SPECTROCHEMICAL DETERMINATION OF SMALL CONCENTRATIONS OF NIOBIUM AND TANTALUM IN ROCKS

A spectrochemical method for the determination of small quantities of niobium and tantalum in rocks was developed including a preliminary chemical concentration with the use of phenyl-arsonic acid for the precipitation of the elements together with titanium followed by a spectrographic analysis of the products of concentration. The determination of niobium and tantalum is possible when their concentration in rocks is not less than 5 x 10/sup -5/%; the probable experimental error is about 7% for niobium and 9% for tantalum. (auth)