[en] The application of the reagent for the spectrophotometric determination of traces of zirconium is described. The effects due to acid concentration, reagent concentration, time and diverse ions are reported. Beer's law is obeyed and the molar absorbance coefficient at 577 nm is 3.2 X 10⁴. (author)

[en] Published in summary form only

[en] The original Macdonald and Savage amperometric method scaled down to milligram-sized plutonium samples was further modified. The electro-chemical process of each redox step and the end-point of the final titration were monitored potentiometrically. The method is designed to determine 4 mg of plutonium dissolved in nitric acid solution. It is suitable for the direct determination of plutonium in non-irradiated fuel with a uranium-to-plutonium ratio of up to 30. The precision and accuracy are ca. 0.05-0.1% (relative standard deviation). Although the procedure is very selective, the following species interfere: vanadyl(IV) and vanadate (almost quantitatively), neptunium (one electron exchange per mole), nitrites, fluorosilicates (milligram amounts yield a slight bias) and iodates. (author). 15 refs.; 8 figs.; 7 tabs

No abstract available

[en] The scattering of conduction electrons by the localized moments of heavy rare earth ions in Lu is investigated by analysing previously published resistivity measurements. The crystal field splitting of the 4f-levels is taken into account and satisfactory agreement obtained with experiment. (Auth.)

[en] Published in summary form only

[en] Some theoretical and practical aspects concerning the direct fluorimetric determination of uranium in minerals are presented together with a comparison of a series of practical results of this methodology with those obtained by other techniques. The investigation of the reduction of uranium fluorescence by interfering elements (''quenching'') was continued and further evidence provided that the dependence of this phenomenon on the quencher concentration may be - within certain limits - described by the Lambert absorption law. The characteristic parameter of this dependence, the ''half-concentration'', has been determined for eight further elements, namely Ni, Co, Zn, Cd, Zr, Th, Ce and Cu. Further more the influence of the quencher/uranium ratio on the results of analysis using the ''internal standard'' (spike) method has been investigated [with Fe(III) as model quencher] up to Fe(III)/U = 5000; there was no dependence observed within the limits of error. (auth.)

[en] Neodymium is a valuable rare earth metal with a wide variety of applications, apart from being an essential component of alloys that are used for making permanent magnets. It is extracted in the form of neodymium oxide, which has to be converted to neodymium fluoride to facilitate metallo-thermic reduction, to obtain pure metal with very low oxide content. Literature suggests three general methods of hydro-fluorination for the preparation of the rare earth fluorides from the oxides

[en] The reaction of morpholine-N-dithiocarboxylic acid morpholinium with niobium is suitable for the UV-spectrophotometric determination of small amounts of niobium. The effect of diverse ions was investigated and the method tested statistically. The determination of niobium is possible up to an 500fold excess of tantalum and can be carried out in dusts of niobium oxide. The absorbance is to be measured at 272 nm with corresponding molar absorptivity of 53680l.mole^-1.cm^-1. Conformity to Beer's law was observed for 0.2 to 1.5 ppm of niobium. (Auth.)

No abstract available