SCIENTIFIC RESEARCH AND DEVELOPMENT
RESEARCH IN THE AREA OF PREPARING MATERIALS
BASED ON FUZED QUARTZ HCBS.
PART 7. STUDY OF CENTRIFUGALLY MOLDED REFRACTORY
SINTERING AND CRISTOBALITIZATION
Yu. E. Pivinskii
and P. V. Dyakin
Translated from Novye Ogneupory, No. 9, pp. 16 – 24, September 2015.
Original article submitted July 17, 2015.
The effect of nonisothermal heating temperature in the range 1100 – 1500°C on shrinkage indices and and de
gree of cristobalitization is studied for quartz steel-pouring refractory specimens with a ceramic concrete
structure. Cristobalite formed at elevated temperature has a reduced (150 – 220°C) transition temperature into
the low-temperature form. Quartz steel-pouring refractories with a ceramic concrete structure have good ther-
mal shock resistance, and in contrast to corundum-graphite refractories, requiring preliminary high-tempera-
ture heating, may operate without the latter (“cold start”).
Keywords: fuzed quartz, HCBS, ceramic concrete, centrifugal molding, steel-pouring refractories, cristo-
balite, LTEC, firing shrinkage, porosity, ultimate strength in compression.
As noted in articles [1 – 4], recently production of quartz
steel-pouring refractories manufactured in OAO Dinur in ac
cordance with an OAO Kerambet-Ogneupory licence is ac
complished by ceramic concrete technology using a centrifu
gal molding method. This technology was developed and im
plemented in large-scale production as a result of many years
of research and production tests, and has been reflected in a
number of patents [5 – 11].
Compared with materials considered in previous articles
[12 – 14], the specific nature of the structure of centrifugally
molded quartz refractories, prepared on the basis of concen
trated casting systems with a high content of medium grained
filler, differs fundamentally with respect to fineness and
grain size distribution for particles of the semifinished prod
uct solid phase. In view of this it is important to study sepa
rately sintering, strengthening and cristobalitization of mate-
rials prepared by this technology.
AND FEATURES OF THEIR STRUCTURE
Detailed analysis of chronology for research, industrial
tests, and production stages of development work in the field
of centrifugally molded quartz refractories is provided in
publications [1 – 3, 15 – 18]. In the contemporary stage of
centrifugal molding technology development for objects
with a ceramic concrete structure use of fuzed quartz HCBS
with high density containing particles coarser than 63 mmof
about 15% is specified with subsequent introduction of a
granular polyfraction filler (crushed, disseminated, and de
magnetized fuzed quartz) with d
up to 1.5 mm in an
amount up to 50% [1, 3]. The molding system obtained in
this way has a self-sintering capacity with a moisture content
within the limits of 6 – 7%. Due to this with a centrifugal
molding process optimized with respect to speed and dura
tion it is possible to prepare semifinished products with a rel
atively uniform grain size composition throughout the thick
Refractories and Industrial Ceramics Vol. 56, No. 5, January, 2016
1083-4877/16/05605-0476 © 2016 Springer Science+Business Media New York
Part 1 of the article was published in Novye Ogneupory No. 7
(2014), and parts2–6inNos. 1, 3, 4, 6, and 7 (2015).
OOO NVF Kerambet-Ogneupor, St. Petersburg, Russia.
FGBOU VPO St. Petersburg State Technological University
(Technical University), St. Petersburg, Russia.