OBJECTIVES:
1. To determine the particle size
distribution of the coarse salt.
2. To observe the effect of speed and time
in grinding the coarse salt.
INTRODUCTION :
Ball milling process is introduces as a
process to reduce the particle size or in other grinding process. This process
is used to grind materials to small fine particles and is widely use especially
in the mineral dressing processes, paints and ceramics industries. The grinders
that are used are from different materials including the ceramic balls, flint
pebbles and stainless steel balls.
This process works by the effective speed
by which the balls rotating along with the cylindrical pot and an internal
cascading effect of the balls reduce the materials size to small powders.
MATERIALS AND APPARATUS:
- 300.4179 g of coarse salt
- Steel ball
- Ball mill
- Sieve nest
- Weighing balance
PROCEDURE:
1) 313.980 of coarse salts were weighed
2) Different sizes of steel balls were
inserted to the mill.
3) The weighed salts were inserted into
the mill.
4) The milling process was initiated with
the speed of 10 within 20 minutes.
5) The product obtained is then weighed
again after the milling process ended.
6) The powder obtained was sieved using
the sieving method with sieve nest.
7) Results data was
collected and a histogram was plotted.
RESULTS:
DISCUSSION:
Firstly, during weighing the course salts,
we may observed the reading wrongly. We also may insert different size of steel
ball into the cylindrical shell which may affect the reduction size as the
larger size ball will crush the particulates better compare to the smaller ball
size. Therefore, not all the coarse salts are reduced with same efficiency. We
also may not adjust the speed relatively with the time causing the coarse salts
not completely grind to even distribution of fines.
Other factors affecting the particles size
reduction process are the size of grinding media. A smaller size would result
in even smaller size of final product. Besides that, the hardness of
the grinding media, the stickiness of grinding media, the density of grinding
media also effect the process. Other equipment that can be used to reduce the
size particle is Hammer milling, fluid energy milling, and Colloid mill.
All of this equipment used the mechanism
of impact to reduce the size of particulate. In choosing the right equipment
for size reduction process, one of the factor influences is the nature of the
raw materials. Most of the raw material must be dried before undergo
the reduction process. Other than that, establishing the particle size required
are also important to avoid undesired particle size formed due to incorrect
choosing of right equipment. The product from the milling process is subjected
for particle size analysis
QUESTIONS:
1) What are the factors
that can influence the size reduction process of a ball mill?
- The number and size of the
steel balls used in the milling process.
- The speed of the ball milling
process.
2)What are the other
equipment that can be used in size reduction of solid materials?
- Hammer milling, fluid energy milling,
and colloid mill.
3)What are the factors
that need to be considered in choosing the suitable size reducing
equipment?
- The nature of the raw
materials.
CONCLUSION :
As the aim of this experiment is to study
the effect of the various parameters on the performance of a ball mill. The
factors studied are particle size,, time of grinding, and speed of the ball
mill (rpm). From the results, we can conclude that the amount of
fine particles increase with the increase in time of grinding, speed (rpm) of
the ball milling process.
REFERENCES:
A ball mill for all grinding and
milling needs. http://www.retsch.com/products/sumo/mixerball-millphp/ [24 November
2014]
Cao W. Synthesis of Nanomaterials by
High Energy Ball Milling. http://www.understandingnano.com/nanomaterial-synthesis-ball-milling.html
[25 November 2014]
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