application of bioleaching optimum conditions in ore and waste samples. The bioleaching of the ore sample using isolated fungusA. lentulus indicate that the bioleaching efficiency of234U,232Th are higher than238U,230Th and235U which may attributed to the effect α-recoil rate for234U, organic matter, clays or iron oxide and or/lower activity concentration of232Th. The immobilization of238U,235U,230Th,214Pb, and214Bi in ore and waste samples could be result from high organic matter content, iron, and manganese oxides, in addition to the role of microbes that can resist leaching by their cellular compounds. The high mobility of some radionuclides in waste samples may be resulted from the leaching process of the original rocks using acid solution that clean the grain surfaces leaving spaces around the grains and this permit the organic acids to reach the inner parts of the grains during bioleaching processes leading to the high mobility234U,232Th and to lesser extent238U and235U. The radionuclides226Ra,214Pb and214Bi were found almost totally in the residue of two sample (Q and W) indicating to be associated with radium sulphate or relatively insoluble mineral phases like alumina silicates and refractory oxides.
Source: Physics of Particles and Nuclei Letters - Category: Physics Source Type: research