ELECTROLYTES FOR TUNGSTEN REFINING
375
Electrolysis of Li2WO4–WO3 and K2WO4–WO3 Melts,
Tr. Inst. Elektrokhim., Ural. Nauchn. Tsentr, Akad. Nauk
SSSR, 1974, vol. 21, pp. 61–65.
With decreasing fluoride content, the particle size of
the deposited tungsten rises markedly. The metal
deposited from an electrolyte containing 10–20 wt %
NaF and 10–20 wt % W consisted of lustrous needle-
like dendrites up to 10 mm in length. Increasing the
temperature, W content of the melt, or electrolysis
duration also increases the particle size of the deposit.
4. Baraboshkin, A.N., Saltykova, N.A., and Talanova, M.I.,
Neorganicheskie i organosilikatnye pokrytiya (Inorganic
and Organosilicate Coatings), Leningrad: Nauka, 1975,
pp. 219–227.
5. Zavorokhin, L.N., Baraboshkin, A.N., Plaksin, S.V., and
Kosikhin, L.T., Effect of Gaseous Atmosphere on the
Structure of Tungsten Electrodeposited from Tungstate
Melts, Tr. Inst. Elektrokhim., Ural. Nauchn. Tsentr, Akad.
Nauk SSSR, 1977, vol. 25, pp. 31–35.
The electrolytic tungsten contained Mo 600, Fe
100–200, Si 40, V 1–3, Mg 2, Ti 10–20, Al 1, and
Cr 3 ppm.
The extent of secondary reactions was found to
depend on the grade of the graphite for the facing of the
bath and the arrangement of the anodes in the cell. Ver-
tical anodes ensure better electrolysis conditions than
do horizontal anodes. With vertical anodes, most of the
slime settles on the bottom of the electrolyzer; in con-
trast, with a horizontal electrode, the slime remains on
the surface, contributing to the discharge of tungsten
oxofluoro anions on carbon.
As for the carbon-containing material, note that
dense graphites are less reactive with anodic oxygen.
Particularly high chemical stability is offered by glassy
carbon and dense graphites coated with pyrolytic
carbon.
6. Smithells, C.J., Tungsten, London: Butterworths, 1952,
3rd ed. Translated under the title Vol’fram, Moscow:
Metallurgiya, 1958, pp. 114–123.
7. Fink, M. and Ma, E., Electrochemical Deposition of
Tungsten, J. Trans. Electrochem. Soc., 1943, vol. 84,
pp. 33–40.
8. Balikhin, V.S. and Reznichenko, V.A., Electrorefining
Tungsten, in Metallurgiya molibdena, vol’frama i nio-
biya (Metallurgy of Molybdenum, Tungsten, and Nio-
bium), Moscow: Nauka, 1967, pp. 166–172.
9. Voskresenskaya, N.K., Evseeva, N.N., Berul’, S.I., and
Vereshchetina, I.P., Spravochnik po plavkosti sistem iz
bezvodnykh neorganicheskikh solei (Liquid–Solid Equi-
libria in Anhydrous Inorganic Salt Systems: A Hand-
book), Moscow: Akad. Nauk SSSR, 1961.
REFERENCES
10. Zelikman, A.N. and Meerson, G.A., Metallurgiya red-
kikh metallogv (Metallurgy of Rare Metals), Moscow:
Metallurgiya, 1973, pp. 24–25.
1. Pavlovskii, V.A., Some Electrochemical Properties of
Oxyfluorotungstate Melts, Metally, 1997, no. 5,
pp. 28−31.
2. Pavlovskii, V.A., Structure of Tungsten Electrodeposited
from Oxide–Chloride–Fluoride Melts, Metally, 1998,
no. 3, pp. 18–22.
11. Hammer, W.J., Malmberg, M.S., and Rubin, B., Process
of Producing Tungsten Metal by Electrolysis, J. Electro-
chem. Soc., 1965, vol. 112, no. 7, p. 112.
3. Tarasova, K.P., Nazarov, V.A., and Esina, N.O., Compo- 12. O’Brien, C.J. and Kelly, K.K., Electrorefining Tungsten,
sition and Structure of Cathodic Deposits Produced by J. Am. Chem. Soc., 1957, vol. 79, pp. 80–81.
INORGANIC MATERIALS Vol. 40 No. 4 2004