Extraction and Separation of Se, Zr, Pd, and Cs Including Long-Lived Radionuclides

Abstract

The solvent extraction of Se(IV), Zr(IV), Pd(II), and Cs(I) from nitric acid into 1-octanol (OC), or 1-octanol and n-dodecane has been performed. These elements include long-lived radionuclides in spent nuclear fuels, so a simple separation method is indispensable for the development of the treatment of high-level liquid radioactive waste. It was found that Se can be extracted using phenylenediamine, Zr(IV) can be extracted using tetraoctyl diglycolamide and di-2-ethylhexyl phosphoric acid, and Pd can be extracted using (methylimino)bis(N,N-dioctylacetamide) and N,N,N',N',N",N"-hexaoctylnitrilotriacetamide. These elements can be recovered in over 90% yield by these extractants from nitric acid into OC. A distribution ratio of Cs(I) of greater than 1 can be obtained using di-t-butyldibenzo-18-crown-6. It is clear that 90% recovery of Cs(I) can be achieved using an extraction solvent with ten times the volume of the aqueous phase.

Extractions and Spectroscopic Studies of Various Metals with Diglycolamide-Type Tridentate Ligands

“…Generally speaking, alkali and alkali earth metals can be extracted by crown-ether compounds having 5 or greater numbers of oxygen atoms. Ln in group 3 can be extracted easily by TODGA, and Zr is extractable by TODGA and HDEHP[5][6][32][33][34]. Earlier publications also supported the present results, concerning the easy extraction of In and Bi by HDEHP and that of Pb with the crown ether compound[35][36][37].From group 5 to 10 and 16 inTable 1, MIDOA shows the highest extractability of all.…”

A Review of Environmental and Economic Implications of Closing the Nuclear Fuel Cycle—Part One: Wastes and Environmental Impacts

“…Indian teams have recovered caesium from HLW, followed by vitrification into pencils for use as blood irradiators in medical applications [83]. The IMPACT programme in Japan has considered the separation of various radionuclides from wastes with potential value, including 107 Pd and 93 Zr [84].…”

Solvent Extraction of Cesium Using DtBuDB18C6 into Various Organic Solvents

“…Cs is one of the elements that is required to be removed from high-level radioactive waste (HLW) [1][2][3][4][5] because of its relatively high yield in fission products, 30-year half-life of 137 Cs, emission of strong gamma (661.7 keV) and beta rays (512 keV), and strong heat generation in all fission products and actinides. The heat generated by Cs is problematic when producing vitrified waste or MA fuels.…”

“…Hence, recovery of Cs from HLW and its introduction into interim storage is an important task for the atomic energy field. In addition, the development of a chemical recovery method for Cs and transmutation to 135 Cs, which shows very long halflife (T 1/2 = 2.3 × 10 6 y), is currently one of the most important tasks [3]. Solid-liquid separation methods, such as adsorption on zeolites and ferrocyanides, have been widely applied to recover Cs up to the present day [6][7][8][9][10]; however, because of the strong bond of Cs to the solid absorbents, this technique requires large volumes of effluent.…”