Russian Journal of Applied Chemistry, 2012, Vol. 85, No. 7, pp. 1077−1082.
Pleiades Publishing, Ltd., 2012.
Original Russian Text © V.Yu. Prokof’ev, N.E. Gordina, A.B. Zhidkova, 2012, published in Zhurnal Prikladnoi Khimii, 2012, Vol. 85, No. 7, pp. 1108−1113.
OF SYSTEMS AND PROCESSES
Investigation of Mechanochemical Synthesis
of Zeolite NaA Made of Metakaolin
in the Mills with Shock-Shear Type of Strain
V. Yu. Prokof’ev, N. E. Gordina, and A. B. Zhidkova
Ivanovo State University of Chemistry and Technology, Ivanovo, Russia
Received July 7, 2011
Abstract—The possibility of obtaining of the NaA zeolite using dry mixture in a mill with a shock-shear type
of strain with anhydrous raw ingredients, metakaolin, aluminium oxide, sodium aluminate was examined. The
optimal time of mechanical activation was found.
Hydrothermal crystallization from solutions, gels
or sols of silicon, aluminum, and sodium compounds
is the traditional method of synthesis of zeolites [1–3].
Templates, which are removed in stages after crystal-
lization, are used for synthesis of zeolite with required
structure. Synthesis with use of metakaolin with a ratio
of Si : Al = 1 : 1, which corresponds to the silica modu-
lus of zeolite NaA, is another common way to obtain
zeolites. Here the stage, which determines the course
of the process, is also a hydrothermal crystallization in
alkaline solution [4–6]. To crystallization a solution of
sodium hydroxide and aluminate is applied, the process
is carried out in several stages with different concentra-
tions of NaOH. In this case, the phase composition will
be governed by the concentration-temperature regime of
the stage of crystallization. The disadvantages of all the
above methods are highly sensitive to the concentration
of reagents, temperature of the processes, as well as a
substantial duration of the process, and the formation of
a large quantity of wastewater.
In [2, 3] the thermodynamics and kinetics of the syn-
thesis of zeolites was analyzed for ﬁ nding out the main
differences of the synthesis of molecular sieves (which
include zeolites) from traditional covalent synthesis. The
framework of zeolite is formed from the TO
(T is atoms of Si, Al, etc.), the main types of bonds in
aggregating are weak ionic, hydrophobic, and hydrogen
interactions. In contrast to the strong covalent these
bonds are kinetically reversible. Another very important
factor is the contribution of enthalpy and entropy to the
value of the Gibbs energy. Thus, in the case of covalent
synthesis ΔH usually dominates while in the synthesis of
zeolite the contributions of ΔH and ΔS are comparable.
Consequently, the success of the synthesis of zeolite
structure prescribed is mainly determined by kinetic fac-
tors, in particular, by synthesis conditions. This suggests
that the mechanochemical synthesis (MCS) of zeolites in
high-energy mills is possible. The advantage of MCS is
the use of dry mixtures to minimize the amount of liquid
phase in the entire synthesis .
Earlier in  MCS of zeolite NaA was described from
aluminum and sodium hydroxides, hydro-silica gel, and
sodium silicate. However, this method is also sensitive
to the mode of synthesis, primarily, to the background of
a raw material. MCS of zeolites from kaolin raw material
is very promising in the mills with the impact-shear load-
ing, which provides no so much grinding the particles as
strain mixing at a cluster level that allows in some cases
changing the direction of the solid-phase synthesis.
The purpose of the study is to examine MCS of zeolite
from kaolin raw material in the dry mixture using
a ring roller vibration mill as an activator.