GENERAL ASPECTS OF PERICLASE-CHROMITE REFRACTORY WEAR
DURING NICKEL PRODUCTION
D. A. Tereshchenko,
A. A. Platonov,
G. R. Platonova,
E. F. Chaika,
and I. G. Maryasev
Translated from Novye Ogneupory, No. 6, pp. 110 – 113, June 2011.
Original article submitted May 12, 2011.
A system of microscopic and physicochemical analysis methods is used to study a number of periclase-chro-
mite composition objects. Microstructural changes of refractories during service in heating units for nickel
preparation are studied from the results obtained.
Keywords: refractories, periclase-chromite, petrography, metallurgy, nickel.
Production of nickel is one of the most promising areas
in Russian nonferrous metallurgy. It is possible to assess the
level of economic development of the country from the vol-
ume of production and demand for nickel. The main raw ma-
terials in production of nickel are oxide and sulfide ores. Pro-
duction of nickel from ore includes several starting material
processing stages with preparation in each of them of the
corresponding semifinished product: nickel concentrate,
nickel and (or) copper-nickel converter matte. The quality of
refractory lining for heating units in nickel production is one
of the governing factors affecting the operating life of a unit
and its productivity, and also preparation of high quality final
product. The lining of heating units for smelting nickel is
made predominantly of chromium-containing refractory ob-
jects. Apart from chemical reaction with the product being
processed and wear by moving melt, the lining experiences
stresses caused by a temperature drop (thermal shock), and
action of mechanical loads from the reactive pressure of the
furnace body, systematically repeating mechanical loads
combined with a thermal load in the area of supporting struc-
Petrographic study of a number of periclase-chromite
refractories after service in nickel production converters
makes it possible to establish precisely and interpret clearly
the expressed multizonal structure. The thickness of the
zones formed in refractory depends on specific conditions
and service duration.
As a rule within the cold part of refractory objects the
least changed zone is retained with a thickness of 40 – 50 to
150 – 160 mm, exhibiting similar microstructural character-
istics to objects before service.
Between the hot and cold ends of refractory there is often
a transitional zone with thickness of not more than 40 mm,
which forms as a result of oxidation of sulfides present in a
melt. By oxidizing, sulfides are converted into sulfates with
an increase in volume, which promotes disintegration of the
refractory microstructure, generation and development of a
large number of variously directed cracks in this zone. The
hot part of a worn object is a working zone with a thickness
from 30 to 80 mm, within which microstructural and chemi-
cal changes of refractory are due mainly to filling of pore
space with molten metal and slag components, and their re-
action products with refractory components. Compaction is
typical for the working zone and the microstructure becomes
monolithic, and regeneration of refractory components. As a
rule the working zone may be separated into several layers
differing with respect to chemical composition (Tables 1 and
2), forming as a result of the highly corrosive chemical ac-
tion of flowing molten matte and slag of iron silicate sulfide
composition. Exhibiting low viscosity, the melt starts to pen-
etrate actively through the pore space into the depth of re-
fractory. Impregnation is primarily by the most readily-melt-
ing sulfide components (melting temperature of sulfide solid
solution 700 – 1000°C), which penetrate into the refractory
to a distance up to 80 mm, forming a deep layer with sulfide
impregnation, and this is in contact with the transition layer.
The base of the sulfide mass in this layer is iron-nickel sul-
fide (bravoite [Fe,Ni]S
and pentlandite [Fe,Ni]
iron-copper sulfides (bornite Cu
), and rarely encountered copper sulfide (chalcocite
S) and nickel sulfides (polydymite Ni
, millerite NiS).
Refractories and Industrial Ceramics Vol. 52, No. 3, September, 2011
1083-4877/11/05203-0212 © 2011 Springer Science+Business Media, Inc.
OOO Gruppa Magnezit, Satka, Chelyabinsk Region, Russia.