SPECIFIC ELECTRICAL RESISTANCE OF CARBON MATERIALS
V. V. Buryak,
G. N. Vasil’chenko,
T. V. Chirka,
and S. M. Konstantinov
Translated from Novye Ogneupory, No. 5, pp. 48 – 52, May, 2013.
Original article submitted July 27, 2012.
An analysis of existing data on the specific electrical resistance of carbon materials and on methods used to
study the phenomenon is presented. A plant for the measurement of the specific electrical resistance of granu
lar carbon materials with granulometric composition from 0 to 20 mm in the interval 20 – 1000°C is devel
oped. Data on the specific electrical resistance of a single-component charge with different physical and frac
tional compositions are obtained.
Keywords: specific electrical resistance, carbon materials, coke breeze, recycled single-component charge,
The objective of the present study is to develop a plant
for use in determining the specific electrical resistance of
granular material and to investigate carbon material with
granulometric composition from 0 to 20 mm in the interval
20 – 1000°C.
The evolution of the structure of graphite articles is de-
termined by the raw materials. Carbon materials are not only
the raw material for the manufacture of electrode and graph-
ite products, but also the active resistance of the load of a
graphitization furnace, a reducing agent, and thermal insula
tion. The specific electrical resistance of a coal charge exerts
a significant influence on the uniformity of the distribution
of the electric power in the workspace of a furnace and, con
sequently, on the quality of the product and the energy costs
of the production process.
A. A. Agroskin  made significant contributions to the
study of the specific electrical resistance of coal materials
(brown and black coal), establishing a dependence of the
specific electrical resistance on the particle size of the coke,
pressure, and temperature, Agroskin  presents data on the
specific electrical resistance of coal and slate in the interval
of temperatures from room temperature to 900°C, finding
that it is in the range from 10
These values are approximate and, besides temperature, also
depend on many other factors.
S. P. Shulepov  investigated the specific electrical re-
sistance of a 0.4 – 0.5 mm fraction of petroleum coke at
room temperature; the coke was subjected to preliminary
heat treatment to 1570°C under a 40 bar pressure. A decrease
in the specific electrical resistance from 1.2 ´ 10
2 ´ 10
W·cm is observed over the entire interval of heat
treatment temperatures. The specific electrical resistance re-
mains practically invariant over the interval 300 – 673 K and
equal to that of raw coke, while a sharp decrease in the spe-
cific electrical resistance is observed on the interval
673 – 1073 K; the interval 1073 – 1573 K is characterized by
a weak decrease in the specific electrical resistance and a
transition subsequently to a plateau, which extends to
2273 – 2373 K. Above 2373 K Shulepov noted a second in
tensive drop in the specific electrical resistance related to the
appearance of the three-dimensional structure of graphite.
A. I. Lutkov  presents data on the specific electrical
resistance of a charge made of uncalcined and graphitized
pitch coke of different fractional compositions found under
different pressures. The specific electrical resistance of un
calcined coke in a fraction finer than 5 mm under a pressure
of 2 kPa in the interval 400 – 1300 K varies from 28,000 to
/m, while that of coke in a 5 – 15 mm fraction
in the interval 400 – 2500 K, varies from 5000 to
/m. Trials conducted on graphitized pitch coke
under a 2 kPa pressure in the interval 400 – 1300 K for a
fraction finer than 5 mm demonstrated a decrease in its spe
cific electrical resistance from 21,000 to 6,000 W·mm
and in in pitch coke in a 5 – 15 mm fraction, from 1600 to
Refractories and Industrial Ceramics Vol. 54, No. 3, September, 2013
1083-4877/13/05403-0215 © 2013 Springer Science+Business Media New York
PAO Ukrgrafit, Zaporzh’ye, Ukraine.
National Technical University of Ukraine (Polytechnical Insti
tute), Kiev, Ukraine.