ABSTRACT
A neutron-activation method has been developed for the determination of the active constituents and contaminants in hydrogenation catalysts. The active constituents of palladium and nickel catalysts (Pd and Ni) and Zn and Co contaminants present in small amount were determined by a direct instrumental method. A NaI(Tl) scintillator and a Ge(Li) semiconductor connected to a multichannel analyser were used for the measurements. A computer was used to evaluate the gamma-spectra. Contaminants present in small amount were also determined by means of a radiochemical separation method based on heterogeneous isotopic exchange on mercury(II) sulphide and zinc sulphide precipitates.
ABSTRACT
The retention of various radionuclides on metal sulphide precipitates has been studied. The sulphide precipitates quantitatively retained the common radionuclides. The condition for 100% retention in a thin layer is small particle size (a few microm) in the precipitate. This can be ensured by pulverization of the dried precipitate of metal sulphide. (203)Hg(2+) is retained by mercury sulphide and (65)Zn(2+) by zinc sulphide by isotopic exchange. The retention of foreign radioactive ions can be reduced or even eliminated by counter-carrier technique in cases where the retention is not due to chemical reaction, precipitate exchange. The isotopic exchange with mercury(II) sulphide and zinc sulphide enables mercury and zinc ions to be separated rapidly and determined in the presence of a number of interfering ions.
ABSTRACT
A method for the determination of tin in nickel by activation analysis is described. Isotopic exchange is used for the separation of tin from nickel. The most favourable conditions for the separation have been determined, under which more than 99 % of the tin can be recovered in 7-8 min.
