ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 9, pp. 1453!1456. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + D.V. Cherednichenko, E.V. Vorob’eva, N.P. Krut’ko, I.I. Basalyga, Yu.V. Matrunchik, 2007, published in Zhurnal Prikladnoi
Khimii, 2007, Vol. 80, No. 9, pp. 1416 !1420.
AND INDUSTRIAL INORGANIC CHEMISTRY
Effect of Binder Reagents of Varied Nature on the Strength
of Potassium Chloride Grains
D. V. Cherednichenko, E. V. Vorob’eva, N. P. Krut’ko,
I. I. Basalyga, and Yu. V. Matrunchik
Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received January 16, 2007; in final form, April 2007
Abstract-Specific features of structure formation in dispersed salt systems based on potassium chloride were
studied from the standpoint of a relationship between the physicochemical properties of binder reagents,
granulation conditions, and grain strength.
Granulated fertilizers have a number of advantages
in agriculture over those finely grained: lower dusting
and transportation loss, lower caking, higher agro-
chemical efficiency because of the decrease in wash-
ing-out of soluble salts from soil, etc. The compaction
and pelletization are widely used for granulation of
dispersed materials [1, 2]. In pelletization, the struc-
ture of a material is formed under dynamic conditions.
The uninterrupted motion of a material being granu-
lated, on the one hand, leads to formation and growth
of grains and, on the other hand, causes disintegration
of grains having the lowest strength. In the case of
simultaneous occurrence of these counteractive proc-
esses, grains close in shape, size, and properties are
formed. The pelletization efficiency can be improved
by controlling the dispersity of particles and the state
of their surface, which provides a compact [packing]
of particles and a higher number of contact points [2,
3]. The pelletization has a number of advantages over
compaction, the main of which is the lower specific
energy consumption and better product quality because
of the lower content of the dust fraction.
When using binder additives in order to raise the
granulation efficiency and improve the grain quality,
it is necessary to take into account the fact that
the mechanisms of contact interaction in compaction
and pelletization are different. Compaction at elevated
pressures and temperatures of finely grained potassi-
um chloride treated with binder reagents leads to for-
mation of a three-dimensional structure from the par-
ticles and to bulk densification of the material. Pelleti-
zation yields, as a result of treatment of the material
with binders or film-forming substances and the sub-
sequent drying, a layered structure in which particle
layers are attached to each other not only by crystalli-
zation3condensation contacts between particles, but
also by the binding action of an additive. In the gen-
eral case, use of additives in pelletization raises the
grain strength by a factor of 3 and more, whereas in
the case of compaction, this parameter can be only
raised by 20330% .
In granulation of KCl, the following features of dis-
persed salt systems should be taken into account: dis-
solution of the surface layer of KCl upon moistening
with binder solutions; surface hydrophobicity of pow-
dered fertilizers being granulated, caused by use of
organic reagents in dressing of potassium ores; etc.
In view of the fact that pelletization has not been
used as a method for potassium chloride granulation
and approaches to use of binders in manufacture of
granulated potassium fertilizers have been for the
most part empirical, a study of the relationship bet-
ween binder properties, conditions of structure forma-
tion in pelletization, and grain strength is topical.
Powdered KCl of chemically pure grade with an
average particle size of 0.5 mm was used in the study.
The following binders were used: polyethylene
glycol, molecular weight M =120 10
chemie, Germany) (P1); Na-carboxymethyl cellulose,
M =(435) 0 10
(P2); and polyacrylamide (PAA) of
Praestol brand (Degussa Eurasia Limited Liability
Company, RF), M ; 140 10
(P3). Oligomeric prod-
ucts of urea polycondensation with formaldehyde
[urea3formaldehyde resin (UFR), GOST (State Stan-
dard) 14231388] (Kh1) were also used.
Potassium chloride was pelletized on a laboratory