Studies on Analytical Methods for Trace Elements in Metals by Using Radioactive Isotope. III : Determination of Tantalum by Means of Isotope Dilution Method

The determination of tantalum by isotope dilution method in the presence of niobium was investigated by the use of radioactive isotope tantalum-185. Tantalum was separated from niobium as tantalum-tannin precipitate under the optimum condition of pH 1.9～2.5 and tantalum/niobium ratio up to 1/50. If niobium had been present 100 times or more of tantalum, reprecipitation would have been needed. The reciprocal of the specific activity of tantalum pentoxide preciptiate was in a linear relation to the change in the amount of tantalum added. The recommended method gave an accurate result in the determination of tantalum in steel