Radiochemical studies on the extraction of uranium and some fission products by mixed extractants

The main aim of the present work is to investigate the extraction of uranium (Vi) using some oxygen donor ligands and the extraction of europium (III) and americium (III) using combined extracting agents. The thesis includes three main chapters: Chapter I, the introduction, covers the main aspects related to the chemistry and radiochemistry of the three studied elements (U, Eu and Am) with a special emphasis on their nuclear characteristics, their atomic and ionic properties and their aqueous chemistry. Also it covers a literature survey related to the extraction of the three investigated elements. Chapter II, the experimental, contains a detailed outline concerning the chemicals and reagents used in this study and the preparation of the radionuclides employed. It contains a description for the instruments used specially, for the counting systems as well as the different experimental techniques and the procedures utilized during this work. Chapter III, the results and discussion, is divided into two main parts. The first, contains the data obtained for the extraction of U(Vi) from different concentrations of nitric acid medium using two neutral donor ligands; triphenylphosphine oxide, ph3 p O, and tri phenyl arsine oxide, ph3 AsO, in chloroform. ph3 Aso is more efficient than ph3 pO from U O22+ extraction especially from dilute nitric acid solutions; ≤2 M. This result was discussed in terms of the difference in the electronegativity of arsenic and phosphorous atoms and the partial double bond character of the → As - O in ph3 AsO