REFRACTORIES IN HEATING UNITS
EFFECTIVE HIGHLY RESISTANT WAELZ KILN LININGS
V. V. Slovikovskii
and A. V. Gulyaeva
Translated from Novye Ogneupory,No.8,pp.3–7,August 2014.
Original article submitted June 6, 2014.
Conditions are analyzed for service of Waelz kiln linings of the Chelyabinsk Electrolytic Zinc Plant and the
Ust’-Kamenogorsk Lead and Zinc Combine, and the main reasons for refractory wear are revealed. Refractory
grades PKhPP and KhPT are most resistant for service conditions in Waelz kiln linings. In order to improve
Waelz kiln lining life chromite-periclase heat-resistant refractory lining schemes are developed and intro
duced, a high-temperature adhesive is developed, impregnation of refractories with coal-tar pitch is accom
plished, and a test batch of objects is prepared and tested in a Waelz kiln lining. A laying mortar based on
self-propagating high-temperature synthesis is developed. Spatial geometric shapes, optimum dimensions, ce-
ramic object structure, and layups based on them are studied. Linings are tested in the Waelz kilns of a number
Keywords: refractory object spalling, thermal stresses, chromite-periclase heat-resistant refractories,
refractories based on fuzed grains of periclase-chromite composition, self-propagating high-temperature syn-
thesis, laying mortar.
The Waelz process is used in order to extract zinc from
production waste, containing zinc in oxide and partly sulfide
form. This is a process of volatilizing valuable components
in a rotary kiln with heating of starting material to a tempera
ture below that of its melting point. The main raw material is
cake and slag, and sometimes dust and zinc ore are added.
The reducing agent used is coke fines in an amount of
50 wt.% of a charge.
The Waelz process is carried out in tubular kilns
40 – 90 m long and 2.5–5m in diameter. Within the Rus
sian Federation kilns are mainly used with a size of
3.6 ´ 50 m (large) and 2.5 ´ 41 m (small). As a rule the body
of a kiln is supported by two or three roller supports.
Overseas different types of Waelz kiln operate. In the
Bulgarian National Republic two-support kilns are used with
a size of 2.5X41 m. In the Polish metallurgical plant in
Miasteczko Œl¹skie a five-support Waelz kiln is used 4.2 m
in diameter and 95 m long, and in Boles³aw it is 40 m long
The firm KHD Humboldt Wedag has constructed a
Waelz unit in Zambia for extracting zinc and lead from waste
rock. Within the complex there are two rotary kilns 75 m
long and 4.5 m in diameter, and one kiln with a size of
3.2 ´ 40 m. The smallest kilns in Japan are 30 – 38 m in
length and 2.0 – 2.5 m in diameter.
In the practice of operating large Waelz kilns it is well
known that campaign duration depends on many factors, the
main ones of which are:
– starting material variable moisture content;
– starting material composition irregularity;
– production regime irregularity;
– degree of material corrosiveness;
– refractory life.
It has also been established that the life of refractories of
a two-support kiln is lower than for a three-support kiln. This
is explained by presence of bending moments, which in a
two-support kiln are somewhat less than in a three-support
kiln. Curvature of the kiln geometric axis causes action of
cyclic loads on a lining and its breakdown.
The refractory lining in Waelz kilns experiences apart
from thermal shock constant chemical and mechanical action
of the charge being treated and Waelz process products. The
latter are present in different phase compositions: solid
(clinker, coke), liquid (molten iron silicate, matte), and gas
Refractories and Industrial Ceramics Vol. 55, No. 4, November, 2014
1083-4877/14/05504-0277 © 2014 Springer Science+Business Media New York
FGAOU VPO Ural Federal University, Ekaterinburg, Russia.