PREPARATION OF POROUS CERAMIC MATERIALS
BASED ON WOLLASTONITE USING SILICON-CONTAINING COMPONENTS
A. T. Volochko,
K. B. Podbolotov,
and A. A. Zhukova
Translated from Novye Ogneupory, No. 5, pp. 24 – 29, May 2011.
Original article submitted January 14, 2011.
Results are provided for evaluation of the possibility of preparing porous ceramic materials using synthetic
wollastonite and silicon-containing components by chemical pore formation. The mechanism of pore forma-
tion, and also chemical processes during material drying and firing are studied. The physicochemical proper-
ties and microstructure of the material obtained are studied.
Keywords: porous ceramic material, wollastonite, silicon-containing components, chemical pore formation
Wollastonite is a natural calcium silicate with the chemi-
cal formula CaSiO
. It is white in color with gray or brown
tints, distinguished by chemical purity, and it contains an in-
significant amount of harmful impurities in the form of man-
ganese, iron and titanium oxides. For wollastonite there is a
typical acicular crystal structure, which determines its main
use as a micro-reinforcing filler. In view of the worsening
ecological situation it should be noted that wollastonite is a
replacement for such carcinogenic substances as asbestos,
and talc. Until recently asbestos heat insulation materials
have been used within Belorussia in all metallurgical enter-
prises. During their prolonged operation there is breakdown,
as a result of which asbestos dust appears in production ar-
eas, which is a source of oncological pulmonary diseases for
humans. In this connection, replacement of asbestos by more
ecological heat insulation materials is an important task.
In order to resolve the problem different technologies are
used for creating porous materials for engineering purposes
using the method of self-propagating high-temperature syn-
thesis (SHS), gas formation in the hardening stage followed
by heat treatment, and introduction of combustible additions
during synthesis, etc. Recently new refractory, especially
light, SHS concretes have been developed, prepared by cold
expansion, followed by heat treatment and SHS. The objects
are prepared by pouring previously prepared liquid-binder
slip, of the required composition and consistency, into spe-
cial dismountable molds in order to obtain finished objects of
different configuration, i.e., bricks, blocks, bars, and plates.
The porous objects have an apparent density of 200 – 600 kg/m
thermal conductivity of 0.12 – 0.35 W/(m·K), with an ulti-
mate strength in compression of 1.0 – 4.0 MPa. However, for
occurrence of SHS it is necessary to use a reducing agent in
the form of metal (aluminum and its alloys), which is not al-
Studies are known devoted to preparing wollastonite
lightweight objects, which have found extensive use in the
aluminum industry as a lining for troughs, in the manufacture
of casting equipment during pouring of aluminum, and also
for heat insulation of eletcrolyzers, melting furnaces and
mixers of the aluminum industry [1 – 5]. In the A. S.
Berezhnyi UkrNIIO technology has been developed for
wollastonite lightweight objects with an apparent density of
and with an ultimate strength in compression of
3.6 MPa, prepared by solid-phase synthesis from calcium
and silicon-containing materials [6 – 8]. Use of wollastonite
makes it possible to prepare porous objects with quite high
strength due to its structural features; the application temper-
ature for these objects is not above 1200°C.
This work is devoted to preparing new heat insulation
materials based on wollastonite by chemical pore formation
using silicon-containing components.
Refractories and Industrial Ceramics Vol. 52, No. 3, September, 2011
1083-4877/11/05203-0186 © 2011 Springer Science+Business Media, Inc.
GNU Physicomechanical Institute of NAN Belorus’, Minsk,
Belorussian State Technological University, Minsk, Belorus’ Re