Nuclides extraction extractants

Nuclear-physical methods ai e the basic ones in controlling environmental pollution which results from nucleai -power complexes and power plants work. Oil and gas production leads to the extraction of radio nuclides of natural origin in considerable amounts, which later spread from oil-slimes and water wastes in the neighborhoods of oil and gas producing entei prises. Similaidy, toxic and radioactive elements can pollute environment in case of mineral deposits extraction. 

An important feature of both flowsheets is that the oxidation state of plutonium does not have to be adjusted because all three states, III, IV, and VI, extract. Another feature of the flowsheets is that Am(III) and Cm(III) follow Pu through the separation scheme and thus behave as denaturing nuclides. 

The two Mossbauer levels of Pt, 99 keV and 130 keV, are populated by either EC of Au(fi/2 = 183 days) or isomeric transition of Pt(fi/2 = 4.1 days). Only a few authors, e.g., [323, 324] reported on the use of Pt, which is produced by thermal neutron activation of " Pt via " Pt(n, y) Pt. The source used in the early measurements by Harris et al. [322, 325] was carrier-free Au diffused into platinum metal. Walcher [326] irradiated natural platinum metal with deuterons to obtain the parent nuclide Au by (d, xn) reactions. After the decay of short-lived isotopes, especially Au(fi/2 = 6.18 days), Au was extracted with ethyl acetate, and the Au/Pt source prepared by induction melting. Buym and Grodzins [323] made use of (a, xn) reactions when bombarding natural iridium with... 

Other techniques are used for shorter time scales, including the measurement of the 226Ra Ba ratio in barite extracted from sediments (Paytan et al., 1996). This technique has a time scale of about five thousand years. Alternately, assessments of rapid sedimentation and bioturbation on time scales of days to centuries require shorter half-life nuclides such as 210Pb, 228Th, 234Th, and 222Rn. 

Often the products of nuclear reactions have very short half-lives. This is especially true for the heaviest elements obtained by bombardment of heavy targets with heavy ions. To identify and characterize such short-lived nuclides, fast separations are required solvent extraction techniques are well suited to provide the required fast separations. For example, the SISAK method [68] has been successfully used in conjunction with in-line gas jet separators at heavy ion accelerators to identify short half-life actinide isotopes produced by collision of heavy atoms. The Sisak method involves use of centrifugal contactors, with phase residence times as low as tenths of a second, in conjunction with in-line radiometric detection equipment. 

Dozol, J. F. Scwing-Weill, M. J. Arnaud-Neu, F. Bohmer, V. Ungaro, R. van Veggel, F. C. J. M. Wipff, G. Costero, A. Desreux, J. F. de Mendoza, J. Extraction and Selective Separation of Long-Lived Nuclides by Functionalized Macrocycles, European Commission, Nuclear Science and Technology series, EUR19605 EN 2000 p. 198. 

The stability of iron oxide suspensions is relevant to fields as varied as the paint industry, extraction of iron from its ores, the structure of soils, hydrometallurgy and waste water treatment. The ease of homogensisation of paint, for example, is controlled by proper adjustment of the stability of the pigment suspensions. In ground waters, the settling behaviour of small iron oxide particles influences transportation of trace elements and radio-nuclides. The stability of a dispersion of magnetic particles can determine the quality of ferrofluids and magnetic tapes. 

The accurate activity of the nuclide in the extracted melt will be the average values of these functions for the residual melt with respect to X, the mass fraction of extracted melt relative to the initial amount (Williams and Gill, 1989)... 

The distribution coefficients of the parent and daughter nuclides are important in U-series disequilibria. If the parent has a higher distribution coefficient than the daughter, its extraction from the matrix is retarded and the daughter/parent activity ratio in the melt can be greater than 1. Experiments have shown that Dy > Dj for garnet peridotites but Du spinel peridotites at low pressures. Due to experimental difficulties, Dro and Dpa are not directly known but are inferred to be very small. Therefore, it is reasonable to assume Dj, >Di and Du > Dp for both garnet peridotites and spinel peridotites. 

Ion exchange and solvent extraction techniques have been used extensively as the basis for radiochemical generators exploiting the differences in absorption behavior between the parent nuclide and its useful daughter nuclide. Many parent/daughter pairs of nuclides have sufficiently different polarographic half wave potentials so that their electrochemical behavior may be exploited for rapid separation of the daughter from the parent with minimal contamination of the product with the parent isotope. ... 

Dozol, J.E., Schwing-Weill, M.J., Amaud-Neu, F. et al. 2000. Extraction and selective separation of long-lived nuclides by functionalized macrocycles European Commission, Nuclear Science and Technology Report. EUR 19605. 

Extraction of Nuclides by Mixture of Acids and Neutral Compounds.361... 

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