高純度テルル中の鉛およびビスマスの定量

概要

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A method for the determination of lead and bismuth in high purity tellurium was presented. Sample was dissolved in HCl and HNO3 and evaporated to almost dryness. The residue was taken up in HCl and evaporated to dryness again. This procedure was repeated once to complete the reduction of Te6+ to Te4+, and the final was dissolved in HC1. The solution was made alkaline by addition of NH4OH and KCN, and lead and bismuth were extracted by dithizone-chloroform to be separated from tellurium. The condition for extracting lead and bismuth had been investigated by using RaD and RaF as tracers and it was confirmed that the optimum pH for extraction was about 10. Lead and bismuth were stripped together by-dil. H2SO4 and bitmuth was determined photometrically by dithizone extraction from the slightly acidic solution containing phthalic acid. Lead was determined also photometrically by dithizone extraction from the remaining aqueous layer which had been treated by dithizonechloroform to remove bismuth and made alkaline with NH4OH. Micro amount of lead and bismuth as low as 0.5ppm in tellurium could be estimated at a time by the proposed method.
社団法人日本分析化学会の論文