COMBUSTION DURING FIRING HEAT INSULATION CERAMIC MATERIAL
BASED ON WASTE FUEL SHALE
V. Z. Abdrakhimov
and E. S. Abdrakhimova
Translated from Novye Ogneupory, No. 7, pp. 44 – 49, July, 2013.
Original article submitted November 27, 2011.
Combustion is studied for heat insulation material from production waste without using traditional materials.
It is shown that during heat treatment of heat insulation materials in the range 400 – 600°C the main part of
volatile substances is removed, in the range 1050 – 1100°C iron reduction accelerates significantly, and or
ganic material is almost entirely absent from ceramic material fired at 1100°C.
Keywords: heat insulation material, waste fuel shale, ash and slag mixture, intershale clay, combustion,
pyrocarbon, iron oxide, hydrocarbons.
The aim of this work is to study combustion during firing
of heat insulation materials made from technogenic raw ma-
terial (power generation waste) with an increased carbon
content without using traditional natural materials, since
combustion during firing of heat insulation material forms
the main physicomechanical properties of objects.
Previously [1 – 3] a fundamental possibility has been
demonstrated of using ash and slag mixtures from burning
fuel shales and intershale clay in the production of heat insu-
lation material. An ash and slag mixture from burning fuel
shales was used as a shortening agent, an intensifier, and a
partly burnt-off addition. During burning of fuel shales there
is formation of ash and slag. The ash and slag is finely dis
persed material consisting of the mineral part of burnt fuel
and is captured from thermal power plant flue gases. The
particle size of ash varies from 3 – 5 to 100 – 150 mm, the
ash density is 2.0 – 2.5 g/cm
, bulk density is
0.85 – 1.05 g/cm
, and specific surface is 1150 – 1280 cm
Slag is corrosive and melted ash particles with a size from
0.15 to 30 mm.
The process of forming an ash and slag mixture proceeds
by the following technology: shale from the Kashpirsk mine
is supplied to the Syrzansk thermal power station, loaded
into receiving bunkers, and fed by belts into hammer crush
ers for the first grinding stage. Pellets obtained (grain size up
to 15 mm) enter shaft mills in the second grinding stage.
With a stream of air fine powder is blown through a special
nozzle into the combustion chamber of steam water-tube
boilers. Heat treatment of shale commences in the combus-
tion chamber. In the gas conduits and in dust deposition de-
vices there is natural fractionation of ash. Coarse particles
settle in the combustion chamber (25%) medium size parti-
cles in the economizer (5%), multicylones (35%), and very
light particles in electric filters (30%) Some part of the ash is
carried away with gases into the atmosphere (5%). The aver-
age chemical composition of ash and slag mixture is pre-
sented in Table 1. An increased content in ash and slag mix-
ture of Fe
O makes it possible to intensify (to re
duce firing temperature) firing, and Dm
to reduce heat in
sulation object density.
Intershale clay was used as a binder for preparing heat
insulation material. It forms during recovery fuel shales in
shale processing plants (in shafts), and with respect to plas
ticity number it relates to highly plastic argillaceous raw ma
terial (plasticity number 27 – 32) with true density
2.55 – 2.62 g/cm
. The chemical composition of intershale
clay is presented in Table 1.
Questions are posed in this work for combustion kinetics
of carbon particles during heat insulation material firing of
optimum composition, wt.%: intershale clay 80, ash and slag
mixture 20 [1 – 3]. Physicomechanical properties of heat in
Refractories and Industrial Ceramics Vol. 54, No. 4, November, 2013
1083-4877/13/05404-0299 © 2013 Springer Science+Business Media New York
FGBOU VPO Samara Academy of State and Municipal Manage
ment, Samara, Russia.
TABLE 1. Component Chemical Composition, wt.%
CaO MgO R
Ash and slag mixture 55.30 14.56 6.4 1.51 0.5 4.78 16.5
Intershale clay 47.03 16.80 5.6 10.90 2.1 3.40 12.8