MICROSTRUCTURAL STUDY OF PERICLASE POWDERS
FOR PRODUCTION OF PERICLASE-CARBON COMPONENTS
L. T. Loginova,
V. G. Ovsyannikov,
L. V. Mironova,
and N. R. Khomenko
Translated from Novye Ogneupory, No. 11, pp. 35 – 37, November, 2003.
Results of a microstructure analysis of periclase powders (from China) of fractions 3–1mmarereported.
In the production of refractory materials for the lining of steel ladles, preference should be given to fused
The quality of periclase powders for production of mag
nesia refractories is evaluated in terms of four major parame
ters: (i) chemical composition, (ii) periclase crystal size,
(iii) grain porosity, and (iv) apparent grain density. The wear
resistance of magnesia refractories varies significantly with
these parameters. The quality of periclase powders improves
with increase in concentration of MgO, periclase crystal size,
and apparent grain density, and with decrease in grain poro-
In this paper we have studied the microstructure of peric-
lase powders of fractions 3–1mm(from China) purchased
from various suppliers for production of periclase-carbon re-
fractory components for steel ladles.
SINTERED PERICLASE POWDERS
AVAILABLE FROM DALMOND,
FERROMIN, AND MEIERTON
The powder grains were isometric periclase crystals se
parated by thin silicate interlayers of montmorillonite
CaO × MgO × SiO
and merwinite 3CaO × MgO × 2SiO
thickness 2 – 5 mm (Fig. 1). All the powders contain fine-
crystalline grains with periclase crystals 30 – 60 mm across
(Fig. 1a, c, e) and grains with larger periclase crystals up to
150 mm across (Fig. 1b, d, f ). By a rough estimate, the aver
age size of periclase crystals in the Dalmond powder is
somewhat larger than in the other powders. In all the pow
ders, most grains display numerous rounded, closed pores
5–50mm across that are located inside the crystals and at
intercrystalline boundaries. Fractured grains are also encoun
tered with different crack widths (see Fig. 1c–e).
Grains in the sintered powders display a high porosity.
The periclase crystals are isometric and vary in size. The
MgO crystals vary in size from 30 to 150 mm.
FUSED PERICLASE POWDERS AVAILABLE
FROM DALMOND, FERROMIN, AND MEIERTON
Microstructurally, most grains of the Dalmond powder
are large, fragmental periclase crystals up to 1500 mm across
(Fig. 2a ). Present in lesser amounts are grains composed of
compactly cemented polygonal and isometric large and small
periclase crystals 70 – 400 mm across. Silicates (merwinite,
b-2CaO × SiO
) appear as rounded aggregates at the peri
phery of periclase crystals or as thin interlayers separating
MgO crystals. Pores in the grains are closed, of size 10 – 50 mm
across, occasionally up to 200 mm.
Most Ferromin grains are composed of polygonal and
isometric periclase crystals 80 to 600 mm across (Fig. 2b ).
Less frequent are grains composed of prismatic and frag
mental crystals up to 1000 mm across. Silicates occur mostly
Meierton powder grains are composed of large polygonal
compactly cemented periclase crystals up to 800 mm across
and isometric crystals 70 – 300 mm across. Some 30% of
grains have a size of about 1 mm and display a fine crystal
line high-porosity structure with MgO microcrystals 20 –
40 mm across (Fig. 2c ). Possibly, these grains are composed
of sintered or partially fused periclase.
The fused powders look inhomogeneous. They are in
fact a mechanical mixture of various periclase materials of
different microstructure and with different degree of fusion.
The Dalmond powder shows a higher uniformity in compari
son to other powders. Predominant species in its composition
are grains of large periclase crystals up to 1500 mm across.
Refractories and Industrial Ceramics Vol. 44, No. 6, 2003
1083-4877/03/4406-0396$25.00 © 2003 Plenum Publishing Corporation
Magnitogorskii Iron-and-Steel Works Joint-Stock Co., Magnito