MAGNESITE ENRICHMENT BY A DRY METHOD
A. M. Urvantsev
and I. D. Kashcheev
Translated from Novye Ogneupory, No. 4, pp. 12 – 15, April, 2012.
Original article submitted January 16, 2012.
Results are provided for enrichment of low grade magnesite of the Satkinsk deposit (MgO 43.1%, CaO 4/07%,
50.6%) by electric separation. The concentrates 1 and 2 obtained contain 96.9 and 97.1% MgO,
1.32 and 1.36% CaO, and 0.16 and 0.19% SiO
respectively. With enrichment of calcined magnesite by elec
tric separation the concentrates 1 and 2 obtained contain 97.3 and 97.09% MgO respectively with a dry overall
yield equal to 38%. The starting periclase powder contains 95.5% MgO.
Keywords: magnesite, enrichment, periclase powder, electric separation.
In ferrous metallurgy (steel smelting production) inex-
pensive periclase-containing refractories are steadily being
replaced by high quality refractories, providing high service
indices. There are two main reasons for this, i.e., technical
and economic. The high cost of overseas periclase-contain-
ing materials makes a final refractory product more expen-
sive, and often limits its application. Therefore an important
area in the production of refractories is development of do-
mestic materials, expansion of their range, and rational utili
The proportion of enriched raw material in the form of
concentrates in production of refractories increases steadily.
Traditional methods for preparing refractory material con
centrates (magnesites, kyanites, graphites, etc.) normally in
clude gravitational enrichment, flotation, X-radiometric and
photometric separation, etc. However, in these methods there
is no complete provision of the required concentrate quality
for refractory production, or it is performed with increased
energy and ecological expenditure.
Use of high quality concentrates and synthetic compos
ites requires introduction of especially rapid production pro
cesses for refractory production, including briquetting and
high-temperature (1850 – 2200°C) firing of raw materials,
preparation of multicomponent mixtures based on 5 – 7 nar
row powder fractions, and use of devices for ultrafine disper
sion of materials and powerful press equipment.
Natural magnesites are impoverished with admixtures of
dolomites, calcites, quartz, and other mineral phases. Impu-
rity phases are removed by selective recovery followed by
manual sorting or enrichment of magnesite by flotation, or in
heavy suspensions. The last method is implemented on an in-
dustrial scale in OAO Kombinat Magnezit. With the flotation
method of enrichment during crushing to a size of less than
0.074 mm, when all of the mineral phases are exposed, the
content in concentrate of the main phase (magnesite) is
markedly increased, and the content of admixtures is re
duced. As a result of work carried out for enrichment of
magnesite by flotation optimum production regimes have
been established. It is recommended to grind magnesite to a
content of 60 – 70% particles less than 0.074 mm.
It has been established that during flotation of Satkinsk
deposit ore with a content of 2.97% CaO the overall yield of
magnesite concentrate corresponds to 69%, and the concen
trate contains 0.88% CaO and 0.13% SiO
. The reagents rec
ommended (carboxy methyl cellulose combined with sodium
hexametaphosphate in a soda medium) effectively suppress
calcite, dolomite, silicates, and quartz during selective flota
tion of magnesite with a carboxyl type collecting agent.
Flotation requires constant addition of not less than 20%
fresh water; in recycled water flotation is unsatisfactory and
separation of magnesite from dolomite is disrupted. The
main reason for instability of extraction indices is the imme
diate and non-optimum physiochemical condition of the flo
tation pulp. Impurities accumulated in the liquid phase (recy
cled water) having a negative effect during flotation are fatty
Refractories and Industrial Ceramics Vol. 53, No. 2, July, 2012
1083-4877/12/05302-0078 © 2012 Springer Science+Business Media, Inc.
OOO Russian Corona, Ekaterinburg, Russia.
FGAOUVPO Ural Federal University, Ekaterinburg, Russia.