INORGANIC SYNTHESIS AND INDUSTRIAL
Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 4, pp. 565−571.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © L.A. Zemnukhova, G.A. Fedorishcheva, E.D. Shkorina, T.A. Kaydalova, N.N. Barinov, 2011, published in Zhurnal Prikladnoi Khimii,
2011, Vol. 84, No. 4, pp. 529−535.
Amorphous Silicon Dioxide
from Waste of Ferroally Production
L. A. Zemnukhova, G. A. Fedorishcheva, E. D. Shkorina,
T. A. Kaydalova, and N. N. Barinov
Institute of Chemistry, Far East Branch, Russian Academy of Sciences, Vladivostok, Russia
Far Eastern Geological Institute,Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
Received June 29, 2010
Abstract—The optimum conditions for the formation of amorphous silicon dioxide from wastes formed in
ferroalloy production containing more than 99% of the main substance were determined and its physicochemical
properties were studied.
At the high-silicon alloy producing plants the bulk
of wastes is in the form of a siliceous dust, which is
currently used for producing commercial product,
microsilica (MS). Total production of microsilica in the
world is more than 240 000 tons yearly; in Russia, it
is also produced [1–3]. The content of silica in it does
not usually exceed 92%, but amorphous state of the
substance makes this product suitable for the use in
construction industry, including overseas [4, 5]. Large
volumes of wastes formed in ferroalloy production
attract attention of researchers as a raw material for the
preparation of amorphous silicon dioxide, which is less
contaminated with impurities  and has a wide range
of applications, depending on its physical and chemical
characteristics [7, 8].
In the study, the conditions of the microsilica
treatment to form high-purity amorphous silica are
determined and its physicochemical characteristics are
Object of study was a ﬁ nely disperse commercial
microsilica of dark grey color produced at the Open
Joint-Stock Company “Kuznetskie ferrosplavy” .
The concentration of silicon in this sample was found
gravimetrically . Presence of other elements was
determined by spectral (PGS-2 specrtometer) and
atomic absorption analysis (АА-780 Nippon Ihrrell Ash
spectrophotometer, Japan). The amount of absorbed
water was determined on a Q-1000 derivatograph
(Hungary), the mass loss in calcination at 1000°С (c.l.)
was determined on heating a sample in a mufﬂ e furnace.
The phase composition of substances was studied by
the X-ray phase analysis (XPA, Bruker D8 ADVANCE
radiation, EVA software, powder
diffraction ﬁ le PDF-2). The IR absorption spectra of
powders (suspensions in vaseline oil) were recorded in
the range 400–4000 cm
on a Shimadzu Prestige-21
IR Fourier spectrophotometer (Japan) [10–12]. The
photomicrographs of particles were obtained on
a EVO-50 XVP LEO scanning electron microscope
(Germany), the speciﬁ c surface area S
of the substance
was measured by the procedure described in , with
methylene blue. The bulk density of the substance was
determined as the ratio of the sample mass to its volume
by the standard procedure . The results obtained are
collected in Table 1 and Figs. 1a, 2a, 3.1.
The concentration of the main substance, silicon di-
oxide, in the initial microsilica does not exceed 89.3 wt
% (Table 1). The XPA of the sample revealed amorphous
and crystalline phases (Fig. 1a). To the amorphous phase
belongs a diffuse reﬂ ection in the range 2θ = ~18–30°.
The following crystalline compounds were identiﬁ ed:
), silicon carbide (SiC), silicon (Si),
and maghemite (Fe
). The absorption bands in the IR