TORCRETE MIX OF BASIC COMPOSITION
FOR CONVERTER LINING
E. V. Sidorov,
Yu. N. Kochubeev,
Yu. A. Borisova,
E. V. Murashko,
and N. A. Bosyakova
Translated from Novye Ogneupory, No. 11, pp. 22 – 24, November 2010.
Original article submitted June 24, 2010.
Results are presented for a laboratory study of the substance composition of a periclase-carbon torcrete mix
for restoring a converter lining, comparative methods for testing a torcrete mix under laboratory conditions,
and the main production parameters for a torcrete mix under existing production conditions. Industrial tests
are performed in the converter section of the OAO MMK oxygen-converter workshop. The life of a torcrete
layer is two melts.
Keywords: torcreting, periclase-carbon torcrete mix, adhesion, strength, converter lining.
Semidry torcreting relates to a number of efficient tech-
nologies for servicing the lining of a steel-pouring unit dur-
ing operation. In the oxygen-converter workshop (OCW) of
OAO MMK for hot repair of the most worn zones of a con-
verter lining, i.e. the pouring and tilting cradles, trunion
zones, torcrete mixes of periclase-carbon composition are
used. Since OAO MMK has a natural raw material base for
producing refractories of basic composition, specialists of
the technical services studies the possibility of preparing
torcrete mixes for restoring a converter lining under actual
production conditions, i.e., in the workshop of magnesia-do
lomite refractories (MDRC) of OOO Ogneupor.
In developing torcrete mix compositions under labora
tory conditions the refractory filler used was periclase pow
der or composite material, consisting of fuzed periclase
grains, bonded with flaky graphite by a synthetic resin. In or
der to improve the production and operating properties a
combined binder was added to the composition of the
torcrete mix, consisting of sodium polyphosphate and car
bon-containing components (coal tar high-temperature pitch,
SFP phenolic resin binder, Carbores), and special additions
(silicate materials, bentonite, magnesium sulphate). Along
side the choice of these binder materials and additions the
grain size composition of the torcrete mix was refined.
In the first research stage a study was made of the adhe
sion properties of the compositions developed for degree of
mix sticking with the refractory surface. Tests were carried
out on plates with a cross section of 100 ´ 100 mm
from periclase-carbon refractory. Plates were held at 1200°C
in a laboratory furnace for 1 h, and then the torcrete mix
moistened with water was applied to them. After settling, a
visual estimate was made of the degree of adhesion of
torcrete layer with the plate surface. For comparison a con-
trol mix adopted was series produced composition torcrete
mix PUTMK-3 produced by NPO VOSTIO-Ural used in the
From the results of the first stage of studying 22 devel
oped compositions ten were selected exhibiting a high de
gree of adhesion with the refractory. Compositions with
weak adhesive properties were excluded from further study.
It should be noted that all of the composition selected contain
sodium polyphosphate. In the first stage of laboratory studies
a comparative estimate was made of the quality indices of
laboratory specimens manufactured from torcrete mixes of
control and test compositions in a laboratory hydraulic press
under a pressure of 40 MPa. After pressing specimens were
heat treated in a drying cabinet in an air atmosphere with
maintenance at the maximum temperature of 20°C for
120 min. Coking firing was carried out in a ceramic vessel
with a sealing charge at 1000°C. Results of torcrete mix lab
oratory tests are presented in Table 1.
It was established from the results of laboratory tests that
the behavior of Carbores (compositions 2 and 3), instead of
SFP phenolic resin binder, had a favorable effect on torcrete
mix strength after coking firing, which is an important ser
The content of fine periclase fraction in a charge was
varied from 5.0 to 20.0%. As a result of studies it was noted
Refractories and Industrial Ceramics Vol. 51, No. 6, March, 2011
1083-4877/11/5106-0408 © 2011 Springer Science+Business Media, Inc.
OAO Magnitogorsk Metallurgical Combine, Magnitogorsk, Russia.