A STUDY AND COMPARATIVE ASSESSMENT
OF THE THINNING EFFECT IN DEFLOCCULANTS.
PART 1. BAUXITE-BASED HIGHLY CONCENTRATED
CERAMIC BINDING SUSPENSUONS (HCBSs)
Yu. E. Pivinskii,
Pavel V. Dyakin,
and Petr V. Dyakin
Translated from Novye Ogneupory, No. 7, July, 2004, pp. 27 – 36.
Original article submitted April 10, 2004.
The thinning efficiency of deflocculants (dispersing aluminas ADS, ADW-1, M-ADS1, M-ADW1and their
binary mixtures; commercial dispersants Giessfix, Dollafax, Costament, and organomineral additives) was
tested on bauxite-based HCBS specimens. The thinning efficiency of additives (measured by the decrease in
viscosity at low shear rates) is different; the best effect was observed in Giessfix 162 and M-ADS1 dispers
In the technology of slip-cast ceramics and refractory
castables, an issue of major concern is preparation of these
materials with minimum moisture content and their retention
of specified rheological properties [1, 2]. In this connection,
much effort has been focused on the development and appli-
cation of various dispersing and deflocculating additives in
the past years [3 – 11].
Our goal in this work was to study the thinning effi
ciency of additives that have found application in the tech
nology of ceramics and castables. The object of study were
bauxite-based highly concentrated ceramic binding suspen
The original (intact) systems on which the efficiency of
thinning agents (deflocculants) was tested were HCBSs
based on bauxite and 90% bauxite + 10% highly dispersed
quartz glass (HDQG). The HCBSs based on bauxite +
HDQG have found application in the technology of high-alu
mina ceramic castables, and bauxite-based HCBSs — in the
preparation of sintered ceramics . For preparation of the
original HCBSs of all types, Rota HD-grade bauxite (avail
able from China) was used; it was fired in a rotary kiln and
had a composition 89 – 91% Al
+ <4% SiO
original materials were wet-ground in a ball mill lined with
uralite (75 – 77% Al
) using grinding bodies of the same
composition. To assist the wet grinding of quartz glass con-
taining-HCBSs (Table 1, No. 3), some liquid glass (0.03%)
was added. The bauxite suspensions (see Table 1, Nos. 1 and
2) were prepared using a complex organomineral thinning
agent (COMA) at a concentration of 0.1 – 0.2%. All wet-
ground suspensions had pH=8–9. Characteristics of the
original suspensions are given in Table 1; integrated curves
for granular distribution of solid-phase particles are shown in
Fig. 1. HCBSs No. 1 and 3 show a comparable dispersity.
Bauxite suspension No. 2 has a somewhat higher dispersity.
Based on these HCBSs, one can prepare a densely sintered
ceramic at 1400 – 1420°C .
The suspensions in Table 1 show comparable values of
, but differ appreciably in d
(for HCBSs No. 2
and 3). Despite the high volume concentration of solid phase,
HCBS No. 3 exhibits a smaller viscosity at low shear rate
(3 – 9 sec
). An explanation of the fact should be sought in
the involvement of HDQG (which plays the role of a stabi
lizer ) and rather short aging time.
Suspensions of this type differ in
which is a func
tion of the porosity P
. Despite the fact that the
HDQG-containing suspension (No. 3) has a high volume
= 0.70), its relative concentration index n
(defined as the ratio C
has a low value (n
Refractories and Industrial Ceramics Vol. 45, No. 5, 2004
1083-4877/04/4505-0343 © 2004 Springer Science + Business Media, Inc.
Kerambet R&D Joint-Stock Co., Obninsk, Russia; St. Petersburg
State Technological Institute (Technical University), St. Peters