TESTING A NEW COMPOSITION OF PERICLASE SPINEL OBJECTS
T. V. Bayandina,
1
I. D. Kasheev,
2
A. I. Usherov,
3
and V. I. Shishkin
3
Translated from Novye Ogneupory, No. 8, pp. 16 – 17, August 2008.
Original article submitted March 10, 2008.
În the basis of periclase powder (70%) and aluminomagnesia spinel (30%), synthesized from secondary
aluminum production waste and caustic magnesite, test objects are produced of periclase spinel composition
satisfying the requirements of GOST 1579-006-00190495–98. The articles are successfully tested in the
working layer for lining tunnel furnace cars of OAO Kombinat Magnezit.
With the aim of utilizing dust waste materials from
secondary aluminum production (WSAP) for producing
periclase spinel refractories technology has been developed
for preparing aluminomagnesia briquettes containing
sintered aluminomagnesia spinel [1 – 3]. Periclase spinel
objects based on sintered aluminomagnesia briquettes have
been manufactured using sintered periclase fractions 3 – 0.5,
1 – 0, and < 0.063 mm (finely ground). The chemical
composition of the periclase powders is presented in Table 1.
Aluminomagnesia spinel was prepared by sintering from
WSAP dust and caustic magnesite, taken in the ratio 1:1 and
formed into briquettes with raw material having an apparent
density r
app
of the of 2.15 g/cm
3
, and an ultimate strength in
compression s
co
of 24.4 MPa. Briquettes were fired at
1750°C. The characteristics of fired briquettes are, wt. %:
SiO
2
5.20, Al
2
O
3
34.2, MgO 52.5, Fe
2
O
3
2.36, CaO 3.60,
Na
2
O 0.79, K
2
O 0.21, Dm
prc
0.25; r
app
= 2.74 g/cm
3
,
s
co
= 48.2 MPa. It was established by petrographic studies
that the texture of the briquettes obtained is porous. The pore
size is 4 mm. The mineral composition of sintered alumino
-
magnesia briquettes is, vol.%: spinel 60 – 62, periclase
33 – 35, silicates (forsterite, monticellite) 4 – 6, the rest
(sodium-potassium silicate, pyroxene, melinite, sodium
glass) 1. the predominant grain size of spinels is 22 – 25 mm,
and the maximum is 50 mm.
In developing technology for preparing periclase spinel
objects based on synthesized spinel it was directed towards
the properties of periclase spinel produced by OAO
Kombinat Magnezit [4]. The charge consisted of 15 – 20%
periclase powder fraction 3 – 0.5 mm, 20 – 25% periclase
powder fraction 1 – 0 mm, 25 – 30% aluminomagnesia
spinel powder fraction 0.5 – 0 mm, 25 – 30% finely ground
sintered periclase fraction < 0.064 mm. Objects of the
composition 30% spinel and 70% sintered periclase were
compacted at a pressure of 150 MPa in a hydraulic press and
fired at 1680°C in a tunnel furnace by the firing regime for
periclase-chromite refractories. The chemical composition of
the test periclase spinel objects was, wt.%: MgO 86.5, Al
2
O
3
6.83, SiO
2
2.52, CaO 2.15, Fe
2
O
3
1.86, Dm
prc
0.32. The
properties of the test periclase spinel objects were: open
porosity 14.6%, apparent density 3.01 g/cm
3
, ultimate
strength in compression 77.6 MPa, temperature for the start
of deformation under a load of 0.2 MPa 1580 – 1590°C, heat
resistance (1300°C – water) 6 – 7 thermal cycles, volumetric
shrinkage 0.7%. it follows from the data provided that the
test periclase spinel objects in physicomechanical properties
relate to the specifications for this class of objects.
It was established by petrographic studies that the
microstructure of an object is composed of granular filler and
finely ground matrix. The latter consists of uniformly distri
-
buted periclase particles throughout the volume of round and
Refractories and Industrial Ceramics Vol. 49, No. 4, 2008
255
1083-4877/08/4904-0255 © 2008 Springer Science+Business Media, Inc.
1
YuUrGU, Chelyabinsk, Russia.
2
GOUVPO YTTU–UPI, Ekaterinburg, Russia.
3
MGTU, Magnitogorsk, Russia.
TABLE 1. Chemical Composition of Periclase Powders
Sintered
periclase
fraction, mm
Weight fraction, %
SiO
2
Al
2
O
3
Fe
2
O
3
CaO MgO
Dm
prc
3 – 0.5 2.48 0.99 1.49 2.11 92.46 0.26
1 – 0 2.28 1.11 1.33 3.55 91.0 0.52
< 0.063
*
1
2.38 1.01 1.30 2.83 92.0 0.48
*
1
Finely ground component of periclase powder was prepared by
grinding sintered periclase fraction 0.5 – 0 mm that contained not
more than 3% CaO in a pipe grinder.
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