الفهرس 
INTRODUCTION AND LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The aim of this study has been to clarify the behavior and distribution of radionuclides in different rock types, different locations, different degrees of alterations and its effects by the chemical and physical properties prevailing during formation and processing of these rocks in Sinai and Eastern Desert.
In the first part, to study the radionuclides transfer from the solid material (ore) to the liquid phase (acid and/or alkali solutions), sixteen samples of different rock types from Sinai and Eastern Desert were collected and prepared for different analyses. These samples have been characterized by different analyses such as gamma-ray spectrometry by high purity germanium (HPGe), X-Ray Diffraction (XRD), and wet chemical analysis. The collected samples are chemically categorized under the following types; high silica, mainly silicates, high carbonates and high organic matter. It is necessary to consider briefly the features which affect chemical composition, such as degree of source weathering. So, the chemical index of alteration was calculated for different rock types in Allouga and Eastern Desert. Sedimentary rock samples of Allouga and granites from Gattar have slightly to moderately weathered source terrain while El Sela samples have strongly weathered source terrain. 232Th/238U concentration ratios of Allouga and Eastern Desert (< 2) are highly suggestive of relative uranium enrichment, and implicate reducing conditions.
The variables in this study include different rock types, different acids and alkalis, different radionuclides. These variables played their role in the transfer of different radionuclides from solid (original sample) to solution (leachates) and from solution to solid (residual).
In the second part, Allouga samples were studied and the results showed the following remarks:
1. The transfer of some radionuclides was carried out by two processes; either physically through α–recoil or chemically through dissolution, complexation, chelation and ion-adsorption.
2. The more pronounced radionuclides in one sample showed the physical transfer of 234U and 230Th in which the apparent leachability reached 117.63 % for 234U and 63.46 % for 230Th, although Th is immobile in the normal conditions.
3. The high carbonate samples showed very low leachability for 238U and 235U (12.13 %) and 234U attained 28.83 % which is very low also if compared by other types of samples. This may be due to the high consuming of acid by the high carbonate content.
In the third part crystalline rocks from the Eastern desert were studied and the results showed the following:
1- The leachability for 238U and 235U ranged from 18.69 and 18.70 % in microgranite dike sample (ES2) to 88.36 and 88.57 % in Hammamat sediments sample (GV), respectively.
2- The leachability for 234U varied from 68.25 % microgranite dike sample (ES2) to 104.67 % microgranite dike sample (ES1).
3- The maximum amount of 234U % transfer to solution by chemical leaching was 88.36 % in sample (GV) and that by physical transfer (α-recoil) was 55.00 % in microgranite dike sample (ES1) while the minimum amount of them are 18.69 % in microgranite dike sample (ES2) and 18.93 % in dolerite dike sample (ES3), respectively.
For ore samples in the studied localities, all cases of U leaching are characterized by (234U/238U) AR < 1 and all cases of U accumulation are distinguished by the relation (234U/238U) AR > 1. Plotting of the samples deviating from secular equilibrium, i.e., larger than 1.10 or less than 0.90 for 234U/238U, 230Th/238U, 230Th/234U and 226Ra/230Th, fall into the forbidden region.
The 234U/235U values are useful in evaluating recent aqueous alteration events resulting in either gain or loss of 234U in the uranium mineralization while the other ratios as 238U/235U, 230Th/238U, 230Th/234U, 226Ra/238U and226Ra/230Th show fractionation that occurred during formation and subsequent alteration of mineralization.
The effect of acid type is very pronounced in the leachability, the results show that the leachability could be arranged in the order HNO3 > HCl > H2SO4 for both of 238U, 235U and 230Th radionuclides. The maximum transfer of 234U reached to 114.47 % using HCl. 226Ra is more leachable by HCl (47.21 %) and HNO3 (36.18 %) rather than H2SO4 (4.53 %), due to the formation soluble RaCl2 and Ra (NO3)2. On the other hand by using alkaline leaching on dolomite sample, the behaviour of uranium isotopes 238U and 235U is nearly identical for acidic and alkaline leaching.