EFFECT OF ADDITIVES ON DISPERSED SYSTEM
O. A. Slyusar’,
R. N. Yastrebinskii,
N. I. Cherkashina,
V. A. Doroganov,
and A. V. Yastrebinskaya
Translated from Novye Ogneupory, No. 12, pp. 32 – 34, December, 2014.
Original article submitted July 2, 2014.
Results are provided for a study of the effect of complex additives on critical concentration for argillaceous
suspension structure formation. Curves are presented for the dependence of suspension limiting dynamic
shear stress on solid phase content and additive concentration. It is revealed that the most effective complexes
at low concentration are those containing oxyphenolfurfural oligomers. These complexes may be used as di
luting additives for argillaceous suspensions.
Keywords: complex additive, suspension, structure formation, limiting dynamic stress, aggregative stability.
Refractory objects and materials are used extensively in
production of cast iron and steel for lining vessels for accu-
mulating and transporting molten metal, furnaces for billet
heating, production units, etc.
As is well known, one of the main forms of raw material
for refractory objects is refractory clays and kaolin. The
properties of finished objects depend on properties, quality,
and raw material mixture manufacture. For refractories man
ufactured using dispersed systems (slip, suspension) it is
very important to control structure formation. Diluting addi
tives and are used in order to prepare a suspension with mini
mum moisture content and adequate mobility. Research has
shown [4 – 10] that use of complex additives is promising,
containing traditional electrolytes: water glass, soda, and
also sodium tripolyphosphate (STPP), oxyphenolfurfural oli
gomers, and superplastisizer C-3.
As follows from published sources [11, 12] in determin
ing the ratio of suspensions of dispersed phase and disper
sion medium a sharp change is observed in system
physicochemical properties, characterizing transition of a
system from freely dispersed to structured. Surface tension
forces start to predominate in a system between particles un
der forces of repulsion, and coalesced spatial structures are
formed, within which dispersed phase particles are con
nected through fine residual liquid interlayers. Curves for the
dependence of physicochemical parameters of a system on
dispersed phase content (or dispersion medium) in clay sus-
pensions have a break point corresponding to the start of
structure formation. Dispersed phase concentration, with
which this transition is observed, is called the structure for-
mation critical concentration (SCC). In ceramic technology
the idea of “optimum moisture content” is used, i.e., the min-
imum of dispersion medium with which a sharp change is
observed in system physicochemical parameters, corre
sponding to structure breakdown. For comparative character
istics of a suspension of different composition it is more cor
rect to compare parameters close to the SCC region.
We have studied the effect of complex additives on criti
cal concentration of suspension structure formation for re
fractory clay. The complexes used: STPP+C-3, STPP+SB-5
(product of concentration of the bottoms of resorcin produc
tion with furfurol), STPP+SB-FF (product of fluoroglucine
condensation with furfurol), STPP+reotan. The ratio of com
ponents in complex additives was 4:1 respectively. The ef
fect of complex additives on clay suspension rheological pa
rameters was studied in a Reotest-2 rheometer. A parameter
specifying the start of structure formation used was limiting
dynamic shear stress t
. Suspensions were prepared with dif
ferent solid phase content.
The effect of solid phase content in a suspension on lim
iting dynamic of an argillaceous suspension with additives
and with different concentrations of complex additives is
Refractories and Industrial Ceramics Vol. 55, No. 6, March, 2015
1083-4877/15/05506-0562 © 2015 Springer Science+Business Media New York
FGBOU VPO V. G. Shukov Belgorod State Technological Uni
versity, Belgorod, Russia.