الفهرس 
I.1. General StatementsOnly 14 pages are availabe for public view
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Abstract
Around Abu Zeneima area situated at Southwestern Sinai, the Lower Carboniferous sedimentary sequences have been found mineralized by various economic metallic values. A uranium-vanadium occurrence that is mainly manifested in the form of the vanadium mineral carnotite [K2(UO2)2(VO4)2.3H2O] and which is rimmed by the phosphate mineral metatorbernite [Cu (UO2)2(PO4).8H2O] has lately been identified in the kaolin rock at Wadi El- Sahu area. This occurrence is actually in association with the manganese- iron ore of Southwestern Sinai. The Mn-Fe occurs essentially in the form of lenticular bodies within the lower member of Um Bogma Formation belonging to the Lower Carboniferous age. The Mn-Fe ore is mainly represented by pyrousite together with goethite and kaolinite. Previous mineralogical studies have concluded that the U occurrence in the studied area belongs to two generations; namely an older one associated with the Mn lens, shale and dolostone rocks without discrete U minerals and while most of this U was decayed to radium and/or migrated out, the younger generation occurs as encrustations on the kaolinite surface. Mineralogically, the latter is represented by an earlier carnotite and later metatorbernite minerals. The present work is mainly concerned with the hydrometallurgical processing of wadi El Sahu carnotite-bearing kaolin ore material for the separate extraction of the U and V metal values. The collected sample was found to assay 26,000 ppm U (2.6 %) while the accompanying V assay 12,000 ppm (1.2%). The chemical analysis of the working ore indicated that the clay mineral kaolinite [ Al4Si4O10(OH)8] amounts to 41.5% while silica and iron oxides attain 32.10 and 9.4%, respectively. In addition, the mineralogical analysis of the ore minerals has also been performed by using The present work is mainly concerned with the hydrometallurgical processing of wadi El Sahu carnotite-bearing kaolin ore material for the separate extraction of the U and V metal values. The collected sample was found to assay 26,000 ppm U (2.6 %) while the accompanying V assay 12,000 ppm (1.2%). The chemical analysis of the working ore indicated that the clay mineral kaolinite [ Al4Si4O10(OH)8] amounts to 41.5% while silica and iron oxides attain 32.10 and 9.4%, respectively. In addition, the mineralogical analysis of the ore minerals has also been performed by using Two leaching techniques should be studied namely; the agitation leaching using dilute H2SO4 and the pug acid leaching technique using conc. H2SO4 without water for the simultaneous leaching of both metal values. In both techniques, several relevant factors were studied including the effect of H2SO4 concentration, leaching time and temperature as well as the effects of oxidation and the solid/liquid ratio. The agitation leaching technique gave leaching efficiencies 83.8% U and only 52.1 % V, when using an acid concentration of 200 g/l, S/L ratio of 1/5 for 2 hr leaching time and a leaching temperature of 500C besides mixing of the ore material ground to -200 mesh size with KMnO4 as an oxidant (0.5%). The agitation acid leaching data was ascertained that both acid concentration and temperature are quite important for increasing the leaching efficiency of the studied metal values. Accordingly, it was found more promising from the economic point of view to study the pug leaching technique for obtaining reasonable leaching efficiencies of both U and V. The pug leaching techniques performed at two ore samples ground -100 and -200 mesh size under curing temperature 300oC for 4 hr and an ore / conc. Acid ratio 1/1. The obtained data indicating the ore material ground -100 mesh size exhibit 48% and 16.7% leaching efficiency for U and V, respectively. However, the maximum leaching efficiencies of U and V have attained 80.7% and 86.7%, respectively, with increasing the working ore fineness to -200 mesh size. These results reflect actually the different modes of U and V occurrence in the study ore material where besides their presence in the form of carnotite and possible titanomagnetite minerals, both are partially present in the form of adsorption upon the clay and the iron oxides minerals. The separate recovery of both U and V from their leach liquor were done by solvent extraction process (namely the cationic extractant DEHPA and an anionic amine extractant). It was found convenient in the present work to successively apply both solvents. Thus, in the first SX circuit using DEHPA and after proper oxidation of V by H2O2 to exist in its anionic pentavalent state (VO3- and VO43- ), only U would selectively be extracted as the uranyl cation (UO22+). The anionic pentavalent V left behind in the leach liquor was then extracted by the anionic extractant Aliquat-336. A synthetic U/V solution assaying 1000 ppm U and 1400 ppm V was properly prepared to optimize the corresponding relevant extraction conditions after its oxidation with 50% H2O2. The U and V assay were decreased to 667 ppm U and 933 ppm V. This indicated that the optimum factors for complete U extraction without any accompanying V have involved a pH of 2.5 for contact time 5 min and using an O/A ratio of 1/1.5 and 0.01 to 0.05 M DEHPA. However, increasing the DEHPA concentration to 0.1 M has resulted in co-extraction of V to the extent of 14% and which was avoid by increasing the pH to 2.5. The separate and recovery of U/V from the working El Sahu leach liquor were explained by using the same optimum conditions of synthetic solution. Analysis of the prepared leach liquor from pug optimum conditions, revealed an assay of 2054 ppm U and 1020 ppm V. Taking the above mentioned optimum conditions for separate U extraction in consideration, the factors affecting DEHPA selective U extraction from the prepared El Sahu leach liquor have been studied after its oxidation with 50% of its volume by H2O2. Accordingly, the uranium-vanadium assay has been decreased down to 1370 and 680 ppm respectively. The optimum relevant extraction conditions at which U has been completely extracted are 0.05 M DEHPA at an O/A ratio of 1/1 at pH 2.5 for contact time 5 min. This was then followed by V extraction which has become in its anionic pentavalent state, using Aliquate-336. The corresponding relevant factors for complete V extraction have been studied and which were found to include an Aliquat-336 concentration of 0.05 M for 5 min at pH 2.5 and using an O/A ratio of 1/1. On the other hand, the O/A ratio has also been studied for U and V by DEHPA and Aliquat-336 solvents, respectively. from the obtained data, the corresponding McCabe-Thiele extraction diagrams for both solvents were then constructed and have indicated that two theoretical stages in a counter-current system would be required for either. Finally, all the above data have indeed been properly collected into an integrated flowsheet for the separated recovery of U and V. The flowsheet would involve the pug leaching technique followed by the successive application of DEHPA for U recovery and then Aliquqt-336 for V recovery.