PERVOURAL’SKII AND KAREL’SKII QUARTZITES
FOR THE LINING OF CRUCIBLE-TYPE INDUCTION FURNACES
V. V. Shchiptsov,
V. A. Perepelitsyn,
E. E. Grishenkov,
V. P. Enenko,
and A. S. Zavertkin
Translated from Novye Ogneupory, No. 6, pp. 37 – 45, October, 2002.
Requirements placed on the quartzite-based lining of crucible-type induction furnaces are discussed. The
properties of Pervoural’skii and Karel’skii quartzites (P- and K-quartzites) are studied. Mineral impurities (in
particular, mica) and their effect on properties of quartzite mixtures are considered. Industrial tests show that
the fine-grained, predominantly intergranular mica is mainly responsible for the high wear resistance of
K-quartzites. A characterization of the Metchangjarvi quartzite deposit is given and its commercial potential
for production of refractory materials is discussed.
Trends in the development of world metallurgy has
shown that the melting technology based on the use of cruci-
ble-type induction furnaces has a number of economical and
technical advantages, in particular, the inexpensive and eas-
ily replaceable refractory lining.
Crucible-type induction furnaces for melting iron, cer-
tain steels, and a range of nonferrous alloys in Europe and
countries of the former Soviet Union use mostly the acidic
quartzite-based lining. The reason for this is that one of the
essential features required of the lining of crucible furnaces
is the constancy of volume or the least possible (within 1%)
volume expansion at the operating temperature and the
buildup of an intermediate weakly sintered (unconsolidated)
layer that prevents crack growth towards the inductor.
Quartzite-based materials comply with these requirements.
An exceptionally useful property of silica that makes
quartzites irreplaceable materials for the lining of crucible
furnaces is its polymorphism. Transition of b-quartz to less
dense modifications with an increase in volume makes it
possible to compensate for shrinkage of the lining during
sintering and provide conditions, in the intermediate temper
ature range, for an expansion zone. Quartzites that retain
strength and density during the quartz inversion are the only
materials suited for the lining of induction furnaces .
Further requirements placed on the quartzite lining of
crucible furnaces are:
– resistance to crack growth under conditions of signifi-
cant temperature stresses associated with a high temperature
– thermal stability under conditions of temperature fluc-
tuations arisen from the charging of a cold mixture or from
– low thermal linear expansion coefficient (a factor to a
large extent responsible for heat stability);
– high resistance to fluid metal and slag; the least possi
– refractoriness of the lining should not exceed apprecia
bly the operating temperature of the lining (not higher than
150 – 200°C); the lining should exhibit a reasonably low sin
– sufficient mechanical strength allowing the crucible to
sustain the load due to molten metal and heavy burden;
– constancy of chemical and phase composition .
Dry mixtures based on quartzites and quarts sands that
contain sintering additions (boric acid, boric anhydride) and
additions for improving metal and slag resistance (Cr
rare-earth metal oxides) generally comply with these require
ments. In Russia, the basic precursor material for preparing
mixtures is the Pervoural’sk quartzite (henceforth P-quartzite
for brevity) recovered from the Gora Karaul’naya deposit
(GK-deposit). The only manufacturer of quartzite powders is
the Dinur Joint-Stock Co. (city of Pervoural’sk).
Refractories and Industrial Ceramics Vol. 44, No. 1, 2003
1083-4877/03/4401-0067$25.00 © 2003 Plenum Publishing Corporation
Institute of Geology, Karelian Science Center, Russian Academy
of Sciences, Russia; Eastern Institute of Refractories Research
and Production Association Joint-Stock Co., Ekaterinburg, Rus
sia; Intermet Engineering Joint-Stock Co., Moscow, Russia;
AMO-ZIL Moscow Automobile Society, Moscow, Russia.