CAST-IN-SITU REFRACTORY ARTICLES AND DRY CONCRETE MIXES
WITH ADDITIONS OF CAKED CHROMOALUMINA SPINEL
E. N. Demin
Translated from Novye Ogneupory, No. 12, pp. 11 – 12, December, 2010.
Original article submitted May 4, 2010.
Results of studies of the operational properties of articles made of high-alumina concrete containing oxide
compounds of aluminum and chromium as one of the components are presented. The results demonstrate the
advantage of the study materials as compared with traditional materials.
Keywords: cast-in-situ lining, concrete mix, chromoalumina spinel
At the present time materials based on smelted corundum
and partially with additions of chromoalumina spinel play a
leading role in the area of unmolded refractories. These ma-
terials are highly recommended for use in cast-in-situ lining
of casting ladles as well as in articles, such as clustered units
and blow tuyeres that function in direct contact with the mol-
ten metal and slag. Moreover, these materials are used for the
cast-in-situ roof of electric furnaces and other elements of
thermal sets that require high chemical and thermal shock
stability at temperatures above 1500°C.
In view of our own experience in the fabrication of
cast-in-situ lining and articles made of concrete mixes, as
well as existing trends in countries that are producers of
high-quality refractories, we wish to focus attention on a
high-refractory material that has not been subjected to much
study, i.e., chromoalumina spinel. Over the course of 18
months of study of the operating properties of this material,
in particular, under industrial conditions, a number of con
clusions as regards study compositions based on corundum
and chromoalumina spinel were reached. Comparative metal
and slag stability tests were first performed between the
newly developed mixes of concrete and traditional concrete
mixes produced by well-known foreign and domestic pro
ducers. Optimal variants of the corundum – chromoalumina
spinel composition were then selected for use in the fabrica
tion of dry concrete mixes and articles based on these mixes.
Moreover, other positive properties of these materials, in par
ticular, thermal and chemical stability and enhanced thermal
insulation properties by comparison with magnesia-alumina
spinel, were also taken into account.
In metallurgical processes the role of the gas phase and,
especially, the liquid phase, in reactions between the solid
substances of the lining or between the material of the lining
and the smelt occurring at the refractory – molten metal in-
terface may be extremely significant and even definitive. In a
number of cases, the operating life of refractories and their
resistance to the action of melts of slag and metal differ sub-
stantially from the generally recognized values. Based on re-
cent studies, certain laws were found which, in our view, are
in agreement with the theoretical foundations of the technol
ogy of refractories and their application in casting units.
All the test samples were prepared from appropriate ag
gregates of identical fractions and a given quantity of
high-alumina cement. The thermal treatment regime as well
as the compositions of slag and metal were the same for all
the samples. In determining metal and slag stability, the ma
terials were heated to 1600°C and held for 2 h. Samples ob
tained from corundum compositions with identical content of
magnesia-alumina and chromoalumina spinel possess practi
cally equal slag stability and, depending on the basicity of
the slag, noticeably better indicators by comparison with co
rundum fillers. Moreover, if the basicity of the slag is in
creased, the slag stability of compositions with additives of
either type of spinel was nearly twice as high as that of com
positions with corundum filler. From comparative metal sta
bility tests of samples we arrived at a conclusion that favors
materials with an additive of chromoalumina spinel, in view
of the fact that metal impregnation in these samples is more
than 25% less than that found in all the other test materials.
In the case of thermal stability, the results of the tests demon
strated the advantage of an addition of chromoalumina spinel
Refractories and Industrial Ceramics Vol. 51, No. 6, March, 2011
1083-4877/11/5106-0419 © 2011 Springer Science+Business Media, Inc.
From the proceedings of the International Conference of Metal
lurgists and Refractory Workers (April 22 – 23, 2010, Moscow).
OOO Special Refractory Complex, Yekaterinburg, Russia.