POSSIBILITIES OF A THERMOMECHANICAL METHOD
FOR ENRICHING MAGNESIA-BEARING RAW MATERIALS
TO OBTAIN QUALITY MAGNESIA
A. N. Smirnov,
M. Yu. Turchin,
and R. N. Abdrakhmanov
Translated from Novye Ogneupory,No.4,pp.7–9,April, 2016.
Original article submitted January 21, 2016.
A thermomechanical method is examined for its potential use in concentrating magnesia-bearing raw materi
als from the Satka deposit by removing the impure components. It is shown that roasting magnesite within the
range 680 – 750°C and its subsequent break-up (abrasion) under certain mechanical loads can increase MgO
content in the <0.5 mm fraction of the roasted product nearly 10%. It is established that dust entrainment is
minimal and does not exceed 1.5% when the magnesite is roasted in a fixed bed. This result can be obtained
with a tenfold change in the thickness of the bed (from 20 to 200 mm).
Keywords: Satka magnesite, magnesia, thermomechanical concentration, dust entrainment, roasting time,
granulometric composition, refractory products.
The increasingly demanding requirements on the quality
of steel are making it necessary for metallurgists to introduce
new steelmaking methods, which usually entails greater
loading of the equipment that is used. The increased loading
is in turn tightening the requirements on the refractory prod
ucts employed in the equipment. The refractories should
have good durability and ensure that the equipment has a
long, repair-free campaign. In order for a manufacturer to
meet these requirements and remain competitive, it needs to
continually strive to improve the quality of its products.
It is known that the lower the content of impurities in re
fractory products — particularly CaO and SiO
— the better
the processing properties of the refractories. Despite this, it
has also been established  that the overall quality and, in
particular, the durability of refractories made of fused
periclase becomes nearly independent of the total and pro
portional impurity content when these refractories consist of
more than 97.5% MgO. However, even if there is a “thresh
old” value for the MgO content of fused periclase (>97.5%
) that makes the content of impurities almost insignificant,
the quality of roasted magnesite used in making refractories
increases with a decrease in its content of undesirable com
ponents (and, accordingly, an increase in its MgO content).
One method of increasing the amount of MgO in roasted
magnesite is thermomechanical concentration . Here, we
present the main results that have been obtained by using
thermomechanical concentration to remove impurity compo
nents from Satka magnetite.
OBJECT OF STUDY
AND EXPERIMENTAL METHOD
The magnesite raw material that was studied has a non
uniform phase composition. It consists mainly of magnesite
and contains dolomite, calcite, quartzite and other inclusions
as impurities . There are only small differences in the den
sity and hardness of these main initial components of crude
magnesite but substantial differences in their dissociation
(decarbonization) temperatures. Thermographic studies of
crude magnesite have shown that the decomposition of the
magnesium carbonate in magnesite takes place within the
range 630 – 680°C (Fig. 1). The impurity minerals — in par
Refractories and Industrial Ceramics Vol. 57, No. 2, July, 2016
1083-4877/16/05702-0121 © 2016 Springer Science+Business Media New York
Magnitogorsk State Technical University im. G. I. Nosova, Mag
”Magnezit” Group, Satka, Chelyabinsk region, Russia.