The aqueous geochemistry of the rare-earth elements and yttrium

The effect of nitric acid concentration on the selectivity of a novel extraction chromatographic resin consisting of an octanol solution of 4,4′(5′)-bis(t-butyl-cyclohexano)-18-crown-6 sorbed on an inert polymeric support for strontium over a number of alkali, alkaline earth, and other metal cations was evaluated. The effect of macro quantities of selected elements on strontium retention by the resin was also examined. The resin is shown to exhibit excellent selectivity for strontium over nearly all of the test elements; only lead and tetravalent neptunium, polonium, and plutonium show significant affinity for the material. In addition, concentrations of calcium or sodium ion up to ∼ 0.1 M. are shown not to diminish the sorption of strontium appreciably. Several useful radiochemical separation schemes devised on the basis of the results obtained are described.

A novel strontium-selective extraction chromatographic resin*

Separation and preconcentration of actinides by extraction chromatography using a supported liquid anion exchanger: Application to the characterization of high-level nuclear waste solutions

Synthetic inorganic ion-exchangers-I Hydrous oxides and acidic salts of multivalent metals.

Two new extraction chromatographic resins containing the diglycolamide class of molecules have been prepared and characterized, and potential applications identified. The new resins consist of 40 weight percent N,N,N′N′ tetraoctyldiglycolamide (TODGA) and N,N,N′N′ tetrakis‐2‐ethylhexyldiglycolamide (TEHDGA) sorbed onto 50–100 µm particle size Amberchrom® CG‐71. The new resins have capacities for Eu of approximately 0.086 mmol/mL of bed and are quite stable to extractant leaching. The resins were characterized by measuring the batch uptake of actinides, lanthanides, and yttrium, alkaline earths and 13 selected transition and post‐transition elements from HNO3 and HCl. Based on the uptake data, a number of very efficient separations were achieved using 0.5–2 mL bed volume columns and room temperature operation.

Novel Extraction of Chromatographic Resins Based on Tetraalkyldiglycolamides: Characterization and Potential Applications

Analogous actinide (III) and lanthanide (III) tetrad effects

Interfacial activity of liquid-liquid extraction reagents—I

Chemical separations for super-heavy element searches in irradiated uranium targets

The mechanism of interfacial mass transfer of calcium in the system: Di(2-ethylhexyl)phosphoric acid in dodecane-dilute nitric acid

The distribution of mass in the spontaneous fission of $^{256}\mathrm{Fm}$ has been investigated by the radiochemical determination of the fission yields for 28 mass chains. The mass distribution is asymmetric with a peak-to-valley ratio of \ensuremath{\sim}12. The average masses of the light and heavy groups are 111.9 and 141.0, respectively. The fission-yield data indicate a value of 3 \ifmmode\pm\else\textpm\fi{} 1 for $\overline{\ensuremath{\nu}}$, the average number of neutrons emitted per fission. A comparison of the characteristics of the mass distribution for low-energy fission of nuclides ranging from $^{227}\mathrm{Th}$ to $^{256}\mathrm{Fm}$ is given.

E.P. Horwitz

Papers

Analogous actinide (III) and lanthanide (III) tetrad effects

Interfacial activity of liquid-liquid extraction reagents—I

Chemical separations for super-heavy element searches in irradiated uranium targets

The mechanism of interfacial mass transfer of calcium in the system: Di(2-ethylhexyl)phosphoric acid in dodecane-dilute nitric acid

Distribution of Mass in the Spontaneous Fission of Fm 256