| Abstract: |
SummaryThis thesis is mainly concerned with studies related to the extraction and determination of uranium from 6M HNO3 acid solution using 0.02M triphenylphosphine oxide (TPPO) dissolved in toluene for its separation.Certain solvents namely such as toluene, benzene, xylene were used as diluents for preparing certain concentrations of the extractant TPPO. It was found that toluene is the most suitable diluent for preparing the extractant solution. The recovery of uraniThe effect of the organic phase; TPPO to aqueous phase ratio (O/A) was studied using certain volume of the organic extractant which was extracted by certain volumes of organic extractant to reach the maximum extraction with minimum volume of the extractanThe effect of extractant concentration was studied using certain concentrations of organic extractant (0.2, 0.1, 0.05, 0.04 0.02M). It was found that, the best extractant concentration is 0.02M TPPO in toluene at 4:1 V/V aqueous to organic phase ratio whiIn general, the extraction percentage, %E increases with decreasing the concentration of TPPO from 0.2 to 0.02M to reach 98.7% uranium extraction at 4:1 V/V aqueous to organic phase ratio for one cycle.The effect of temperature was studied at certain temperatures from 22 to 100oC under constant condition of other factors. It was found that the ambient room temperature 22o±1C can be considered as the best temperature degree which gives 98.7% of uranium eThe effect of pH was studied by varying the pH values from 0.5 to 1.0. It was found that with the decrease of pH values, the uranium extraction increases. The best uranium extraction percentage (98.7%) was reached at pH 0.5.The effect of shaking time was studied on fixing the other affecting parameters. The time periods which were applied during the experiments are 1, 2, 3, 4, 5 and 6min. The uranium extraction was calculated at each time period of shaking. It was found thatThe extraction of uranium using TPPO in toluene was done covering a long period from 0 min to 4.32 x 103 min to evaluate the stability. It was found that , the extraction increased up to 10 min, then it became constant untill 432 x103 min, so that the besCertain stripping agents were tried for back extraction of uranium from the organic phase. 5ml portion of 0.2- 1M sulfuric acid, hydrochloric acid and nitric acid were used. The maximum stripping values of uranium were 67.5%, 77.5 and 97.5%, respectively.The effect of presence of interfering ions on the extraction and determination of U (VI) from uranium nitrate mixed with 6M HNO3 acid was studied. In this respect, the extraction of uranium was performed at first without the presence of any interfering ioIn the present work, the geological samples were collected from different areas of Egypt. Five representative samples were collected from Sinai and seven samples from Um Tawat Intra-Cratonic Basin, Eastern Desert. The representative samples were prepared The standard, international and reference samples were treated for leaching the uranium content with 20 ml of 6M HNO3 acid from 0.2 g of each sample. This sample is washed; uranium is extracted by TPPO and determined by using Arsenazo-III. It was found exStandard rock and geological samples were prepared for chemical analysis using two ways. First using a mixture of acids and second by 6M nitric acid to determine the major and trace elements in each case. It was found that the major and trace elements werThe percentage of error (Error %) and accuracy () in standard reference and geological samples showed values of less than + 3 declaring high accuracy and precision for the obtained results.Thus the present work offers a new method for dissolving, extracting and determining of uranium in geological samples with high accuracy and precision. Moreover considerable differences in economy and time duration of the proposed method were also verifie
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