FEATURES OF CHROMITE ORES FROM DIFFERENT DEPOSITS
AND THEIR EFFECT ON THE MICROSTRUCTURE AND PROPERTIES
OF PERICLASE-CHROMITE REFRACTORIES
I. G. Maryasev,
L. M. Mikhailovskaya,
A. A. Platonov,
O. A. Maryaseva,
and L. D. Bocharov
Translated from Novye Ogneupory, No. 2, pp. 9 – 25, February 2008.
Original article submitted May 22, 2007.
With the aim of selecting possibilities for use in industry of chromite ores from different deposits in order to
produce periclase-chromite refractories these ores are studied by optical and electron microscopy, and also
chemical and differential thermal analysis: Indian, Iranian, South African and Turkish. High temperature
changes that occur within them are described. Microstructural features for periclase-chromite refractories
based on these chromite ores and the interconnection of indices are revealed that make it possible to
recommend an ore for a specific application.
As is well known, chromite ore is a promising high-
temperature material for preparing refractory materials.
Dense, loose and powder ores are valuable as raw material
for the production of periclase refractories since during
production of some refractories a coarse-grained fraction (for
example 3 – 0.5 mm) is used, and in the production of others
a finely-ground fraction (for example £ 0.06 mm) is used.
Use of chromite ores from different deposits for pro
ducing periclase-chromite (PC) refractories containing from
5 to 35% Cr
 is only suitable from an economic pint
of view (suitable material cheaper than technogenic,
undesirable to use more expensive raw material for mass
production or to use cheaper material losing quality), but also
from the point of view of forming some refractory structures.
Microstructural features of chromite ore, chemical compo
sition, the content of impurity components and their nature
determine possible application in industry for any ore.
In refractory production it is most desirable to use chromite
ores containing not less than 35% Cr
, not more than 6%
, and not more than 1.5% CaO . The amount of basic
impurity, i.e. serpentine, may be at the level of not more than
15%, a greater amount of it reduces refractoriness and
deformation temperature under load. The content of iron oxides
in ores should also not be more than 16%. In PC-objects for
more critical purposes it is recommended to use ores of
increased quality, and in fact with a high Cr
less than 45%) and lower SiO
content (not more than
4 – 6%). For example, in order to produce vacuum degassed
steel chromite ores should be used with the minimum silicon
and calcium impurity content (less than 1%).
In view of the importance of providing the refractory
industry with chromite ores a study was made in this work of
four types of chromite ores from different deposits: Indian,
Iranian, South African and Turkish. Raw chromite ores of
different fractions were studied: Indian fraction 2 – 0 mm;
Iranian fraction 300 – 0; 2 – 0 and 0.5 – 0; South African
chromite concentrate DR-89, 2 – 0.5 mm, CM AFS, 0.5 – 0 mm ;
Turkish 3 – 0.5 mm. These chromite ores were also studied
after high-temperature firing. Then in order to estimate the
effect of these chromite ores on the structure and properties
of objects test periclase-chromite refractories based on them
Refractories and Industrial Ceramics Vol. 49, No. 1, 2008
1083-4877/08/4901-0017 © 2008 Springer Science+Business Media, Inc.
OOO Gruppa Magnezit, Russia.