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Comparison of Techniques for Electrowinning Tungsten from Scheelite.

Authors
Gomes-JM; Uchida-K; Wong-MM
Source
NTIS: PB 205 506 :10 pages
Link
NIOSHTIC No.
10008816
Abstract
Two techniques were investigated for removing cao from scheelite (cawo4) prior to electrolysis. In the first technique, a crude tungstic oxide (wo3) containing 0.15 percent lime (cao) was prepared by digesting scheelite concentrates in hot hydrochloric acid. This oxide was used as cell feed to produce tungsten of 99.9-percent purity. The second technique used a high-temperature, two-phase separation, resulting in the extraction of 99 percent of the wo3 in the halide-tungstate phase, while 90 percent of the cao was retained in the silicate phase. Tungsten of 99.9-percent purity was deposited from the halide-tungsten melt after b2o3 and napo3 were added to form an electrolyte. The two methods were compared with a previously developed technique of depositing tungsten from scheelite concentrate fed directly to the electrolytic cell.
Publication Date
19710101
Document Type
IH; Report of Investigation;
Fiscal Year
1971
NTIS Accession No.
PB-205506
NTIS Price
A02
Identifying No.
RI 7580
NIOSH Division
RERC;
Source Name
NTIS: PB 205 506
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