STUDY OF MINERAL AND PHASE COMPOSITIONS
OF A FURNACE LINING AFTER MELTING CRUDE FERRONICKEL
V. V. Sharapova
Translated from Novye Ogneupory, No. 10, pp. 39 – 41, October 2010.
Original article submitted August 13, 2010.
Combined methods are used to study the lining of a ferroalloy furnace after service. It is established that
periclase-chromite refractories are subject to chemical corrosion. Readily melting silicates and a metal phase
form in a furnace lining, and reducing processes occur with participation of silicon, chromium and nickel
Keywords: chemical and mineral compositions, lining, periclase-chromite refractories, sub-oxides.
In heating units for preparing different grades of ferro-
alloys refractory materials are used that resist the action of
high temperature and reaction with molten alloys. In many
cases the potential of a metallurgical process is governed by
presence of appropriate refractory material with a required
life. In choosing refractories it is necessary to consider such
properties as chemical behavior, resistance to the action of
slags, molten metals, and also against reduction and oxida-
tion, material melting temperature, and a capacity to be con-
verted into a solid state.
Resistance and melting temperature determine the over
all suitability of a refractory material. This resistance de
pends mainly on its chemical and mineral compositions. A
marked effect on the refractory properties of an object is the
binding addition. The question of mineral content of a refrac
tory material is also important.
Results are provided in this article for a study of the state
of a worn out lining of periclase-chromite refractory for fur
nace RTP-2 after melting crude ferronickel. For the
three-phase furnace RTP-2 the working lining used is refrac
tory PKhSP (GOST 10888). This furnace lining is as follows:
a chamotte crumb is applied to the casing of the hearth for
levelling the surface. Five layers of chamotte refractory are
laid on the crumb, above which there is vertical placement of
two rows of refractory PKhSP with a height of 300 mm for
the lower row and 360 mm for the upper (“firing”) row. The
walls of the metal bath were laid from four rows of refractory
PKhSP to a height of 600 mm.
Specimens of worn out lining were studied after two
years of furnace operation. The samples studied were taken
from the outer row (adjacent to the casing) of lining objects
in the area of metal break through: 1) from the residue of an
object, 2) from intact refractory.
Examination of the area of furnace burn-through showed
that molten metal destroyed the upper row of PKhSP
refractories and burned through the furnace casing. The min-
eral and phase compositions of the sample of the worn out
lining were studied by petrographic analysis in reflected and
transmitted light in MBI-6 and MIN-8 microscopes at mag-
nifications of 210 and 1425. Study of the metal phase was
carried out using x-ray microanalysis in an MS-46 Cameca
The samples (specimens) selected from the worn lining
of the metal bath of furnace RTP-2 were gray-green in color,
dense, and stony. Over the surface and within specimens
there is a metal phase in the form of dispersed beads and
coarse inflows with a size up to 6 mm. The amount of metal
phase in lining samples increases over the direction into
specimens. In samples, taken in the region of the metal bath,
there is a slag skin with a thickness from 6 to 25 mm.
A study of periclase-chromite objects after service from
zones of a metal bath and in the area of break-through of
melt showed that they are enriched in metal phase. The dis
tribution of metal phase in samples is uneven. Sometimes the
metal content reaches 64%. In addition, specimens are en
riched with silicate component. A zonal nature, i.e., the dis
tribution in the working, transition, and least changed zones
from the inner working wall of the lining to the outer wall is
not observed in the part of the lining selected. Chemical anal
ysis established that a specimen from melt break-through
zone contains, wt.%: Cr
13.29, MgO 58.46, Ni
Refractories and Industrial Ceramics Vol. 51, No. 5, January, 2011
1083-4877/11/5105-0374 © 2011 Springer Science+Business Media, Inc.
GP UkrNIIspetsstal’, Zarporozh’e, Ukraine.