COMPOSITION OF LADLE SLAG AND REFRACTORY MATERIALS
AND ITS EFFECT ON THE WEAR RESISTANCE OF THE LINING
OF AN RH VACUUM DEGASSER
V. A. Rovnushkin,
É. A. Visloguzova,
S. A. Spirin,
E. V. Shekhovtsov,
V. V. Kromm,
and A. A. Metelkin
Translated from Novye Ogneupory, No. 3, pp. 33 – 36, March, 2005.
Original article submitted December 17, 2004.
The resistance of magnesian spinellide refractories to molten slag attack is studied and effects associated with
the material composition and the microstructure of test specimens are discussed. The mechanisms of corrosion
wear and chemical reactions involved are considered in detail. Slags with a basicity of 1.9 – 2.1 react with
periclase to yield spinel, calcium orthosilicate, and monticellite. To prevent the chemical corrosion of
periclase, sintered periclase or alumina as additions to the slag are recommended for use.
The safe operation of a vacuum degassing vessel is pri-
marily controlled by the stability of the vessel’s refractory
lining. Currently, periclase-chromite refractories are com-
monly used as material for the lining of RH degassers. Prac-
tice has shown that nearly two-thirds of the amount of refrac-
tory material suffers damage form slag erosion (corrosion
wear), and only one-third of the damage is associated with
thermal spalling induced by a sudden heat cycling.
Our goal in this study was to see in what a manner the la
dle slag and refractories of different compositions may affect
the stability of the lining of a vacuum degasser. Therefore
laboratory tests were carried out using industrial slags (sam
pled from a ladle furnace at the Nizhny Tagil Iron and Steel
Works JSC), synthetic slags (prepared by adding pure oxides
to industrial slags), and refractory materials (purchased from
various manufacturers). The chemical composition of indus
trial (Nos.1–4) and synthetic slags is given in Table 1.
Slags Nos.4–6looked hard-caked in appearance; the rest of
the slags easily crumbled (self-crumbling). The chemical
composition of refractories is given in Table 2.
The interaction between refractories and slags was inves
tigated under static conditions. Test specimens with dimen
sions of (40 – 50) ´ (40 – 50) ´ (55 – 85) mm were cut out of
the refractory components; a hole of diameter 14.5 mm and
depth 40 – 45 mm was drilled out in the specimen (to obtain
a kind of crucible); further, test specimens shaped as a cube
with an edge length of 20 mm were cut out. Cubes of type D
(see Table 2 and 3) suffered from cracks and showed little
A crucible specimen with a portion of slag in it was
placed in a Tamman furnace and heated to 1600°C; the mol
ten sample was held for 10 min at this temperature and fur
nace-cooled slowly to 1050°C; next, the crucible was put out
of the furnace and allowed to cool in air.
During cooling, the crucible specimens A and B (held at
1600°C) filled with self-crumbling slag No. 1 and hard-
caked (uncrumbled) slag No. 4 sustained no visible damage,
whereas the crucibles C, D, and E with self-crumbling slags
Nos.1–3 collapsed. For comparison, the crucibles with
uncrumbled slags Nos. 1
(prepared from the precursor
slags Nos.1–3 by adding 0.5% B
) and No. 4 retained
The appearance and physical conditions of test speci
mens were indicative of the extent of damage sustained dur
ing testing. The best conditions were found in refractories A
and B which retained a significant amount of the initial slag
fill. In all the specimens tested, no visible signs of slag ero
sion of the walls and bottom of the crucible could be ob
served, which indicated a sufficient resistance to molten slag
attack of the refractory material. In all the specimens (except
for specimen A), the strength tended to decrease, especially
Refractories and Industrial Ceramics Vol. 46, No. 3, 2005
1083-4877/05/4603-0193 © 2005 Springer Science+Business Media, Inc.
Ural Institute of Metals State Science Center, Ekaterinburg, Rus
sia; Nizhny Tagil Iron and Steel Works JSC.