ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 11, pp. 1856 !1859. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + O.I. Kuntyi, V.R. Ivashkin, V.T. Yavorskii, G.I. Zozulya, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 11,
AND CORROSION PROTECTION OF METALS
Electrochemical Processing of WC!Ni Pseudoalloys in Sulfuric
Acid Solutions to Ammonium Paratungstate
and Nickel(II) Sulfate
O. I. Kuntyi, V. R. Ivashkin, V. T. Yavorskii, and G. I. Zozulya
L’vivs’ka Politekhnika National University, Lviv, Ukraine
Received February 26, 2007; in final form, May 2007
Abstract-Electrolysis of a WC3Ni pseudoalloy in aqueous sulfuric acid solutions was studied. A flowsheet
for production of ammonium paratungstate and nickel(II) sulfate is suggested, in which the process solutions
are recycled. The principal electrolysis parameters are presented.
Tungsten is a high-melting metal whose natural
resources are close to exhaustion. Therefore, second-
ary tungsten becomes the principal source of this
metal and its compounds. One of the most promising,
in technological, energetic, and environmental regards,
methods for processing of secondary tungsten is elec-
trolysis of aqueous solutions [13 6]. The variety
of products of the electrochemical transformation
depends on the form of tungsten in secondary raw ma-
terials and on the electrolyte composition. For exam-
ple, tungsten is anodically oxidized in alkaline and
alkaline3ammonia electrolytes to the tungstate ion
from alloys, including those containing tungs-
ten carbide (WC) [1, 2]. In acid electrolytes, WC3Co
is converted to the oxide WO
[1, 335]. Tungsten car-
bides are contained in hard alloys widely used to fab-
ricate special tools, drills, and military equipment.
Therefore, integrated processing of worked-out and
obsolete articles of this kind is a topical area of the
electrochemistry of tungsten.
This study proceeds with an integrated analysis of
the utilization of secondary tungsten with the use
of electrochemical processes [7, 8] and is aimed to
develop process aspects of electrolysis of a poorly
studied WC3Ni system in order to obtain commercial
products, ammonium paratungstate and nickel(II)
Cores of armor-piercing shells 18 and 30 mm in
diameter and 70 mm high, fabricated from a WC3Ni
alloy of compositions (wt %): W 86.4, C 5.8, Ni 7.2,
were used in the study.
The electrolysis was performed in a laboratory
electrolyzer of capacity 5 dm
, schematically shown
in Fig. 1. A 1 M H
solution served as the starting
electrolyte. The cores were placed in a titanium bas-
ket 1. During the electrolysis, the basket was shaken
every 15 min with a vibrator 2, and the electrolyte
) was filtered at regular intervals.
After the electrolysis was terminated, the cores were
cleaned to completely remove tungsten oxides and
Fig. 1. Schematic of the laboratory installation. (1) Tita-
nium basket, (2) vibrator, (3) aluminum cathodes, (4) elec-
trolyzer case, (5) coulometer, (6) filter, and (7) pump.