Vol.:(0123456789) 1 3
Applied Physics A (2020) 126:198
https://doi.org/10.1007/s00339-020-3369-z
Effect of synthesis method on structural and physical properties
of MgO/MgAl
2
O
4
nanocomposite as a refractory ceramic
Hamidreza Shafiee
1
· Alireza Salehirad
1
· Abdolreza Samimi
2
Received: 25 November 2019 / Accepted: 17 January 2020 / Published online: 15 February 2020
© Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract
This work is a comparative study of MgO/MgAl
2
O
4
refractory nanocomposites synthesized by three different liquid phase
methods. Physical–chemical and microstructural characteristics of the refractories have been characterized in terms of bulk
density, apparent porosity, water adsorption capacity, crystalline phases, crystallite size, particle size distribution, morphol-
ogy and composition. The mechanical behavior of the synthesized samples was evaluated in terms of bend strength and
cold compressive strength. The thermal expansion coefficients of the MgO/MgAl
2
O
4
refractories were also measured from
room temperature to 1200 °C.
Keywords Magnesia/spinel · Nanocomposite · Refractory ceramic · Synthesis method · Physical properties
1 Introduction
Magnesia-based refractory ceramics have been extensively
used in the iron and steel industries, cement and lime rotary
kilns and or in non-ferrous metallurgical usages under dras-
tic statuses [1–4]. Because of its supreme chemical and
thermo-mechanical properties, magnesium aluminate spinel
(MgAl
2
O
4
) is a significant constituent of magnesia-based
refractory materials [5, 6].
Owing to the great discrepancy in thermal expansion
coefficient between magnesia and spinel, the thermal shock
resistance of magnesia can be amended by adding magne-
sium aluminate spinel, as the service life of magnesia–spinel
bricks in cement rotary kilns is two to three times longer in
comparison with conventional magnesia–chromite bricks
[7–10]. Another advantage of magnesia–spinel over mag-
nesia–chromite is that, contrary to the toxicity of chromium
in the conventional sample, magnesia–spinel is environmen-
tally compatible [11].
The effects of various factors such as particle size distri-
bution of spinel [12], mean particle size of spinel [13], spinel
content [5, 13, 14], different grades of magnesia [15], raw
material morphology [16] and different additives [17–21]
on the properties of magnesia–spinel refractory composites
were investigated.
In most cases, the solid state methods which have high
energy consumption were used to prepare magnesia–spinel
composite refractories [14, 20–24]. In the present work, to
study the influence of the synthetic method, magnesia–spinel
refractory nanocomposites were synthesized by three differ-
ent liquid phase methods and their structural and mechanical
properties were compered.
2 Experimental
2.1 Materials
The starting chemicals with laboratory-grade purity were
provided by Merck.
2.2 Synthesis of magnesium aluminate (MgAl
2
O
4
)
spinel nanoparticles
The synthesis of spinel was performed in accordance with a
previously reported approach [25]. To an aqueous solution
of Mg(NO
3
)
2
.6H
2
O and Al(NO
3
)
3
.9H
2
O (Mg:Al molar ratio
* Alireza Salehirad
a.r.salehirad@gmail.com; salehirad@irost.ir
1
Department of Chemical Technologies, Iranian Research
Organization for Science and Technology (IROST), Tehran,
Iran
2
Chemical Engineering Department, University of Sistan
and Baluchestan, Zahedan, Iran