Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 2, pp. 333−336.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
V.F. Kurenkov, I.N. Nadezhdin, A.R. Sadykov, H.-G. Hartan, F.I. Lobanov, 2009, published in Zhurnal Prikladnoi Khimii, 2009,
Vol. 82, No. 2, pp. 339−342.
AND POLYMERIC MATERIALS
Stabilization of a Concentrated Suspension of Calcium Carbonate
with Cationic Praestol
V. F. Kurenkov, I. N. Nadezhdin, A. R. Sadykov, H.-G. Hartan, and F. I. Lobanov
Kazan State University of Technology, Kazan, Tatarstan, Russia
Ashland Eurasia Limited Liability Company, Moscow, Russia
Received February 14, 2008
Abstract—The sedimentation stability of a 60% suspension of calcium carbonate in the presence of various
commercial samples of cationic Praestol was studied, using a torsion balance, in relation to the concentration and
molecular weight of the polymer, concentrations of NaCl and CaCl
, and particle size of calcium carbonate.
It is well known [1–3] that the character of interaction
of dispersed phase particles, determining the stability of
mineral suspensions, strongly depends on characteristics
of polymers and disperse systems. Among various mineral
suspensions, calcium carbonate suspensions are of much
importance, as they are used in production of paper,
ceramics, sodium carbonate, and sugar. The behavior of
suspensions has been characterized in reviews
[4–6]. The effect of polymers on their stability is studied
inadequately, and the available data are contradictory.
Cationic Praestols, which are water-soluble copoly-
mers, show promise for controlling the stability of CaCO
suspensions. The effect of cationic Praestols on the
sedimentation stability of dilute  and concentrated 
suspensions was studied previously. However, in
 the polymer concentration was varied within narrow
%, and the inﬂ uence of the CaCO
size on the sedimentation was not taken into account.
In this study we evaluated the sedimentation stability
of a 60% CaCO
suspension in the presence of various
commercial samples of cationic Praestol in a wide
range of its concentrations, 0.003–0.06%, in relation to
the molecular weight of the polymer, NaCl and CaCl
concentrations, and CaCO
Studies were performed with cationic Praestols
[copolymers of acrylamide (AA) with N-acrylamidopropyl-
N,N,N-trimethylammonium chloride (APTMAC)]
(Russia–Germany). The characteristics of the copolymers
are given in the table. CaCO
was of pure grade [GOST
(State Standard) 4530–76], with the mean particle
= 0.1 mm. NaCl, CaCl
, and K
chemically pure grade. All solutions were prepared in
Samples C-2 and C-3 were prepared by degradation of
cationic Praestol 650 VS (C-1) in a 1% solution at 50°C
in the presence of potassium persulfate. The degradation
procedure was similar to that described previously .
By this procedure we obtained copolymer samples with
different intrinsic viscosity [η] and the same chemical
composition of the macromolecules (see table).
The content of ionic units in the cationic Praestol
was evaluated from the chloride content determined
mercurimetrically . The [η] values were found
from the results of viscometric measurements (VPZh-3
viscometer, capillary diameter d = 0.56 mm) in 0.5 M
NaCl at 25°C, from the linear concentration dependence
of the reduced viscosity η
[η] = lim(η
) at c
From [η] we estimated on the molecular weight of the
polymer M taking into account the Mark–Kuhn–Houwink
particles were fractionated with a VEB MLW
multilevel vibrating screen (Germany).