DEVELOPMENT OF A PROCEDURE
FOR MODIFYING NANOMATERIALS OF MULLITE-CORUNDUM MIXES
IN EQUIPMENT WITH A HIGH-INTENSITY ROTATING
D. V. Kuznetsov,
M. A. Kostitsyn,
Yu. V. Konyukhov,
A. V. Mitrofanov,
D. V. Lysov,
A. G. Yudin,
D. S. Muratov,
and I. N. Burmistrov
Translated from Novye Ogneupory, No. 2, pp. 35 – 40, February, 2012.
Original article submitted September 16, 2011.
The possibility is demonstrated of a considerable improvement in mechanical properties of vibration-cast re
fractory objects by introducing nanosize fractions into thixotropic mullite-corundum mixes. It is established
that the efficiency of using nano-additions is governed by its introduction technology into refractory material.
The best method is mixing in vortex layer equipment with use of a high-intensity rotating magnetic field.
Keywords: refractory concretes, nanomaterials, ceramics, high-intensity action, electromagnetic field.
Currently use of nanomaterials is one of the most effec-
tive methods for increasing the operating properties of vari-
ous ceramic and composite materials [1, 2], and therefore
their use in refractory production for metallurgical purposes
is logical and promising. In this work in order to improve the
operating properties of refractory moldable objects made
from a thixotropic mullite-corundum mix, ceramic nano
powders are used with an average particle size of 20 nm
(0.02 mm). The physicochemical characteristics of refracto
ries laser diffraction, x-ray analysis, electron and optical mi
croscopy, low temperature nitrogen absorption, etc. Within
the scope of model experiments comparative analysis was
carried out for different procedures for introducing
nanomaterials into refractory mixes, i.e., mixing in dry form,
use of nanoparticle suspensions, treatment in vortex layer
Studies have shown that the optimum method for intro
ducing nanoparticles into refractory mixes, making it possi
ble to the greatest extent to use the advantages of the
nanosize condition, is treatment of material in vortex layer
equipment (VLE). In VLE under the action of a high power
rotating electromagnetic field ferromagnetic working bodies
and brought into intense vortex movement. As a result of this
within a workspace a number of effects are generated, arising
with impact of particles over each other, over a substance,
over the workspace walls, and in contact between ferromag-
netic working bodies. The overall effect of these factors cre-
ates a high level of activation for all of the components of
substances participating in the process, and provides uniform
distribution of charge components throughout a material vol-
ume. It is established that addition to unmolded refractory of
nanoparticles in an amount of 0.04% makes it possible to in
crease the ultimate strength in compression for corun
dum-mullite objects by 35 – 40%; there is an increase in ob
ject density up to 3%.
Analysis of technology for using nanomaterials in the re
fractory industry according to published sources indicates
that a significant part of the work is concentrated on improv
ing the operating properties of unmolded refractories [3 – 6].
This is mainly connected with the tendency observed
throughout the world of replacing brick refractories for heat
ing units by monolithic vibration-compacted and poured ma
terials. In particular, considerable attention is devoted to in
creasing the operating properties of corundum-containing
thixotropic low-cement mixes, which are used extensively in
preparing monolithic refractory linings and objects in the a
working zone with temperatures up to 1750°C [7 – 9]. Vari
ous authors note that micro-additions of nanomaterials (ox
Refractories and Industrial Ceramics Vol. 53, No. 1, May, 2012
1083-4877/12/05301-0054 © 2012 Springer Science+Business Media, Inc.
National Research technology Institute MISiS, Moscow, Russia.
OAO Severstal’, Cherepovets, Russia.