STUDY OF THE INTERACTION OF MOLTEN ALUMINUM
WITH THE CONTACT SURFACE OF A QUARTZ REFRACTORY
R. A. Apakashev
and S. Ya. Davydov
Translated from Novye Ogneupory, No. 4, pp. 46 – 48, April, 2015.
Original article submitted November 11, 2014.
Results are presented from studies of the kinetics of the reaction in which silicon is reduced from silica by
molten aluminum. The micro- and nano-structure of molten aluminum in contact with the surface of a quartz
refractory were also investigated. It was established that at 985 K the contact reaction between the compo
nents of the heterogeneous system Al-SiO
takes place at an average rate of 5.7 ´ 10
·sec). It is
shown that the aluminum matrix structure which crystallizes in this system is characterized by the presence of
micro- and nano-particles of silicon.
Keywords: molten aluminum, quartz refractory, high-temperature reaction, rate of heterogeneous reaction,
micro-particles, nano-particles, alumomatrix composite.
The quartz refractories that are used in the aluminum in-
dustry are characterized by high heat resistance, low thermal
expansion, and low thermal conductivity. Fused quartz
refractories are obtained from a melt of natural or synthetic
silica having an SiO
content greater than 99%. The casting
method that is used makes it possible to obtain silica-bearing
products of complex shape. Thus, these refractories have a
wide range of uses — including applications in which they
come into direct contact with molten metal.
Thermodynamic analysis of the reactions in the Al-SiO
system shows that silicon can be reduced from its dioxide by
molten aluminum . Manufacturers make use of this fact
when they produce aluminum-silicon alloys by taking silicon
that has been reduced from silica and dissolving it in alumi
num [2, 3]. The scientific literature contains almost no infor
mation on the kinetic parameters of high-temperature reac
tions in the Al–SiO
system. The existence of such informa
tion would allow evaluation of the rate at which the contact
surface of a quartz refractory dissolves in molten aluminum.
That would in turn make it possible to determine the proba
ble source and quantities of impurity elements which might
enter the metallic melt and to predict the service life of the
This article reports results from studies of the rate of the
reaction in which silicon is reduced from silicon dioxide by
molten aluminum. It also presents results from electron mi-
croscope study of the structure of aluminum that is in contact
with the surface of a quartz refractory in the molten state.
As the components of the model Al–SiO
used primary aluminum of grade 40 (the counterpart of for-
eign-made aluminum ENAW-1100) and refractory tubes
composed of fused optical-grade quartz. A special unit was
designed  to bring about high-temperature contact be
tween the components of the Al–SiO
The unit (Fig. 1) includes a heating furnace 1 with a
working zone of a prescribed capacity and volume and a cru
cible 2 for the alumo-matrix melt 3. A slide gate 5 and a con
Refractories and Industrial Ceramics Vol. 56, No. 2, July, 2015
1083-4877/15/05602-0194 © 2015 Springer Science+Business Media New York
Ural State Mining University, Ekaterinburg, Russia.
Fig. 1. Unit for realizing high-temperature contact between the
components of the Al–SiO