00000nam 2200000za 4500 9.840315 CaOODSP 20221107151819 cr ||||||||||| 170725s1967 onc ob f000 0 eng d CaOODSP eng n-cn--- M38-8/34E-PDF M38-8/34 Vezina, J. A. A process for preparing tungstic trioxide of high purity from a Canadian scheelite concentrate [electronic resource] / J.A. Vezina and W.A. Gow, Extraction Metallurgy Division. Ottawa : Queen's Printer, 1967. p. 1418-1422 Reprint series ; RS 34 Cover title. "Reprinted from The Canadian Mining and Metallurgical Bulletin, December 1966, Vol. 59, No. 656, pp. 1418-1422." Historical publication digitized from print 2017 [by Natural Resources Canada]. Includes bibliographical references. "A new process for treating scheelite for the production of tungstic trioxide is described. The novelty of the process resides in that an ion-exchanger is used to convert sodium tungstate to either ammonium tungstate or tungstic acid. The process consists of a conventional hydrochloric acid leach of the scheelite concentrate, and the dissolution of the impure tungstic acid thus produced with sodium hydroxide at pH 8. The sodium tungstate solution is clarified and passed through a column of Dowex 50Wx8 ion-exchange resin to exchange the sodium ions for either hydrogen or ammonium ions, both being suitable. The tungsten-bearing column effluent is evaporated to crystallize the tungsten as ammonium tungstate; the crystals are washed with nitric acid and water and decomposed by heat to produce tungstic trioxide of high purity. Ninety-six per cent of the tungsten in the concentrate may be recovered as tungstic trioxide (WO3), and the reagents consumed are 0.7 g HC1, 0.41 g NaOH and either 1.73 g NH4CI or 225 g HCl per gram of tungsten"--Abstract, p. 1418. gccst Chemicals gccst Processing Gow, W. A. Canada. Natural Resources Canada. Canada. Department of Energy, Mines and Resources. Canada. Mines Branch. Reprint series - Dept. of Energy, Mines and Resources, Mines Branch ; RS 34 (CaOODSP)9.834843 PDF 1.98 MB https://publications.gc.ca/collections/collection_2017/rncan-nrcan/M38-8/M38-8-34-eng.pdf 300113