THINNING OF ARGILLACEOUS SUSPENSIONS
O. A. Slyusar’,
V. A. Doroganov,
and V. M. Uvarov
Translated from Novye Ogneupory, No. 8, pp. 40 – 42, August, 2016.
Original article submitted March 15, 2016.
The change in rheological parameters of refractory clay is shown in relation to different additive concentra
tion. Processes of commercial grade lignosulfonate adsorption on clay particles within the composition of
complex additives are considered. It is established that the amount of absolute lignosulfonate adsorption,
added to a complex, is greater than with addition of pure lignosulfonate. The efficiency of using a complex
containing lignosulfonate as a diluting additive for refractory clay is demonstrated.
Keywords: clay, adsorption, addictive, mobility.
During production of refractory objects, ceramics, and
concretes there is extensive use of aqueous suspensions of
clay, kaolin, etc. Various additives are used in order to reduce
moisture content, and improve rheological properties of sus-
pensions [1 – 8]. In particular, in producing refractories
lignosulfonate is often used, capable of increasing molding
mix plasticity, density, and strength of finished objects .
However, use of these additives does not provide significant
thinning of kaolin and clay suspensions, required for produc-
ing objects by casting technology. In addition, as practice
shows for thinning ceramic mixes it is expedient to use a set
of different additives [10 – 12]. In spite of the variety of
them a requirement still exists for more effective and inex
pensive additives capable of providing maximum mobility
with minimum suspension moisture content.
The aim of this work is to study the effect of different
combined additives containing soda, commercial grade
lignosulfonate (LST), and sodium tripolyphosphate (TPP) on
rheological and absorption properties of refractory clay. So
dium tripolyphosphate and soda are typical thinners for ce
ramic slips, and lignosulfonates are added to ceramic mixes
during plastic molding, which makes it possible to increase
green mix plasticity and the strength of finished objects .
Additions were made to argillaceous suspensions con
taining 82% dry substance. Rheological curves were ob
tained by means of a Reostat-2 instrument for a suspension
with additives, and rheological parameters were determined
from them, i.e., plastic viscosity h
and limiting dynamic
shear stress t
. Results of studies are provided in Table 1.
The thinning capacity of TPP, LST, and soda, used as in-
dividual additives is significantly lower than in the case of
using complexes, which is confirmed by results of previous
research [10 – 12]. In addition, use of lignosulfonate com-
bined with sodium tripolyphosphate (in the ratio 1:4) makes
it possible to reduce consumption of such an expensive elec-
trolyte as tripolyphosphate. Introduction of a complex in an
amount of 0.15% is most effective. The t
is reduced to 30
MPa, and h
to 0.07 Pa·sec. Use of TPP alone without LST
in an amount of 0.15% makes it possible to reduce t
60 Pa, and h
= 0.10 Pa·sec. Addition of LST alone in an
amount of 0.15% reduces t
to 410 PA, and h
0.64 Pa·sec. Combined additives containing soda and LSR
(in the ratio 4:1) are not so effective since with 0.15% of this
only decreased to 380 Pa, and h
to 0.47 Pa·sec.
However, in this case it is possible to observe the preferred
complex over individuals.
Adsorption of LST on clay particles has been studied by
the change in concentration of test substances after establish
ing adsorption equilibrium. Concentration was determined
by a photometric method by means of an SF-46 spectrome
ter. Solutions were prepared with known concentration of ad
sorbate, and to each solution a sample of adsorbate was
added and stirred for 30 min. It is impossible to determine
adsorption of sodium tripolyphosphate and soda by photo
metric determination since in this system they do not have
separate adsorption ranges, and therefore further discussion
is of a circumstantial nature.
Refractories and Industrial Ceramics Vol. 57, No. 4, November, 2016
1083-4877/16/05704-0410 © 2016 Springer Science+Business Media New York
FGBOU VPO Belgorod V. G. Shukov State Technological Uni
versity, Belgorod, Russia.