DIATOMIC HEAT INSULATION MATERIALS
WITH INCREASED APPLICATION TEMPERATURE
I. D. Kashcheev,
S. N. Sychev,
K. G. Zemlyanoi,
A. B. Klimovskii,
and S. A. Nesterova
Translated from Novye Ogneupory, No. 9, pp. 26 – 30, September 2009.
Original article submitted March 26, 2009.
Results are provided for a study of an increase in application temperature for diatomite objects. Different
molding methods and sample mix compositions are described for preparing objects based on diatomite with an
application temperature up to 1150°C.
Keywords: diatomite, application temperature, cristobalite, wollastonite, molding method.
The problem of effective use and saving of energy re
sources includes a list of critical technologies, and energy
saving technology, i.e. in priority areas of the development of
science and technology and engineering. As is well known
, there is dissipation into the environment through protec-
tive structures of up to 40% of heat with a temperatures of
gases discharged from 300 to 160°C, and therefore a reduc-
tion in this heat loss is an effective way of reducing the en-
ergy expended for manufacturing a production unit, and con-
sequently increasing its competitiveness in domestic and
Heat insulating materials in a refractory lining of a heat
ing unit fulfil an important task, i.e. they retain heat and
maintain the temperature at the required production level .
For the practical long-term use of any materials as a heat in
sulator two main characteristics are important . The tem
perature of the long-term application and the accumulation
capacity. The temperature of long-term application depends
on the form of the lightweight material and its production
technology. The most widespread aluminosilicate light
weight objects and unmolded mixes at the working tempera
ture and with prolonged operation, gradually sinter and there
is shrinkage. Here joints of the lining open, there is forma
tion of shrinkage cracks and other defects; the process is ac
companied by an additional increase in the thermal conduc
tivity of the lining and heat loss. Silica lightweight heat insu
lation materials, in contrast to aluminosilicate materials, dur
ing prolonged operation and at operating temperatures do not
sinter, and in some cases there is a small growth of them
(0.1 – 0.2%), providing lining tightness. The thermal con-
ductivity of the material is practically unchanged and it re-
mains constant over the whole operating period.
Silica raw material is encountered in natural and techni-
cal materials in amorphous and crystalline states: in
quartzites, quartz sands, tripolite, diatomite, opoka, and
marshallite . Of the amorphous materials for producing
lightweight objects for industrial purposes there is extensive
use of Inzensk deposit (Ul’yanov region) diatomite, as the
purest with respect to impurity content. The main technologi
cal positions for production and the properties of foam-diato
mite objects are given in publications [2, 3]. Diatomites
of the Inzensk deposit contain 74.80 – 88.15% SiO
3.34 – 9.75% (Al
), 2.37 – 5.26% (Fe
0.47 – 0.85% CaO, 0.61 – 1.71% MgO, 0.96% K
2.73 – 5.88%.
Diatomite is a light porous self-cementing sedimentary
rock, forming from residues of microscopic algae and
radiolarian skeletons. The amorphous nature of the silica dis
tinguishes it from normal silica. The greatest size of individ
ual skeletons (up to 1 mm) and the fractal nature of their
structure with a size of individual parts of about 100 nm,
forms a nano-porous material structure [3, 5]. In nature diat
omite of the Inzensk deposit contains amorphous silica
(82%, quartz (10%), and other impurities (8%). There are no
structural or phase transformations within this material on
heating up to 1000°C . Under industrial conditions the di
atomite objects are fired at 850 – 900°C , and the phase
composition of the fired objects corresponds to that provided
in publication .
Refractories and Industrial Ceramics Vol. 50, No. 5, 2009
1083-4877/09/5005-0354 © 2009 Springer Science+Business Media, Inc.
Proc. International Conference of Refractory Workers and Metal
lurgists (Moscow 23 – 24 April, 2009).
GOUVPO UGTU-UPI, Ekaterinburg, Russia.
OOO Scientific and Technological Center, Ul’yanovsk, Russia.
OOO PNK Diatomite-Invest, Ul’yanovsk, Russia.