EFFECT OF CHROMIUM AND ZIRCONIUM OXIDES
ON PROPERTIES OF BOBROVSK DEPOSIT QUARTZITE RAMMING MIXES
I. D. Kashcheev
and K. G. Zemlyanoi
Translated from Novye Ogneupory, No. 4, pp. 47 – 51, April, 2013.
Original article submitted January 28, 2013.
Processing research is carried out on Bobrovsk deposit quartzites. The effect of chromium and zirconium ox
ides, aluminochromium catalyst waste, and baddeleyite-corundum object scrap, on sintering, structure forma
tion, and properties of ramming mixes is studied. Laboratory tests are performed for slag resistance.
Keywords: quartzite, ramming mix, induction furnace lining, refractories, sintering, slag resistance.
Previous research has established that the mineral com-
position of Bobrovsk deposit quartzite is almost pure entirely
crystalline cemented quartzites of two types, i.e., light and
dark [1, 2]. In a practical respect both varieties are equivalent
and contain 98.82 and 98.06 wt.% SiO
size and substance composition of ramming mixes for lining
ferrous and nonferrous metallurgy induction furnaces have
been developed on the basis of Bobrovsk deposit quartzite.
A feature of induction furnaces is the small lining thick-
ness. However, the smaller the “crucible” wall thickness, the
shorter its service life, and there is also a reduction in furnace
operating reliability. Therefore improvement in chemical and
corrosion resistance of an inductor lining is an important
task. Production studies were carried out for the possibility
of improving lining corrosion resistance for a ramming in
duction mix based on Bobrovsk deposit quartzite.
In preparing an induction mix the most widespread
sintering addition is boron oxide (boric acid). A study of the
effect of B
on mix properties of Bobrovsk quartzite has
shown that addition in an amount of 1.5 – 3.0 wt.% is ade
quate for forming a dense and strong structure of a ceramic
“crucible”. It is well known  that a melt based on boron
oxide does not facilitate quartzite degeneration from one
polymorphic modification to another, but it effectively
sinters quartzite materials. Proceeding from theoretical as
sumptions it is considered possible to improve corrosion re
sistance of refractory materials with respect to slag, or any
other corrosive factor :
– by increasing chemical (thermodynamic) material
– by increasing thermal shock resistance (resistance to
drops in temperature);
– by reducing reaction surface between material and
melt (reducing pore volume and size);
– by changing the boundary wetting angle between ma-
terial and melt.
With respect to quartzite mixes and ferrous metallurgy
molten slags the most effective industrial method of improv
ing corrosion resistance is a change in thermal shock resis
tance and material wettability with slags. This is achieved by
introducing into a charge composition subordinate amounts
of substances not reducing material refractoriness and
strength, but improving its other properties.
Of materials known currently, not wetted by melts based
on iron, the most abundant, and consequently cheap and
accessible, are materials based chromium and zirconium
With respect of value of Gibbs energy Cr
are thermodynamically stable , and the oxide heat of for
mation is 1141.32 and 1101.30 kJ/mole respectively. This is
much greater than similar values for FeO and MnO (265.02
and 385.35 kJ/mole respectively), i.e., the main components
of steel oxidation at high temperature. Trivalent iron and
manganese oxides also have lower values of heat of forma
tion (822.71 and 958.36 kJ/mole respectively), than Cr
Chromium does not form chemical compounds or solid
solutions with SiO
. In the binary system Cr
Refractories and Industrial Ceramics Vol. 54, No. 2, July, 2013
1083-4877/13/05402-0106 © 2013 Springer Science+Business Media New York
FGAOU VPO Ural Federal University, Ekaterinburg, Russia.