MECHANIZATION AND AUTOMATION
UDC 621.926.77.002
NEW EQUIPMENT FOR MILLING DOLOMITE
V. N. Khetagurov,
1
E. S. Kamenetskii,
1
and M. V. Gegelashvili
1
Translated from Steklo i Keramika, No. 1, pp. 17 – 18, January, 2003.
A centrifugal mill MV intended for milling non-plastic materials has been designed, undergone industrial test
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ing, and has been implemented at several factories.
Mechanical destruction of solid materials intended to re
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duce their size and separate them into components is often
applied in different industrial sectors and is one of the most
important operations in preparing materials for further pro
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cessing. Lump dolomite is subjected to several operations at
glass-making factories: crushing to the size of pebble, mill-
ing the crushed product to a dust-like state, and subsequent
screening of the milled product, milling being the least effec-
tive operation. The reason for this is imperfect milling equip-
ment used at the factories, which restricts their possibilities
and prospects.
At present machinery for grinding mineral materials to
obtain close-grained factions is mostly based on ball and rod
drum mills and to a much lesser extent on hammer crushers,
which have certain drawbacks. All drum mills use the same
principle of destroying material at the expense of energy of
milling bodies dropping and rolling inside the drum, which
are usually steel rods or steel balls raised to a certain height
by the drum revolving at a small angular velocity. Since only
an insignificant part of the energy imparted to milling bodies
is used directly for material breaking, whereas the major part
is consumed in wear of the milling bodies and the drum lin
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ing or transmitted into heat, the efficiency of the milling pro
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cess is low.
Ball mills have the following drawbacks: a high level of
electricity and metal consumption; contamination of the tar
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get product with iron; a cumbersome design of mills, which
makes it necessary to install them on heavy foundations; the
difficulty of controlling the milling process; strict require
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ments imposed on initial material moisture (in the case of dry
milling). It should be noted as well that for the mill to be effi
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cient, the maximum size of loaded components has to be lim
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ited (not more than 20 mm). However, a material with such
particle size easily absorbs atmospheric moisture and rapidly
transforms into a clay-like mixture even in short-term sto
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rage in open air, whereas moisture removal involves addi
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tional expenses related to preliminary drying.
The North-Caucasus State Technological University
(CKGTU) has developed a new method for self-crushing of
materials (RF patent No. 2078613), according to which the
milled material is formed as a vertical cylindric column. Its
lower part rotates with a peripheral velocity of 10 – 70 m/sec
and the pressure of material on this part of the column is
maintained equal to 0.005 – 0.045 MPa. Grinding of material
is implemented in the lower part of the column due to mutual
collision of particles and lumps against each other and their
subsequent abrasion in the upper layers of the column. This
method has been implemented in the development of a cen-
trifugal vertical mill (RF patent No. 2084787).
The MV mill (Fig. 1) consists of a vertical cylindrical
body 1 and a coaxially located shaft 2 inserted in bearings 3
Glass and Ceramics Vol.60, Nos.1–2, 2003
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0361-7610/03/0102-0019$25.00 © 2003 Plenum Publishing Corporation
1
North-Caucasus State Technological University (SKGTU), Vladikavkaz,
Russia.
1
10
6
7
5
12
3
2
4
14
15
11
8
9
13
Fig. 1. Scheme of vertical centrifugal mill.