SCIENTIFIC RESEARCH AND DEVELOPMENT
GENERAL FEATURES OF MINERAL SUBSTANCE
V. A. Perepelitsyn
Translated from Novye Ogneupory, No. 3, pp. 149 – 152, March, 2012.
Original article submitted February 13, 2012.
Functional areas (stages): low-, medium-, and high-temperature, are established in accordance with cyclic
changes of composition, structure, and physicochemical properties of minerals (inorganic compounds) over a
wide heat treatment temperature range. In the low-temperature region (<0.3T
) pyrogenetic processes are of
governing importance causing dissociation of thermally active compounds and formation of pseudomorphic
minerals (phases) and nanostructures with high specific surface, porosity, and physicochemical activity. At
moderate temperatures (normally 0.3 – 0.8T
) a ceramic structure is formed, providing sintered products with
the maximum level of physicochemical properties. The high-temperature region (>0.8T
) has thermal aging,
discriminatory pyroselection of components, and thermal breakdown of ceramic material structure.
Keywords: high-temperature transformation, thermally active and thermally inert mineral substance,
pyrogenesis, pyroselection, material thermal aging.
The scientific basis of all high-temperature technology
(metallurgy, petrurgy, production of refractories, ceramics,
abrasives, glass, cements, and other materials) is information
about the behavior of mineral raw material and inorganic
substances on heating in various media. Temperature is the
main and most effective intense thermodynamic parameter,
giving rise to different phase and structural transformations
for any substance even in the absence of mechanical action.
It is well known that an insignificant increase in temperature
sharply increases the rate of the majority of physiochemical
processes. For example, with a temperature increase by 10°C
the rate of chemical reactions increases by a factor of two to
With respect to the nature and intensity of high-tempera
ture transformations all minerals and inorganic compounds
may be conditionally separated into two groups: thermally
active and thermally inert . It has been established that
among natural minerals (~3500 forms) and 40,000 synthetic
inorganic compounds more than 90% of mineral substances
are thermally active. Thermally active minerals and inor
ganic compounds are distinguished from thermally inert ma
terials by presence on a thermogram of some thermal effects
(for thermally inert materials the single thermal effect is
caused by melting) .
A natural and technogenic thermally active substance,
within the composition of material for producing ceramic
materials, on heating exhibits a property of multistage
change in composition and structure . Within functional
areas (stages); low-, medium-, and high-temperature, are es
tablished in accordance with cyclic changes in composition,
structure, and physicochemical properties of materials (inor
ganic compounds) (Figs. 1 and 2).
In the low-temperature region (<0.3T
) pyrogenetic pro
cesses are of governing importance causing dissociation of
thermally active compounds and formation of pseudo
morphic minerals (phases) and nanosize structures with the
maximum specific surface, porosity, and physicochemical
activity, for example caustic magnesite (nanopericlase, meta
kaolointe, metaserpentine, metaltalc, etc. In view of imper
fection of texture, structure, and clear non-equilibrium phase
composition of newly formed calcined material, it has an ex
cess of free energy and is in an activated state, as a rule, with
minimum mechanical strength. As a result of dissociation
(dehydration, decarbonization, desulfurization, etc.) the
number of components and phases in a mixture is regularly
reduced. As a result of removal of crystallization, zeolite,
Refractories and Industrial Ceramics Vol. 53, No. 2, July, 2012
1083-4877/12/05302-0104 © 2012 Springer Science+Business Media, Inc.
OAO Eastern Institute of Refractories, Ekaterinburg, Russia.