Semimicrodetermination of combined tantalum and niobium with selenous acid

Analytical Chemistry
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Abstract

Tantalum and niobium are separated and determined gravimetrically by precipitation with selenous acid from highly acidic solutions in the absence of complexing agents. Hydrogen peroxide is used in the preparation of the solution and later catalytically destroyed during digestion of the precipitate. From 0.2 to 30 mg., separately or in mixtures, of niobium or tantalum pentoxide can be separated from mixtures containing 100 mg. each of the oxides of scandium, yttrium, cerium, vanadium, molybdenum, iron, aluminum, tin, lead, and bismuth with a single precipitation; and from 30 mg. of titanium dioxide, and 50 mg. each of the oxides of antimony and thorium, when present separately, with three precipitations. At least 50 mg. of uranium(VI) oxide can be separated with a single precipitation when present alone; otherwise, three precipitations may be needed. Zirconium does not interfere when the tantalum and niobium contents of the sample are small, but in general, zirconium as well as tungsten interfere. The method is applied to the determination of the earth acids in tantaloniobate ores.
Publication type Article
Publication Subtype Journal Article
Title Semimicrodetermination of combined tantalum and niobium with selenous acid
Series title Analytical Chemistry
DOI 10.1021/ac60151a014
Volume 31
Issue 7
Year Published 1959
Language English
Publisher ACS Publications
Description 3 p.
First page 1270
Last page 1272
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