1070-4272/05/7807-1043C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 7, 2005, pp. 1043!1047. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 7,
2005, pp. 1065!1069.
Original Russian Text Copyright + 2005 by Eremina, Avvakumov, Zelinskii.
AND INDUSTRIAL INORGANIC CHEMISTRY
Properties of a Fireproofing Formulation Based
on Liquid Glass and Mechanically Activated Aluminum Oxide
N. V. Eremina, E. G. Avvakumov, and V. Yu. Zelinskii
Institute of Solid-State Chemistry and Mechanochemistry, Siberian Division, Russian Academy of Sciences,
Korund Ltd., Ust’-Kamenogorsk, Kazakhstan
Received November 17, 2004; in final form, April 2005
Abstract-Moistening of filler particles with binder, curing, and high-temperature synthesis were studied
in a liquid-glass formulation based on aluminum oxide. Selected kinetic parameters of these processes were
determined. The influence exerted by the phase composition and mechanical activation on the adhesion, yield
of the synthesis product, and basic properties of the formulation were analyzed.
Liquid-glass formulations (LGFs)containig mineral
fillers and some functional additives creating a com-
bustion-inert atmosphere are used as fireproofing ma-
terials . The most important properties of LGFs:
long working life, good adhesion, and high fireproof-
ing efficiency, are determined by processes that in-
volve the binder and filler, including synthesis of
phases in the high-temperature zone at the seat of fire.
One of the main ways to affect the properties of an
LGF is to change the chemical activity of fillers .
However, the expected result may vary between dif-
ferent properties. Raising the activity of a filler im-
proves the fire-proofing efficiency, but, as a result
of coagulation, impairs the adhesion and service life
of an LGF. Mechanical activation (MA) is commonly
used as an effective method for enhancing the reactiv-
ity of powdered media, but it virtually has not been
studied at all as applied to LGF .
The aim of this study was to examine the adhesion
properties of a liquid-glass formulation containing
mechanically activated Al
in stages of moistening
and curing. The products formed in its thermal treat-
ment in the range 20031000oC were determined.
The choice of Al
was governed by the strong
variation of the chemical activity of this oxide with its
phase composition. Alumina of G-00 brand [75 wt %
g-phase and a-phase, GOST (State Standard) 13 078],
was taken for MA. The powder was activated in a
planetary-centrifugal mill with rubberized drums and
corundum balls, at a material : balls ratio of 1 : 3
and a rotary acceleration of 18g. Alumina of GK
brand, containing 100 wt % a-phase (GOST 30559),
served as a chemically inert filler; and Al(OH)
(GOST 11841), as the most active filler passivated by
annealing at 500, 700, 900, and 1000oC, which was
accompanied by formation of transient Al
of g-, c, k-, and q-types . According to the results
of an X-ray phase analysis, the phase composition of
the annealing products varied as follows: 500oC, alu-
minum hydroxide and trace amounts of the g-phase;
700oC, g-phase and trace amounts of the c-phase;
900oC, c-phase and trace amounts of the k- and
q-phases; and 1000oC, k- and q-phases. To eliminate
any influence of the dispersity of a filler in LGF, the
powder fraction obtained by sedimentation in water
was used. According to the results of a granulometric
analysis on a Sedigraf 5000 ET instrument, the frac-
tion contained the following types of particles: 33
5 mm, up to 15 wt %; 5310 mm, up to 73 wt %; and
10315 mm, the rest.
A sodium liquid glass with a silica ratio of 2.8 and
density of 1.34 g cm
was taken as a binder. The
choice of the chemical composition of the binder was
governed by the possibility of maximal accumulation
of water in the hydration environment of the cation.
It has been established that the fraction of crystalliza-
tion-bound water for Na
considerably exceeds that
. Intensive dehydration in the temperature
range 1503450oC must markedly raise the porosity of
LGF in the initial stages of a fire, which improves
the fireproofing efficiency of a coating.
The formulation based on liquid glass contained
48 vol % binder and 52 vol % filler. The composition
was chosen empirically, as providing the highest