Gadolinium , separation

Gadolinite, extraction of, 2 44 Gadolinium, separation of europium from samarium and, as magnesium nitrate double salt, 2 57 separation of samarium from, in acetate solution with sodium amalgam, 5 36... 

Europe) In 1890 Boisbaudran obtained basic fractions from samarium-gadolinium concentrates which had spark spectral lines not accounted for by samarium or gadolinium. These lines subsequently have been shown to belong to europium. The discovery of europium is generally credited to Demarcay, who separated the rare earth in reasonably pure form in 1901. The pure metal was not isolated until recent years. 

From gadolinite, a mineral named for Gadolin, a Finnish chemist. The rare earth metal is obtained from the mineral gadolinite. Gadolinia, the oxide of gadolinium, was separated by Marignac in 1880 and Lecoq de Boisbaudran independently isolated it from Mosander s yttria in 1886. 

Fuel Dissolution. In the American and British plants, LWR fuel pieces typically fall directly from the shear into a dissolver basket, which fits inside the dissolver vessel. A soluble poison such as gadolinium is added to the nitric acid to prevent criticahty. The massive end fittings are sometimes separated from the fuel pieces before the latter enter the dissolver. The French have installed continuous rotary dissolvers in the UP3 and UP2-800 plants at La Hague. The units each consist of a dmm rotating within a geometrically favorable slab tank (13). 

Silvery, artificial element generated by beta decay from a plutonium isotope (239Pu). Chemically similar to gadolinium. Like Eu and Gd, Am and Cm are difficult to separate. It can be produced in kilogram amounts. The most common isotope is 244Cm with a half-life of 18.1 years. Is used for thermoelectric nuclide batteries in satellites and pacemakers. It is strongly radioactive and hence also suitable for material analysis. 

It is known that below the ordering temperature, the — ASM of a paramagnet will quickly reduce to zero, thus defining the temperature range in which the material can be usefully employed. Note that gadolinium metal works best at room temperature, which constitutes a separate and productive area of research with... 

Raebiger JW, Bolskar RD (2008) Improved production and separation processes for gadolinium metallofullerenes. J. Phys. Chem. C 112 6605-6612. 

Other chemists also worked to separate gadolinium from the mineral dydimia. Paul-Emile Locoq de Boisbaudran, following clues provided by Marignac, isolated element 62 (samarium)... 

Holmium is obtained from monazite, bastnasite and other rare-earth minerals as a by-product during recovery of dysprosium, thulium and other rare-earth metals. The recovery steps in production of all lanthanide elements are very similar. These involve breaking up ores by treatment with hot concentrated sulfuric acid or by caustic fusion separation of rare-earths by ion-exchange processes conversion to halide salts and reduction of the hahde(s) to metal (See Dysprosium, Gadolinium and Erbium). 

By increasing the temperature of an ion exchange system, more rapid separation can be performed. In fact, temperature modifies the separation factor of two neighbor elements. For example, by increasing the temperature from 25°C to 95°C, the 1.5 samarium-europium separation factor becomes 1.8 and the europium-gadolinium 1.1 separation factor goes to 1.5. Thus the difficult Eu-Gd separation at 25°C becomes "easy" at 95°C. 

The importance of this system for the separation of the trivalent species from each other was recognized in 1953 by D. F. Peppard and his collaborators at the Argonne National Laboratory. This was followed in the same year by the isolation of the "first kilogram" of pure gadolinium by B. Weaver and his co-workers at the Oak Ridge National Laboratory using the same method. Subsequently, the method has been used on both a laboratory and a commercial scale. 

Table II summarizes the losses we experienced at each step of the target preparation procedure. As the table shows, the most inefficient aspect of our technique is the isotope separation step. Normally, we expect 30% recovery with isotope separation of gadolinium, but this level was obviously not obtained in this particular case. With other rare-earth materials, such as europium and samarium, the expected isotope separation recovery is > 50% and can reach levels as high as 70%. Therefore, allowing for similar chemistry losses, we expect that in those selected cases where isotope separation recoveries are 50%, the amount of initial material required to make a reasonable number of usuable targets can be as low as 100 yg. The amount of intial material required can also be reduced somewhat by paying more attention to increasing the efficiencies of the wet-chemistry yields.

The chemical yields were determined by gamma-counting techniques. The sample contained a number of radioactive isotopes of gadolinium prior to isotope separation. 

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