REFRACTORIES IN HEATING UNITS
HEATING FURNACE MONOLITHIC REFRACTORY LINING
V. A. Zamyatin
and I. V. Egorov
Translated from Novye Ogneupory, No. 3, pp. 80 – 83, March 2008.
Original article submitted October 30, 2007.
Contemporary solutions are presented for completion of a monolithic refractory lining for a heating furnace
using products produced by OOO Keralit.
Today the life of a heating furnace lining made of indi
vidual components for a flat suspended roof is 1 – 4 years,
for the side wall it is 1 – 3 years, and for a travelling hearth it
is 1 – 2 years depending on furnace operating conditions and
the grade of components used taking account of a period of
6 – 12 months between maintenance. The actual life the insu-
lation of skid pipes and travelling beams made of kaolin fiber
is not more than half a year. With time the fiber becomes
brittle and the insulation breaks down.
The main reasons for the short life of these linings is
breakdown of refractory components during periodic rapid
heating and cooling; insufficient material structural strength.
Use of fiber materials combined with individual refractories
for lining the walls appears to be inefficient. Use of expen
sive heat-resistant castings in order to increase the structural
strength of a travelling hearth also does not provide an ap
propriate investment in the results: with time the metal oxi
dizes, deforms and the lining fails.
Overseas and domestic experience of the construction of
furnaces in recent years showed that use of unmolded
refractories and heat insulating materials makes it possible to
obtain higher indices for life: 5 – 8 years for a flat suspended
roof, 7 – 10 years for the side walls and 3 – 5 years for a trav
elling hearth depending on furnace operating conditions and
grades of materials used. Moreover, a monolithic refractory
lining makes it possible to reduce the heat consumption and
to improve operating conditions for the servicing personnel.
This approach towards lining is based on use of contempo
rary unmolded refractories and effective heat insulating ma
terials, structural changes and innovations in making a
monolithic furnace lining excluding the breakdown of refrac
tory materials. Favorable operating results for heating fur
naces lined with refractory materials and components from
the company Keralit have been obtained in the section rolling
workshop of RUP BMZ, the sheet rolling workshops of
OAO MMK, and workshop No. 390 of FGUP PO Ural-
The use of unmolded refractory materials requires com-
prehensive consideration of the main features of design and
construction of a heating furnace. The main structural solu-
tions are presented below for a monolithic lining of indivi-
dual elements and assemblies of a heating furnace made of
advanced unmolded refractories produced by OOO Keralit
that make it possible to increase lining life and improve the
technical and economic indices of furnace operation.
FLAT SUSPENDED ROOF
Depending on the method of laying the working layer of
a flat suspended roof it is possible to prepare it by vibration
forming using CERALIT CAST concretes, by ramming
using CERALIT PLAST or torcreting using refractory mix
CERALIT GUN. With vibration forming and torcreting the
working layer of a monolithic lining of a flat suspended roof
with a thickness of 150 – 200 mm laying is carried out with
individual panels with a size of 1.0 – 1.5 m. Suspension of
panels is performed with ribbed ceramic stays perpendicular
to the metal structure of the roof by steel supports. Ceramic
stays are fastened through 250 – 300 mm in rows. Over the
perimeter there are stepped grooves that pierce the lining of
ceramic fiber. Insignificant shrinkage of panels during firing
is compensated by thermal expansion of the mix during heat
ing and thereby it excludes movement of stays. In preparing
the working layer of a monolithic lining of the roof by ram
Refractories and Industrial Ceramics Vol. 49, No. 2, 2008
1083-4877/08/4902-0075 © 2008 Springer Science+Business Media, Inc.
OOO Krealit, Russia.