00000nam 2200000za 4500 9.841312 CaOODSP 20221107152045 cr ||||||||||| 170809s1968 onc ob f000 0 eng d CaOODSP eng eng fre n-cn--- M34-20/103E-PDF M34-20/103 Vezina, J. A. Improvement of a continuous process for the production of tungstic trioxide from scheelite [electronic resource] : precipitation and removal of iron with ammonium and magnesium chlorides / J.A. Vezina and W.A. Gow, Extraction Metallurgy Division. Ottawa : Queen's Printer, 1968. iv, 13 p. Technical bulletin ; TB 103 Cover title. "November 1968." Digitized edition from print [produced by Natural Resources Canada]. Includes bibliographical references. “Test work was carried out to remove iron and other impurities from a sodium tungstate solution. This constituted an improvement to the process previously developed at the Mines Branch for refining Canadian scheelite concentrates of grades as low as 41 per cent WO3. In this test work, by making the intermediate sodium tungstate solution ammoniacal and adding specific quantities of magnesium chloride and ammonium chloride, the iron concentration was decreased from 0.33 to 0.007 gram Fe per litre. When the basic process was modified to include this iron-removal step, it was capable of producing ammonium paratungstate of a chemical purity suitable for the production of tungsten metal. The additional cost involved in the precipitation of the iron from the process circuit was $0.023 per pound of tungsten obtained"--Abstract, p. i. Includes abstract in French. gccst Chemicals gccst Processing Gow, W. A. Canada. Natural Resources Canada. Canada. Mines Branch. Technical bulletin (Canada. Dept. of Energy, Mines and Resources. Mines Branch) TB 103 (CaOODSP)9.834857 PDF 1.57 MB https://publications.gc.ca/collections/collection_2017/rncan-nrcan/M34-20/M34-20-103-eng.pdf 299989