THERMAL CONDUCTIVITY OF CARBON-BASED MATERIALS
S. V. Kutuzov,
G. N. Vasil’chenko,
T. V. Chirka,
and E. N. Panov
Translated from Novye Ogneupory, No. 1, pp. 43 – 48, January, 2013.
Original article submitted June 14, 2012.
Existing data on the thermal conductivity of carbon materials is analyzed together with methods of using this
information. A unit was developed for measuring the thermal conductivity of carbon-based bulk materials of
the 0 – 10-mm fraction in the temperature range 100 – 1000°C. Data is obtained on the thermal conductivity
of a one-component charge material of different granulometric and material compositions.
Keywords: thermal conductivity, carbon materials, coke fines, recycled one-component charge material, unit
for determining the thermal conductivity of carbon materials.
The goals of the project being discussed in this article
were to design and build a unit that can be used to determine
the thermal conductivity of bulk materials and to study a dis-
persed carbon-based material of the 0 – 10-mm fraction in
the temperature range 100 – 1000°C.
To be able to perform certain industrial operations, fac-
tory equipment needs to be provided with high-temperature
heat-insulating materials that can perform under appreciable
pressures and thermal stresses and are designed to withstand
thermal and mechanical loads. The material of the greatest
interest in this regard is coal coke, which is now in wide use.
Fine coal coke smaller than 10 mm (coke fines) is used as a
refractory covering and heat-insulating material in roasting
furnaces and furnaces used to make graphite electrodes .
The thermophysical properties and granulometric composi
tion of such covering and insulating materials have a signifi
cant effect on the graphitization of the semifinished products
and the uniformity of the temperature distribution in the fur
The quality of graphitized electrodes is related to the
properties of the heat-insulating materials which are used .
Those materials must satisfy such requirements as high elec
trical resistivity, low thermal conductivity, and satisfactory
porosity. The temperature field over the cross section of the
furnace can be made uniform by reducing the thermal con
ductivity of the insulating material. The use of optimum in
sulating and covering materials can reduce unit energy costs
by 6% (by 300 kWh/ton).
SURVEY OF LITERATURE SOURCES
The literature contains a fairly large amount of informa-
tion on the thermophysical properties of carbon-based mate-
rials. Nevertheless, an analysis showed that it provides only
general descriptions of the character of the thermal-conduc-
tivity curves of carbon materials as a function of temperature
and granulometric composition. A. A. Agroskip made a sig-
nificant contribution to the study of carbon materials, espe-
cially coal coke. In  he reported on the thermal conductiv-
ity of carbon-based bulk materials used in the baking of elec
trodes. These materials consist of ground graphitized and
foundry-grade coke, as well as recycled wastes generated in
the repeat use of graphitized coke. The materials are of the
0 – 2-mm fraction. Bulk density is 672 kg/m
foundry-grade coke, 560 for graphitized coke, and 606 kg/m
for the recycled wastes. The thermal conductivity of all of
these bulk materials increases almost linearly with tempera
ture. The values obtained for thermal conductivity when deter
mined within the range 100 – 800°C are 0.249 – 0.542 W/(m·K)
for foundry coke, 0.321 – 0.623 W/(m·K) for graphitized
coke, and 0.246 – 0.541 W/(m·K) for recycled wastes. Gra
phitized coke has the highest conductivity, despite having the
lowest bulk density. The results show the effect of granulo
metric composition on the conductivity of bulk covering and
filling materials composed of foundry coke and graphitized
coke. Here, we divide the materials into the following groups
based on coarseness, mm: 0 – 0.5, 0.5 – 1, 1 – 2, 2 – 3, 3 – 4,
4 – 5, 5 – 6, and 6 – 8. The test results are for the range
100 – 600°C and show a general tendency for thermal con
ductivity to increase with an increase in grain size through
out the entire temperature range. For example, at 600°C the
Refractories and Industrial Ceramics Vol. 54, No. 1, May, 2013
1083-4877/13/05401-0039 © 2013 Springer Science+Business Media New York
PAO “Ukrgrafit”, Zaporozhe, Ukraine.
Kiev Polytechnic Institute, National Technical University of the
Ukraine, Kiev, Ukraine.