EFFECT OF FELDSPAR CONCENTRATE
ON PROCESSES THAT OCCUR DURING FIRING
OF ACID-RESISTANT MATERIALS BASED ON NONFERROUS
METALLURGY CONCENTRATION WASTE MATERIALS AND PYROPHYLLITE
E. S. Abdrakhimova
Translated from Novye Ogneupory, No. 9, pp. 16 – 20, September 2008.
Original article submitted January 30, 2008.
Studies demonstrate that with a firing temperature of 1150ºC feldspar grains in acid-resistant materials change
very weakly, and they are mainly only vitrified along borders. An increase in firing temperature to 1200°C
promotes an increase in glass content. With a firing temperature of 1250°C feldspar grains are entirely re
placed by glass, penetrated by acicular mullite crystals.
The considerable demand from the chemical industry,
nonferrous metallurgy and other branches for acid-resistant
materials points output of large objects in the direction of the
most accessible and cheap raw material. Recovery and pro-
cessing of nonferrous metals is connected with forming a
considerable amount of various industrial waste materials
whose accumulation leads to worsening of the ecological sit-
uation in regions. One aspect of resolving this important
problem is the use of waste products in preparing ceramic
Of special interest and rarely encountered in publications
is use of acid-resistant waste materials produced by nonfer
rous metallurgy. These raw materials are used mainly as con
creting additions in ceramic charges. Use of waste products
from nonferrous metallurgy and power engineering is an ef
fective method for saving natural materials, and simulta
neously there is use of ancillary products and a contribution
is made to environmental protection.
It is well known that with a firing temperature for ce
ramic objects above 1200°C in the majority of cases feldspar
grains are transformed into aggregates of glass and acicular
mullite crystals [1, 2]. Normally this mullite is designated by
the index II in contrast from mullite I, synthesized as a result
of argillaceous substance and secondary mullite .
In publications [2 – 8] the fundamental possibility is
demonstrated of using the argillaceous part of zircon-ilmen
ite ore gravitation tailings (ZIG), pyrophyllite and feldspar
concentrate (FSC) in the production of acid-resistant materi-
als, The chemical composition of the test components is
given in Table 1.
ZIG is obtained after disintegration and screening of ore
in the form of a suspension with a moisture content of
37 – 45%, and in essence it is a refractory clay, but it has a
complex mineral composition, including in contrast to tradi-
tional refractory clays, more than ten minerals . The re-
sults of element-by-element spectral analysis, performed in a
spectrograph, showed the presence of titanium and zirco
nium (Fig. 1).
The mineral composition of ZIG includes, wt.%:
kaolinite + illite 43 – 48, hydromica + montmorillonite 8 – 12,
quartz 13 – 16, feldspar 18 – 20, calcite 2, zircon 2, ilmenite
3, iron oxides 3, organic admixtures 0.80 – 0.98. The refrac
toriness of ZIG is 152 – 1550°C, and in sintering capacity it
relates to a strongly sintering raw material with a sintering
range of 120 – 150°C.
The degree of ordering of the structure (crystallinity) of
kaolinite is expressed qualitatively, i.e. the kaolin
crystallinity index , that is the ratio of the sum of the
heights of two peaks of diffraction patterns for the test
Refractories and Industrial Ceramics Vol. 49, No. 5, 2008
1083-4877/08/4905-0336 © 2008 Springer Science+Business Media, Inc.
S. P. Korolev Samara State Aerospace University, Samara, Russia.
TABLE 1. Chemical Composition of Raw Material Components
Content, wt. %
CaO MgO R
ZIG 58.70 23.39 6.55 1.8 1.22 1.62 7.1
Pyrophillite 52.85 34.88 0.4 0.22 0.1 0.09 7.88
FSC 74.22 14.48 0.32 0.37 0.31 10.18 0.32