Fundamental Studies on the Extraction of Uranium from Phosphoric Acid with various Organophosphorus Compounds

P(論文)The particular emphasis has been placed upon the items as followed; 1) The selection of diluents to obtain higher distribution ratios, 2) The effect of their concentration of reagents, 3) The effect of extracting temperature, 4) The condition of reducing uranium (VI) to (IV). As a reducing agent, iron powder is most effective. The extraction ratio of uranium (IV) was remarkably decreased with the addition of TOPO in organic phases and on the other hand the addition of it outstandingly enhanced the extraction ratio of uranium (VI). It seems that reagents such as TOPO or D2EHPA play a role of a diluent or a solvent and the employment of such polar solvents is unsuitable for the extraction of uraninm. Further, the both extraction reaction would proceed exothermically. The composition of the complex of uranium (VI) extracted was UO_2 (D2EHPA)_2TOPO. The distribution ratio of uranium (IV), 140 was obtained when the mixture of 3g of OPPA, 0.5g of biphenyl, and 0.5g of naphthalene was used as the organic phase, and the distribution ratio of uranium (VI), 12 was obtained when the mixture of 1g of TOPO, 3.4g of D2EHPA and 1.6g of paraffin (mp 48℃) was used.departmental bulletin pape