EFFECT OF MOISTURE ON MAGNESIA COMPOSITION
REFRACTORY STRENGTH PROPERTIES AND METHODS
INCREASING REFRACTORY MOISTURE RESISTANCE
A. V. Gulyaeva
Translated from Novye Ogneupory, No. 2, pp. 45 – 47, February 2014.
Original article submitted December 18, 2012.
The effect of moisture and environment on magnesia composition refractory strength properties is studied. A
method is proposed for increasing refractory moisture resistance by using impregnation with phosphate bind-
ers. According to results of the work alumochromium phosphate binder (ACPB) is most effective. Industrial
testing of a lining impregnated with this binder for the tuyere belt of a Kirovgrad Copper Smelting Plant hori-
zontal converter showed an increase in service life by 12 – 15%. The expediency of using impregnated
refractories in the most worn parts of heating unit lining is established, such as a converter tuyere zone, slag
belt of ore-smelting furnaces, and electric furnace flex assemblies.
Keywords: phosphate binders, thermal shock resistance, hydration, specific load, magnesia refractory.
It is well known that magnesia materials are inclined to-
wards hydration by a reaction
O + Mg(OH)
During operation of a lining based on magnesia composi-
tion on heating Mg(OH)
to 900°C it is transformed into
MgO dust-like fraction, which leads to a reduction in lining
strength. Long-term provision of refractories, for example in
the far north region, facilitates access of moisture from the
air into finished objects, contact of magnesia objects with
water with accidental escape from cofferdams, and other
cooling installations, and this worsens refractory quality
compared with the original indices. However, data for the
change in refractory strength as a result of their interaction
with water is clearly inadequate within published sources.
We have analyzed the changes of ultimate strength in
of refractories in relation to their storage du-
ration before installation in a metallurgical unit. This may be
retention in plant stores, i.e., refractory and metallurgical
combine manufacturers. Results of studies show that with an
increase in magnesia object contact time with moisture from
the air its mechanical strength decreases (Fig. 1) .
In order to determine the effect of moisture of refractory
strength properties original magnesia specimens (PKhS)
with a size of 36 ´ 36 ´ 50 mm fired at 1300°C and speci-
mens of the same dimensions impregnated with alumino-
chromium phosphate binder (ACPB) were used. For impreg-
nation fired specimens were held for 0.5 h in binder and then
calcined at 900°C. Prepared specimens were placed in a ves-
sel with water for 1, 15 and 30 days. After holding in water
they were extracted, and in order to remove mechanically
bonded water they were dried at 150 – 200°C for 0.5 h, after
which specimens were weighed. An estimate was made of
the amount of Mg(OH)
formed from the difference between
final and initial specimen weight. Experimental data pro-
vided in Tables 1 and 2 show that the amount of Mg(OH)
Refractories and Industrial Ceramics Vol. 55, No. 1, May, 2014
1083-4877/14/05501-0067 © 2014 Springer Science+Business Media New York
FGOAU VPO Ural Federal University, Ekaterinburg, Russia;
Fig. 1. Dependence of ultimate strength in compression s
ration t of refractory contact with moist air.