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TitleThe determination of tungsten in ores, concentrates and steels
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorFaye, G H; Guest, R J; McAdam, R C
SourceCanada Mines Branch, Technical Bulletin TB37, 1962, 23 pages, Open Access logo Open Access
PublisherCanada Department of Mines and Technical Surveys
Mediapaper; on-line; digital
File formatpdf
Released1962 01 01; 2017 03 28
AbstractRapid and reliable procedures, all of which utilize a spectrophotornetric finish, have been developed for the determination of tungsten in ores, concentrates and high-alloy steels. The proposed procedures have been applied to a variety of samples, including N.B.S. steel samples, covering a wide range of tungsten concentrations, and the results agree with those obtained by established but less convenient methods. Ores and concentrates are decomposed by either an acid attack or a pyrosulphate fusion depending upon the nature of the sample; steels are dissolved in an acid solution. In the proposed procedures, tungsten is first reduced with stannous chloride under controlled conditions of temperature and acidity, and then complexed with thiocyanate. Tungsten may be determined directly by measuring the optical density of the coloured complex at 400m11, or when interfering coloured substances are present, the complex may be extracted into a suitable organic solvent and its optical density measured. The optimum working range in the proposed method is from 0.05 -1.00 mg of tungsten in. the aliquot taken for analysis. The effect of a number of possible interfering is shown. Molybdenum, when present in conjunction with iron, causes high results, but this interference can be overcome by a prior extraction of the iron from a chloride medium with isopropyl ether.

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