STUDY OF CERTAIN FACTORS
IN THE WEAR OF GRINDING BALLS DURING SERVICE
M. I. Timokhova
Translated from Novye Ogneupory, No. 2, pp. 17 – 21, February, 2013.
Original article submitted March 23, 2012.
New studies have shown that the main factors which affect the service life of grinding balls are the method and
parameters used to form them - quasi-isostatic pressing, the composition of the ceramic material, and its fine
ness after comminution. Another important factor is the regime used to bake the balls; the regime should en
sure the formation of a fine-crystalline structure in the baked products. A single-stage method is developed for
the quasi-isostatic pressing of grinding balls.
Keywords: quasi-isostatic pressing, elastic buffer, grinding balls, wear resistance, alundum-based material,
clay, mass-production facility, membrane die, single-stage pressing.
The method that we developed earlier  for the
quasi-isostatic pressing of ceramic and refractory products is
the most promising and economical of all currently-known
pressing technologies . The method provides for the
waste-free triaxial volumetric pressing of such products from
any powder materials that can be pressed . Quasi-isostatic
pressing can be classified as volumetric, triaxial, or radial
pressing and pressing with elastic dies , depending on the
configuration of the products being pressed and the scheme
used to apply the induced pressure to the material that is be
The main pressing element in quasi-isostatic pressing is
the elastic buffer. Polyurethane elastomer SKU-7l, made by
casting, has been selected as the main structural material of
the elastic pressing elements that are used in the technology.
Such elements ensure creation of the conditions necessary
for the compaction of powder materials and provide for reli
able performance of the molds in the production of pressed
products under factory conditions. The main requirements
that the material which is used for buffers in quasi-isostatic
pressing must satisfy were set forth in .
The method of quasi-isostatic pressing has been used to
develop an industrial technology for the production of a wide
variety of high-quality products. The products are pressed
from a whole range of plastic and nonplastic ceramics and
refractories, including corundum-based materials with an
content of 95 – 99.7% .
A highly productive automated industrial process has
been developed for making grinding balls by the above-de-
scribed pressing technology. The automated press which is
used has a productivity of 360 – 400 balls/h, and it has also
been tested for operation at a speed of 600 balls/h . The
grinding balls have excellent physico-mechanical properties
and are highly resistant to abrasion.
In connection with the low wear resistance of the grind-
ing balls produced by Russian industry, it was found neces
sary to search for a more wear-resistant material when devel
oping the quasi-isostatic pressing technology. The literature
data on the chemical composition of the bulk ceramics used
to make grinding balls is very fragmentary. However, it does
show that their composition is based on aluminum oxide.
The aluminum oxide content of the ceramics fluctuates from
90 to 99%. The ceramics also contain mineralizers, but their
concentrations were not reported. An alundum-based mate
rial that is employed at plants engaged in mass production
was thus also chosen for use in our studies. The material has
content of 92% and a clay content of 8%. Oxides of
yttrium, lanthanum, chromium, and nickel and magnesium
chloride were added to the alundum-based material to act as
mineralizers. Table 1 shows the chemical composition of the
Specimens of grinding balls made of materials of the
above compositions were wear-tested in a laboratory plane
tary mill that is the most effective piece of equipment for the
comminution of powder ceramic materials. Its efficiency is
comparable to the efficiency with which ceramics are ground
in industrial ball mills.
Refractories and Industrial Ceramics Vol. 54, No. 1, May, 2013
1083-4877/13/05401-0025 © 2013 Springer Science+Business Media New York