SCIENTIFIC RESEARCH AND DEVELOPMENTS
STRUCTURE-MECHANICAL PROPERTIES OF PLASTICIZED MIXES
BASED ON HIGHLY CONCENTRATED CERAMIC BINDING
SUSPENSIONS (HCBS) OF HIGH-ALUMINA CHAMOTTE
V. A. Doroganov
and Yu. E. Pivinskii
Translated from Novye Ogneupory, No. 12, pp. 62 – 68, December, 2004.
Original article submitted August 19, 2004.
Plastic mixes based on high-alumina chamotte HCBS and a multifractional refractory filler are prepared; the
mixes molded at low pressures (30 MPa) make it possible to obtain materials with an initial porosity of
14 – 15%. This effect is attained by adding a composite plasticizer (a refractory clay and a complex
organomineral thinner) to the mix.
Highly concentrated ceramic binding suspensions
(HCBS) and HCBS-based plastic (plasticized) mixes are
promising in the technology of unshaped refractories [1 – 4].
From this standpoint, of special interest are high-alumina
Efficiency of composite additives. It was shown in 
that a highly dispersed refractory clay and a complex
organomineral thinner (COMT) (composed of sodium
tripolyphosphate and SB-5 organic plasticizer) when added
to the high-alumina chamotte (75% Al
) HCBS produced
an exceptional thinning and plasticizing effect. Relevant il
lustrative data are shown in Figs. 1 and 2. The difference in
porosity of green specimens free of COMT (Fig. 1a,
curve 1 ) and containing COMT (curve 2 ) amounts to 2.5%.
As the concentration of clay C is raised, the difference tends
to increase, and at C = 3%, it reaches 8%. This difference is
likewise retained in specimens heat-treated at 1000 and
1300°C (Fig. 1b and c). The compressive strength of green
and heat-treated specimens is likewise controlled by the clay
concentration (Fig. 2). In clay-free specimens, the compres
sive strength s
does not differ much, 20 and 22 MPa
(Fig. 2a, curves 1 and 2 ). With increase in C, curves 1 and 2
behave in a different manner; their course is quite clear and
does not need detailed comment. Relationships compressive
strength versus concentration C for heat-treated specimens
are shown in Fig. 2b and c).
It was noted in  that the high efficiency of the compo-
site additive (COMT + refractory clay) is due to its ability to
reduce the amount of kinetically bound liquid in HCBS-based
Elastoplastic viscous properties. Introducing highly
dispersed refractory clays into “lean” HCBSs provides a
route towards plastic mixes with quite satisfactory molding
properties at relatively low molding pressure [1, 4]. The con
centration of plasticized HCBSs may vary within 35 – 45%
(by weight) or within 40 – 55% (by volume) depending on
the HCBS granular composition, molding pressure, etc. In
analogy with refractory castables [4, 6], the moldability
(placeability) of plastic mixes is mainly controlled by rheo
logical properties of the matrix. Therefore it was of interest
to explore rheological properties of HCBS in a flow state 
and in a plastic state which is attained by partial dehydration
of precursor HCBS.
Our goal in this work was to study in some detail
elastoplastic viscosity and structure-mechanical properties of
precursor HCBS (free of additives) and HCBS containing
additives COMT and refractory clay. Structural and mechani
cal properties of plastic mixes are typically characterized in
terms of the yield limit, elasticity, plasticity, and plastic vis
cosity [7 – 9].
Refractories and Industrial Ceramics Vol. 46, No. 2, 2005
1083-4877/05/4602-0120 © 2005 Springer Science+Business Media, Inc.
V. G. Shukhov Belgorod Technological University, Belgorod,
Russia; Kerambet R&D Joint-Stock Co., St. Petersburg, Russia.