1070-4272/03/7608-1234 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 8, 2003, pp. 1234!1237. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 8, 2003,
Original Russian Text Copyright + 2003 by Krylov, Lugovskaya, Anufrieva, Krylova.
AND ION-EXCHANGE PROCESSES
Composition and Physicochemical Properties of Schungite
Sorbent as Influenced by Thermal Treatment
I. O. Krylov, I. G. Lugovskaya, S. I. Anufrieva, and A. V. Krylova
Fedorovskii Russian Institute of Mineral Raw Materials, Moscow, Russia
Mendeleev Russian University of Chemical Engineering, Moscow, Russia
Received July 26, 2002; in final form, February 2003
Abstract-The chemical composition, specific surface area, and pore structure of a schungite sorbent were
studied as influenced by the conditions of thermal treatment.
It is known  that schungite rocks from Karelia
are used as sorbents in treatment of waste and reused
water. Schungite rocks consist of various minerals
(e.g., quartz, aluminosilicates, carbon, etc.) and show
promise as complex sorbents combining the properties
of carbon and silicate materials.
The sorption properties of schungite rock can be
improved by thermal treatment . However, data on
how the heating conditions affect the schungite prop-
erties are scarce, the possible modes of thermal treat-
ment for schungite modification have not been sub-
Samples of schungite sorbents (SSs) were prepared
by crushing and sieving a schungite rock from Zazho-
ginskoe deposit to size grade of 2.530.5 mm. The ther-
mal transformations were studied in air in the 203
1000oC temperature range using a 3434-S (model 907)
derivatograph (10 deg min
heating rate, 50-mg sam-
ple weight, platinum crucibles, and a-Al
The thermal oxidative treatment of the schungite
sorbent was performed at three temperatures corre-
sponding to the characteristic points in the DTA curve
of the initial sample (Fig. 1): maximum of the exo-
thermic peak at 528oC and two inflection points of
the curve at 411 and 750oC at which structural trans-
formations of the material occur. As seen from the TG
curve, a pronounced weight loss by the material be-
gins at about 500oC.
The thermal treatment of the SS samples (353 40 g)
were performed in a muffle furnace in air for 1, 2, 3,
4, and 8 h. The rate of heating of the muffle furnace
to a given temperature was 5 deg min
; the temper-
ature was controlled with an accuracy of +3oC.
The treated samples are denoted as SS-411, SS-528,
and SS-750, in accordance with heat treatment tem-
Data on the effect of thermal treatment on the
chemical composition of schungite sorbents are listed
in Table 1.
As seen, the content of carbon in the samples de-
creases with increasing temperature, whereas the con-
tent of silicon and aluminum oxides grows. We as-
sume that the rapid weight loss at temperatures higher
than 500oC (Fig. 1) is due to burning-out of carbon,
whose content decreases by a factor of 1.4 and 3.4
for SS-528 and SS-750, respectively.
Fig. 1. TG and DTA curves of the initial schungite sorbent:
(Dm) weight change and (t) time.