VIBRATING
MILLS
Operating
principle:
The material passes the cylinder along a
helical path with transportation being primarily a
result of displacement. Due to the effect of vibration,
the material is directed to the outlet. The
grinding cylinders which perform almost circular move- ments by the effect of unbalanced weights,
are filled with grinding media to 65 vol.%. In general, reduction by impact forces is predominant in the Palla mill. Possible
grinding cylinder connections as shown hereunder
Particle sizes
and throughputs:
Feed size : from 1 to 25mm
Final fineness: 100 to 2mm by direct
grinding
- and 30 - 100 - in closed circle with
sieving machine or air classifier
Throughputs: from 100kg/h up to .
25t/h (depends on the product to be grinded)
Advantages :
· reduced space
requirements
· low energy
consumption
· reduced installation
costs; direct installation on factory soil
possible
· especially
interesting in case of explosive products, because
filling grade grinding medias + product is
about 95 vol. %
· easy adjustment of
the amplitude (up to 12 mm)
· wear minimised,
impact grinding
· possibility of
iron-free grinding by using ceramic
grinding media and inner liner
· reduced and easy
maintenance,
bearings are fastened in the webs in such a
manner that the
complete unbalanced-type drive can be easily
removed.
· grinding media only
need to be refilled
· excellent
homogenizing of the product
· no air production,
consequently no need of a filter
(cost reduction)
· direct cardan drive
FIELDS
OF APPLICATION
AUBEMA
Vibrating Mills are used for grinding
of
almost all materials in the processing industry,
from
medium-sized lumps up to finest grains. The
particular
fields of application are coal, chemicals,
ceramics
and pit and quarry industries, including
their
subgroups.
FEED
MATERIALS
Lignite,
hard coal, ash, coke, charcoal, dolomite,
marble,
silica sand, limestone, bentonite, lime,
gypsum,
puzzolan, bauxite, copper granules, iron
oxide,
ferrosilicon, magnesium oxide, arsenide,
aluminium
oxide, silicon carbonate, zirconium,
fireclay,
corundum and similar products.
Twin-
Tower
Mills:
As
tumbling mills such as ball and rod mills are not very effective in fine
grinding due to due to their loe power intensity, alternatives for fine and
ultra fine grinding are tower mills and stirred mills. In contrast to tumbling
mills where motion is imparted to the charge via the rotational mill shell, in
tower and stirred mills motion is imparted to the charge by the movement of
internal strirrer while the shells are stationary.
Construction:
In a
tower mill steel balls or pebbles are placed in a vertical grinding chamber in
which an internal screw flight provides medium agitation. The feed enters at
the top, with mill water, and is reduced in size by attribution and abrassion
as it falls, the finely ground particles being carried upwards by pumped liquid
and overflowing to a classifier. Over sized particles are returned to the
bottom of the chamber, and the final classification is by hydrocyclones, which
returned underflow to the mill sump for further grinding.
Advantages:
Its
instalation area is small
Its
noise level is low
Its
energy usage is efficient
It
shows minimal overgrinding
its
capital and operating cost is low
Capacity:
Its
capacity is 100t/h with the product size of 1-100 micrometers
It can
grinde a variety of material like limestone, silica, rock salt, coal and copper
concentrates
References:
Will's
mineral processing technology By Barry A. Wills
Wikipedia.org
www.AUBEMA.com
