STUDY OF MEDIUM-CEMENT CONCRETE
BASED ON MIXED CHAMOTTE-PERICLASE CHROMITE FILLER
and R. Stonis
Translated from Novye Ogneupory, No. 8, pp. 42 – 46, August 2008.
Original article submitted April 8, 2008.
The possibility is demonstrated of using an addition of periclase-chromite filler (PCF) prepared from PCF
grade broken material articles in medium-cement concrete with chamotte filler. The effect of this addition on
cement hardening duration, strength and heat resistance is considered.
Periclase-chromite and chromite-periclase refractory ob-
jects contain ecologically hazardous hexavalent chromium
oxide, and therefore in the last ten years there have been
endeavours to replace them by chromium-free magnesia
refractories: periclase-lime, lime-periclase, periclase-spinel,
etc. . However periclase-chromite and chromite-periclase
refractories are still used quite extensively in metallurgy and
to a lesser degree in the cement industry.
Although waste refractory objects after operation are a
valuable raw material, considerable amounts of them are
thrown into tips. Unutilized chromium-containing waste cre-
ates a certain ecological threat of ground water contamina
tion. Recently reprocessing of these waste materials has re
ceived more attention, i.e. powders are produced, used in the
production of periclase-chromite and chromite-periclase ob
jects and mortars; fillers for coating steel-pouring chutes and
refractory concretes used in lining metallurgical furnaces.
A chemical binder is mainly used in manufacturing mag
nesia concretes. A combined binder (4 – 5% alumina cement
and 16% water glass) has been used in concrete as a mixed
filler, consisting of broken magnesia-spinel objects and co
rundum waste materials . Aluminomagnesia spinel is in
troduced into the composition of dry refractory mixes of
low-cement concretes based on corundum and mullite-co
rundum. Separate studies [3, 4] have been devoted to phase
formation between components in these concretes.
The possibility is studied in this work of using an addi
tion of filler prepared from broken periclase-chromite ob
jects in concrete based on chamotte filler with an alumina ce
ment. It is well known  that MgO in basic refractory ob
jects hydrates in a moist medium (brucite Mg(OH)
that in a system with alumina cement may lead to undesir
able consequences such as problems with rheology and con
crete laying, and also with hardening.
Of particular interest is a study of the heat resistance of
this concrete. It is well known that the heat resistance of
chamotte objects is 10 – 15 cycles (heating to 1300°C — wa-
ter cooling), and for periclase-chromite objects it is only
3 – 6 cycles . The heat resistance of the latter depends to a
considerable degree on the composition of components, the
width of circular pores around chromite grains, chromite
grain cracking, the degree of their bonding with a
finely-ground component, etc. . It has been established 
that after the first thermal shock there is a considerable re
duction in elasticity modulus of this material, and
microcracks form within the structure of an object. The au
thors of the present work have studied the effect of a mixed
chamotte periclase filler on hardening, physicomechanical
properties and heat resistance of medium-cement concretes.
The following materials were used for these studies:
microsilica grade 983U from the Norwegian firm Elkem
ASA Materials (SiO
98.6%); alumina cement Gorkal-40
produced in Poland (Al
³ 40%); chamotte filler, prepared
from chamotte brick grade ShA (Al
£ 40%) by crushing
and screening on sieves; fine chamotte, prepared by grinding
in a laboratory ball mill; deflocculant Castament FS 20, relat
ing to a group of polycarboxylate esters produced by BASF
(Germany), and anhydrous commercial grade sodium
Periclase-chromite filler (PCF) was prepared by crushing
objects grade PKhTs, whose density is 3000 kg/m
, and filler
grain size composition, %: fraction 5 – 10 mm — 17;
Refractories and Industrial Ceramics Vol. 49, No. 5, 2008
1083-4877/08/4905-0373 © 2008 Springer Science+Business Media, Inc.
Gediminas VTU Institute of Heat Insulation, Vilnuis, Latvia.