IMPROVEMENT OF SHAFT FURNACE CONSTRUCTION
FOR ROASTING LIMESTONE
A. F. Reshetnyak,
V. A. Konev,
A. N. Mamaev,
and N. I. Seryakov
Translated from Novye Ogneupory, No. 5, pp. 25 – 27, May 2008.
Original article submitted October 30, 2007.
Specialists of the Ural State Technical University together with OAO Lipetskstal’proekt have carried out
reconstruction of shaft furnaces for roasting limestone in OAO Nikolaevsk Alumina Plant. As a result of
changing heat exchange conditions in the furnace a special construction is developed for a gas distribution
core installed in the furnace firing zone, and other engineering solutions introduced make it possible to
stabilize limestone roasting in shaft furnaces.
One of the most important users and producers of lime is
the metallurgical industry. The quality of metallurgical lime
essentially governs the technical and economic indices of the
main processes in both ferrous and nonferrous metallurgy.
Different requirements are laid down for lime used in
metallurgy in relation to its purpose dictated by the pro-
cessing technology: the degree of roasting, the content of
active components, reaction capacity, fluxing capacity, etc.
Analysis of the results of studying dissociation kinetics for
limestone from different deposits indicates that some lime
properties may be obtained with correct choice and strict
observation of quite narrow temperature and time parameters
for roasting. Thus, the technical and economic and
qualitative indices of roasting limestone are mainly governed
by the engineering perfection of capacity to control the
In the metallurgical industry of Russia and CIS countries
there is extensive use of shaft furnaces for roasting lime
stone, operating on liquid or gaseous fuels; more than half of
the lime is produced in them. The number of these furnaces
is increasing due to a change-over from charge furnaces
operating on coke, to heating with natural or mixed gases.
It should be noted that the engineering level and corres
pondingly the technical and economic indices for operation
of these furnaces mainly relate to modern requirements.
Today under conditions of a constant increase of the
price of raw material, transport and energy, and under
conditions of an extremely stressed ecological situation in
industrially developed regions it is important to develop
efficient limestone roasting technology, the creation of new
and improvement of existing roasting units. This will make it
possible to provide high quality lime, saving and rational use
of fuel resources, a reduction in air basin contamination and
improvement of the ecological situation in the area of an
Existing shaft furnaces for roasting limestone traditio-
nally comprise a lined shaft with zone arranged for heating
limestone and cooling lime. Efficient operation of a shaft
furnace is governed to a considerable extent by conditions of
the combined occurrence of fuel burning, heat exchange and
carbonate dissociation. The development of rational heating
schemes is mainly connected with providing the required
material treatment regime with the minimum fuel consump
tion. Currently in these furnaces the main scheme for
organizing the process is counterflow. It is well known from
heat exchange theory that in a thermal respect with absence
of endothermic processes the counterflow scheme is the most
rational since it provides the minimum heat loss with exhaust
The aerodynamic regime has a decisive effect on
limestone firing in a shaft furnace. In charging the shaft the
volume of space at the furnace wall is always greater than in
the central part. In view of this the aerodynamic resistance of
a shaft filled with material is always higher in the central part
compared with the periphery. This effect, called the
“boundary effect”, leads to nonuniform distribution of the
gas flow rate, a drop in temperature to 400 – 500°C through
the shaft cross section, and consequently to excessive
consumption of fuel and a reduction in the quality of the lime
Analysis of the construction and operation of shaft
furnaces currently in operation for roasting limestone has
Refractories and Industrial Ceramics Vol. 49, No. 3, 2008
1083-4877/08/4903-0177 © 2008 Springer Science+Business Media, Inc.
ZAO Soyuzteplostroi – Lipeik, OAO Lipetskstal’proekt, Russia.