MLS-62 REFRACTORIES IN LINING LIME-REGENERATING
I. P. Malyshev,
V. D. Troyan,
N. A. Troshenkov,
V. N. Pribora,
A. V. Likhodievskii,
A. N. Pyrikov,
N. M. Odukalets,
and Yu. V. Lukichev
Translated from Novye Ogneupory, No. 4, pp. 6 – 10, March, 2007.
Original article submitted September 11, 2006.
A study has been made of the causes of failure in MLS-62 refractories made by the Zaporozhogneupor Com
pany in order to increase the resistance of the lining in a lime-regenerating rotating oven at the caustic and
lime regeneration process for cellulose at the Arkhangel(sk Cellulose and Paper Corporation. Ways are indi
cated of using measures to increase the period between repairs in the rotating oven.
In 2004 – 2005, the Zaporozhogneupor Company supplied
MLS-62 components for lining rotating ovens for caustic
treatment and lime regeneration in cellulose production at
Arkhangel(sk Cellulose and Paper Corporation. Table 1
gives the physicochemical parameters of the MLS-62 com-
The lime produced in the rotating ovens is a basic com-
ponent in making cellulose, and fault-free oven operation
governs the stability in producing lime, so to determine ways
of increasing the working life of the MLS-62 components we
examined the causes of failure in the lining of lime-regene
rating ovens (LRO).
In December 2005, during a shutdown at LRO No. 4, ex
perts from the two companies examined the state of the lin
ing in relation to changing it in the firing zone. It was found
that the lining in the firing zone was coated with an uneven
hummocky shell of regenerated lime with thickness from 50
to 400 mm; along the firing zone, this occurred to 70 – 95%
of the surface of the refractory lining, while at the surface of
the open refractory stack there were fractures (of depth
20 – 30 mm at some points), with displacement in the axial
and radial directions not observed; the residual thickness of
the components after 12 months of operation was from 120
to 170 mm with an initial thickness of 230 mm.
For comprehensive analysis, we selected specimens of
the MLS-62 components after service and lining coating.
Visual examination of the cross section showed a notable
zonal structure. There were three zones: the least altered of
thickness 70 – 100 mm, which retained a natural pale cream
color of the MLS-62 components; the transitional zone of
thickness 30 – 40 mm of brown color; and the working zone
(of maximum temperatures) of thickness 20 – 30 mm of
yellow color and with consolidated structure.
From each zone we prepared specimens with a diamond
tool for determining the open porosity P
, the apparent den
, the temperature for the start of softening under a
load of 0.2 MPa, namely T
, the thermal expansion coeffi
cient (LEC), the relative linear extension under load Dl/l
the compressive strength s
, and the chemical and phase
compositions. When the specimens were prepared from the
working and intermediate zones, we observed internal cracks
there, while no cracking was evident in the least altered zone.
The specimens for determining Ð
by drilling from each zone with a hollow diamond drill as
cylinders of diameter 36 mm and height 40 mm, while to de
Refractories and Industrial Ceramics Vol. 48, No. 1, 2007
1083-4877/07/4801-0012 © 2007 Springer Science+Business Media, Inc.
Zaporozhogneupor Company (Ukraine), Bruker AXS GmbH
(Germany), Trade Group Refractories Ltd, and Arkhangel’sk Cel
lulose and Paper Corporation Ltd. (Russia).
TABLE 1. Physicochemical Parameters of MLS-62 Components
Parameters From GOST 24704 Actual (mean value)
Mass fraction, %:
> 62 63.87
Open porosity, %
Compressive strength, MPa
Temperature for start of
softening under load, °C
Additional linear shrinkage,
%, at 1500°C