Lab Report 1 and 2: PRACTICAL 1 : BALL MILLING

AIMS:

1. To grind the given material to a smaller size using a ball mill
2. To obtain the size distribution of the initial and the final mixture by sieving.
3. To analyze the results using the available theories.

INTRODUCTION:

Ball Mill is the equipment to be used for size reduction. It is a kind of grinder used for intermediate or fine grinding. Ball mill is a metal cylinder which rotates about its horizontal axis. The coarse sugar charged along with the metal balls breaks to fine powder by impact of metal balls. The size reduction is actually to make the too large to be used solid materials usable. It leads to an increase in surface area per unit volume that enhances the rate of the reaction by allowing more sites for the reaction to take place. Moreover handling of smaller size particles is much easier as compared to that of bigger particles.

APPARATUS AND MATERIALS:

Metal balls (various sizes), coarse sugar, rotary milling, sieve nest.

PROCEDURE:

1. 300-500g of coarse sugar was weighed.
2. The various sizes of metal balls were put into the mill.
3. The coarse sugar was added into the mill.
4. The milling process was started for 15-20 minutes with the appropriate speed.
5. The product was weighed again.
6.The powder then was sieved using sieve nest.
7. A graph of distribution size particle was plotted.

RESULTS AND CALCULATION:

Results and Calculation :

Group	Duration of ball Milling	Speed(ms^-1)	Size Of (g)	Grinded	Salt
	(min)		150um	250um	300um
1 and 2	10	5	5.0079	3.6538	12.0589
3 and 4	20	5	2.8825	0.1794	20.2832
5 and 6	10	3	0.2967	1.3826	12.0507
7 and 8	20	3	0.4682	0.8602	11.1693

Group 1 and 2: ( Set 1)

Group 3 and 4: ( Set 2)

Group 5 and 6: (Set 3)

Group 7 and 8: (Set 4)

CALCULATION :

Weight of grinded salt that is in the range of 150um-300um

Set 1:

5.0079g+3.6583g+12.0589g=20.7206g

Set 2:

2.8825g+0.1794g+20.2832g=23.3451g

Set 3:

0.2967g+1.3862g+12.0507g=13.7336g

Set 4:

0.4682g+0.8602g+11.1693g=12.4977g

DISCUSSION:

Based on the results we obtained, set 1 (10 min, speed 5), the amount of weight of grinded salt that is in the range of 150um-300um is 20.7206 g. Meanwhile, set 2 (20 min, speed 5) is 23.3451 g. This means that set 2 has higher amout of weight of grinded salt that is in the range of 150um-300um. This is because set 2 has longer duration which is 10 minutes longer than set 1 while maintaining the same speed 5. This causes more smaller size salt to be produced.

After that, the amount of weight of grinded salt that is in the range of 150um-300um for set 3 (10 min, speed 3) is 13.7336 g. Meanwhile for set 4 (20 min, speed 3) is 12.4977 g. Based on the same reason, that is the set 4 has longer duration than set 3 with same speed 3, should be set 4 has higher amount of weight of grinded salt that is in the range of 150um-300um. However, in this experiment, set 3 has higher value than set 4. This is due to some errors that have occurred while carrying out the experiment. The error might be the spilling out of the powders during transmission to the sieving part. And as well as the different strength of people used while sieving.

Apart from comparing the duration of the sets, the comparison of the results can also be seen by comparing the speed of the sets. For example, set 1(10min, speed 5) is more (20.7206g) compared to set 3 (10min, speed 3) which is 13.7336g. The weight of the salt produced in the stated range from set 2 (20min, speed 5) is more (23.3451g) compared to set 4 (20min, speed 3) which is 12.4977g. This means that the faster the speed, the more product is produced in desired range.

QUESTIONS:

CONCLUSION:

As a conclusion, the higher the speed of the sets, the higher the products amount produced in desired size range. The high amount of products produced can also be because of the longer duration of the sets in ball milling process. However, the speed has more effects on products produced compared to duration of the sets in this experiment.

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