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Preparation of Ammonium Paratungstate from a Sodium Tungstate-sodium Chloride Phase.
Raddatz-AE; Gomes-JM; Carnahan-TG
MISSING :10 pages
Previous Bureau of Mines research has shown that tungsten ores containing as little as 40 pct (wo3)2- can be processed by a high- temperature molten-salt extraction technique to produce a tungstate- bearing sodium chloride phase with 99 pct w recovery and little impurity contamination. The objective of this work was to demonstrate that the tungstate-bearing sodium chloride phase can be a suitable feed material for preparing ammonium paratungstate (apt) by a modification to the present industrial solvent extraction process. A combined crossflow-countercurrent flow solvent extraction technique to extract tungsten is presented. Apt produced by this new technique contained 88.6 pct (wo3)2- and the following impurities, in percent: mNO2, 0.0007; Moo2, 0.017; P2o5, <0.010; and sio2, 0.012. Implementation of this processing technique would improve tungsten recovery from concentrates and simplify processing operations.
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Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division