MANUFACTURING AND EQUIPMENT
PRODUCTION AND SERVICE OF LIGHTWEIGHT REFRACTORY
M. N. Dunaeva
Translated from Novye Ogneupory, No. 8, pp. 13 – 14, August, 2006.
Original article submitted September 8, 2005.
The Pervouralsk Dinas Works has developed mullite-silica vibrocast concrete of grade MKRV. In developing
this grade we took into account all positive and negative aspects of the service of the previously used
mullite-corundum concrete grade MKV. As a consequence, the mechanical strength of the concrete was raised
in the whole service temperature range, its open porosity decreased and, accordingly, its impregnation with
slag and metal decreases, and its heat-insulating properties were improved.
The production of lightweight heat-insulating alumino-
silicate materials uses standard methods: foaming, burning-
out additives, or introduction of a porous filler. The produc-
tion of lightweight materials using burning-out additives or
foaming leads to their substantial shrinkage in firing and low
mechanical strength. In this context, the most promising way
is to use a porous filler with the lowest water absorption,
since in this case one can obtain products with controlled
The Pervouralsk Dinas Works has developed and is pro
ducing mullite-corundum vibrocast lightweight concrete of
grade MKV for lining in the lids of thermal units (ladled).
Concrete here has a dual purpose: apart from its main func
tion of protecting the metal parts of the thermal unit, concrete
solves one of the main problems of thermal power produc
tion: heat conservation and maintaining temperature at a re
quired technological level. Two parameters are essential for
any refractory used as a heat-insulating material: the temper
ature of its protracted service and thermal conductivity. The
achieved thermomechanical and heat-insulating properties of
the developed lightweight concrete make it possible to re
gard it not just as heat-insulating, but heat-insulating-struc
tural material, i.e., it can be used directly in the hot zone of a
thermal unit, improving the lining efficiency, decreasing its
thickness, and reducing heat losses. The application of the
new lightweight refractory concrete provides significant
The main requirements imposed on the lining of thermal
unit lids are as following: the temperature of deformation un-
der loading should be not less than 1450°C; the density and,
accordingly, the weight of the lining should be low (to main-
tain the existing steel structure of the lid); the lining should
have high resistance to thermal shocks to withstand multiple
cycles of heating up to 1400°C and cooling; the lining should
be continuous to facilitate its manufacture.
The traditional heat-insulating refractories (products and
concretes) have a serious drawback, i.e., a low mechanical
strength, which is typical of highly porous materials. There
fore, standard heat-insulating concretes (with apparent den
sity about 1.4 g/cm
) in lid lining may soon become de
stroyed under mechanical impact. The high-density con
cretes (apparent density 2.8 – 3.2 g/cm
) not only have low
heat resistance, but also have a higher thermal conductivity
[above 3.5 W/(m · K)], which requires thicker lining for the
reasons of heat insulation and consequently, a stronger steel
structure of the lid and a more powerful lifting mechanism.
Another disadvantage of heavy concrete lining is its higher
heat capacity and, accordingly, enhanced heat losses.
The new high-temperature heat-insulating material,
namely concrete MKV, has the main properties required for
continuous lining of thermal unit lids: low thermal conduc
tivity, high heat resistance and service temperature, high
chemical resistance, including resistance to alkalis, and cor
Refractories and Industrial Ceramics Vol. 47, No. 4, 2006
1083-4877/06/4704-0199 © 2006 Springer Science+Business Media, Inc.
Pervouralsk Dinas Works, Pervouralsk, Russia.