Separation of Ru Isotopes

An extensive survey of the separation procedures used for Ru was prepared by Wyatt and Rickard [144], and a brief summary was published by Lavrukhina et al. [99]. 

Most of the separation procedures are based on the distillation of RUO4. As the following summary shows, many different oxidizing reagents and media were used. The history of the sample, i.e., the formation of complexes, apparently does not disturb the distillation procedure. 

The RUO4 is in general collected in NaOH. The following concentrations of NaOH have been used 0.25 M [104], 4 M [105, 168], 6 M [59, 70, 106, 135, 191], and 12 M [167]. However, also cone. HCl [97, 172], H2S04(-f Cr03) [43], and ethanol [174, 191] were proposed. To the alkaline solutions, in which RUO4 is not stable [179], ethanol is added to precipitate hydrated Ru oxide. Tc is not affected by the ethanol and stays in solution. The Ru oxide can easily be dissolved in HCl [59, 135, 191] or HBr [127]. 

The distillation and precipitation step may be repeated if a higher decontamination factor is needed. In most procedures either the Ru oxide or Ru metal is used to prepare the counting sample. For reduction to metallic Ru the reaction with Mg powder is favored [191, 199]. However, plating on less noble metals, like Cu [62, 76], or by electrolysis [5, 43, 59, 104] and precipitation as sulfide [99, 200] were proposed. The reduction of RUO4 on the surface of plastics can also be used [26, 37]. 

The decontamination factor (DF) can be increased without loss in the yield (Y) by adding scavenger precipitations, i.e., at the beginning besides Ru and Os also Te, Sn, In, Cd, Ag, Pd, Ru, and Y carrier are added and then successively HCl + HF, dimethylglyoxime, and benzoinoxime are used to precipitate Ag, Y, Pd, etc. 

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