EFFECT OF PYROPHILLITE ON THE DRYING PROPERTIES
OF ACID-RESISTANT REFRACTORIES BASED ON THE ARGILLACEOUS PART
OF ZIRCON-ILMENITE ORE GRAVITATION TAILINGS
E. S. Abdrakhimova
Translated from Novye Ogneupory, No. 11 pp. 17 – 19, November 2009.
Original article submitted August 18, 2009.
It is established that an increase in pyrophyllite content in acid-resistant refractory specimens leads to a reduc
tion in molding and equilibrium moisture content, which is connected with a reduction in the weight fraction
of hygroscopic argillaceous component. There is an increase in moisture content and moisture conductivity at
the end of specimen shrinkage. Formation of surface cracks in specimens with an increase in the amount of
pyrophyllite is reduced, that is apparently due to a reduction in mix plasticity.
Keywords: pyrophyllite, acid-resistant refractory, drying properties, argillaceous part of acid-resistant refrac-
As is well known, the drying properties of a ceramic mix
are determined by a set of thermophysical and structural and
mechanical properties. Thus, the properties are: the degree of
shrinkage, i.e. relative shrinkage d; moisture conductivity a;
limiting tensile strain, proportional to the drop between the
specimen moisture content and its moisture content at the
surface at the instant of crack development (W
Important values for estimating the drying properties of a
mix are molding moisture content W
, equilibrium moisture
, and moisture content at the end of shrinkage W
Shrinkage phenomena, accompanied by the release of mois
ture from ceramic mixes, have a decisive effect on the choice
of the optimum drying regime for objects. This is connected
with the fact that shrinkage stresses occur in the period of
forming the pre-firing structure of the material.
In publications [2 – 5] a fundamental possibility of dem
onstrated of using the argillaceous component of zircon-il
menite ore gravitation tailings (ZIG) and pyrophyllite in the
production of acid-resistant refractories. The chemical com
position of the test components is presented in Table 1. Re
sults are provided in this article for determining the drying
properties of acid-resistant refractories prepared by plastic
molding of a mixture of ZIG and pyrophyllite.
The effect of pyrophyllite on the drying properties of
acid-resistant refractories has been studied in the composi-
tions provided in Table 2. The original components were
ground to a powder through a screen No. 1.25, carefully
mixed and moistened to W
of 25 – 20% (depending on the
Refractories and Industrial Ceramics Vol. 50, No. 6, 2009
1083-4877/09/5006-0409 © 2009 Springer Science+Business Media, Inc.
S. P. Korolev Samara State Aerospace University, Samara, Russia.
TABLE 1. Chemical Composition of Raw Material Components
CaO MgO R
ZIG 58.74 21.39 6.21 1.76 1.22 1.82 7.34
Pyrophyllite 52.85 34.88 0.40 0.22 0.10 0.09 7.88
TABLE 2. Composition of Ceramic Mixes for Producing Acid-Re
Component content, wt.%, in composition
ZIG 100 80 70 60 50
Pyrophyllite — 20 30 40 50