PERICLASE CONCRETES BASED ON A SILICATE BINDER
A. A. Platonov
and I. G. Maryasev
Translated from Novye Ogneupory, No. 6, pp. 121 – 124, June 2011.
Original article submitted May 12, 2011.
OOO Gruppa Magnezit has developed a new generation of periclase cement-free concretes based on a
binder with a service temperature from 1500 to 1700°C depending on filler composition. The tech-
nology assimilated makes it possible to prepare refractories of complex shape for lining elements of CBCM
intermediate ladles and other units.
Keywords: refractories, periclase, cement-free concrete.
Refractory concretes are distinguished from normal
refractories by the fact that as a result of using special binder
materials at normal and somewhat elevated temperature
there is formation of strong monolithic structure, which does
not break down at high service temperature. As a result of the
evolutionary development of traditional concretes into
high-alumina cement (HAC) at the end of the 1970s low-ce-
ment concretes were created and somewhat later ultra-low
cement and cement-free refractory concretes were devel-
oped. The latter started their development after a sharp
change was revealed in refractory concrete properties under
the action of very fine additions of oxide materials with high
Control of concrete fluidity with a minimum water con-
tent is accomplished by addition to it of microdispersed sili-
con dioxide. This amorphous silicon oxide with a particle
size less than submicron, is an effective matrix component,
improving fluidity and reducing concrete porosity. For the
majority of concretes the high reactivity if silicon oxide pre-
vents a reduction in strength on heating in the temperature
range 700 – 900°C, when a hydraulic binder is broken down.
Concretes with a binder composition MgO–SiO
are used extensively in many countries, although normally
the mixture exhibits characteristics that prevent application
of these concretes with use of contemporary technology, for
example with application by a pump, and wet torcreting.
Apart from inadequate fluidity, the problem is the short inter-
vals of time during which the concrete is suitable for treat-
ment. A considerable microsilica content accelerates the set-
ting reaction and simultaneously improves fluidity. An im-
portant aspect in developing these concretes is use of suitable
additions of finely ground fractions, and a sufficient amount
of microdispersed SiO
in order to control fluidity and set-
ting with a low water content. Preparation of objects based
on concrete made from periclase and microsilica with a pre-
scribed structure and required properties is achieved by a ra-
tional ratio of their components. Rheological properties, i.e.,
concrete mix spreading, are controlled by introduction of
deflocculating additions. Choice of the optimum surfactant
has made it possible to prepare highly mobile mixes with
good laying and spreading capacity with a small addition of
water (15 – 16 vol.%, 5.5 – 6 wt.%), and also with a suitable
fitness time for casting. High mobility of concrete mix makes
it possible to manufacture objects of different and complex
Studies have shown that microdispersed SiO
, added to
periclase filler, enters into reaction with water, as a result of
which there is formation of magnesia-silica hydrate phases,
which promote concrete setting (Fig. 1a, b, Fig. 2), and also
strong bonds with high strength properties.
Thermogravimetric studies of the concretes obtained
have determined that on heating materials to a temperature
above 850°C forsterite starts to form within them. Comple-
tion of concrete structure formation ceases at 1450 – 1500°C.
Formation of forsterite on heating concrete is clearly re-
corded by x-ray phase analysis (Fig. 3).
A study of the microstructure of specimens of periclase
concrete, fired at 1500°C, showed that they are a brown
sintered mix, within which periclase filler grains are bonded
with the matrix consisting of finely dispersed periclase and
forsterite particles (see Fig. 1c, d, Fig. 4). The material struc
ture has low porosity with a predominance of closed pores of
Refractories and Industrial Ceramics Vol. 52, No. 3, September, 2011
1083-4877/11/05203-0223 © 2011 Springer Science+Business Media, Inc.
OOO Gruppa Magnezit, Satka, Chelyabinsk Region, Russia.
Yu. E. Pivinskii, Unmolded Refractories, Vol. 1 [in Russian], Tep
loenergetik, Moscow (2003).