A STUDY OF THE THERMAL CONDUCTIVITY
OF NEW REFRACTORY CONCRETES WITH POROUS FILLERS
D. F. Nurgaliev,
V. M. Sizyakov,
and V. A. Utkov
Translated from Novye Ogneupory, No. 7, pp. 25–26, July, 2014.
Original article submitted May 20, 2014.
An experimental plant for quick comparison of the thermal conductivity of new refractory lining and other
materials is proposed. It is found that whitened waste slurry generated in the production of aluminum oxide
and distinguished by elevated porosity may be used as the fillers of refractory thermal insulating materials.
Keywords: thermal conductivity, refractory concrete, waste slurry, laboratory plant
The problem of economizing on the use of natural ther-
mal insulating materials is especially critical in the northern
latitudes of Russia where overconsumption of heat-transfer
agents in furnace equipment reaches 30% due to the fact that
thermal insulating refractories are so expensive. Heat losses
may be markedly reduced with the use of new inexpensive
thermal insulating materials in the structural furnace indus-
try. Most thermal insulating materials are distinguished by
elevated porosity. Since refractory thermal insulating materi
als are used in industry at high temperatures, they must have
a high melting point. Waste nepheline slurry generated in the
production of aluminum oxide and belonging to the system
Ca–Si–Al–Fe–O possesses such a temperature. Its melting
point is 1600°C. Refractory concrete samples are obtained
from moist nepheline slurry and brand 400 cement. The ther
mal conductivity of refractory concrete of the most common
composition of a mixture consisting of refractory cement
(two parts) and quartz sand (three parts) has been adopted as
A laboratory plant (Fig. 1) that comprises a horizontal
heating element and a system of thermocouples was created
for the studies. One of the thermocouples measures the tem
perature of the heating surface while the other two monitor
the passage of a heat wave into the test samples. The
thermocouples are mounted in specially prepared holes and
function in a differential regime, measuring the difference in
the temperatures at two points of the sample situated along a
vertical line perpendicular to the heated surface. The depth of
immersion in the sample is equal to one-half its thickness.
The rate of increase of the temperature at the test points
of the sample and the temperature difference between these
points are adopted as measures of the rate of travel of the
heat wave. The lesser the rate of heating of the upper point
and the greater the temperature difference between the check
points, the lower is the thermal conductivity of the material.
The results are shown in Fig. 2. The coefficient of thermal
Refractories and Industrial Ceramics Vol. 55, No. 4, November, 2014
1083-4877/14/05504-0304 © 2014 Springer Science+Business Media New York
FGAOU VPO Gornyi National Minerals and Raw Materials Uni
versity, St. Petersburg, Russia.
Fig. 1. Diagram of laboratory plant for use in determining the ther
mal conductivity of refractory concretes: 1) heating element;
2) sample; 3) thermal insulating wall; 4) measuring device.