TEMPORARY TECHNOLOGICAL BINDERS IN INDUSTRY
K. G. Zemlyanoi
Translated from Novye Ogneupory, No. 10, pp. 13 – 18, October, 2012.
Original article submitted February 17, 2012.
The use of temporary technological binders in metallurgy and the refractories industry is considered and re
sults from pilot-plant tests of new domestically produced organic binders are presented.
Keywords: binder, agglomeration, surface-active substance, structure, strength, density
Processes of compactification (extrusion, briquetting,
pelletizing, agglomeration) play an enormous role in a whole
series of industrial branches, in ferrous and nonferrous met
allurgy, the construction materials industry, and the ceramic
and refractories industry. The initial substances are generally
nonplastic, for example, ores in oxide and sulfide forms, ore
concentrates, nonmetalliferous natural materials, synthetic
materials, and industrial dust. The function of technological
binders is to assure the effectiveness of extrusion of semifin-
ished products by lowering the internal friction in the com-
pressed system and the friction against the wall of the mold
as well as assure the coherence of the compressed system af-
ter the molding force has been removed.
In the course of molding finely dispersed powders, the
unevenness of the density distribution in the body of the bri
quette, the internal stresses, and, consequently, fracturing as
a result of the phenomenon of elastic expansion are all great.
The process of improving the briquetting process proceeds
basically in two directions, the first of which involves reduc
ing the friction of the particles against the wall of the mold
and the interparticle friction to assure a uniform density dis
tribution and increase the mobility of the particles under
pressure. In the second direction the design of the mold is de
veloped to obtain large finished briquettes and assure the ab
sence of defects in the briquettes.
From the studies carried out by P. A. Rebinder, et al. ,
it follows that the medium in which deformation of the mate
rial occurs may actively participate in the deformation pro
cess, facilitating this process if there are surface-active sub
stances present in the medium in optimal quantities, thereby
making it possible to obtain denser pressed parts under the
The density of stowage of friable materials in free back
filling as well as under the effect of different external factors
depends not only and often not even so much on the sub
stance of the particles of the friable material, as on the di-
mensions, shape, and state of the surface and structure. The
cohesive forces that arise as the particles come together in-
crease markedly by comparison with their mass (force of
gravity) with decreasing dimension of the particles of a pow-
der. Particles of small dimensions, therefore, readily form
porous coagulation structures, such as unordered networks
that hinder the uniform distribution of particles in a volume
and their dense stowage.
Even weak van der Waals cohesive forces are sufficient
to assure the strength of friable arched formations that hinder
consolidation (Fig. 1). Adsorbed layers of surface-active
substances or water migrate along the surface and create a
two-dimensional pressure that usually proves to be higher
than the strength of point contacts at the boundaries of an ad
sorbed layer, as a result of which the system enters a compact
state with coagulation contacts (Fig. 1b ).
In actual practice this phenomenon manifests itself in the
form of different types of “fluidity” of friable materials.
Refractories and Industrial Ceramics Vol. 53, No. 5, January, 2013
1083-4877/13/05305-0283 © 2013 Springer Science+Business Media New York
FGAOUVPO VPO Ural Federal University, Yekaterinburg, Russia.
Fig. 1. Coagulation structure: a) primary porous structure; b ) con