Comminution

Question 1

Particle size influences bioavailability - a smaller particle size results in faster dissolution. True or false?

Answer 1

True

Question 2

What is meant by comminution?

Answer 2

The reduction of solid materials from a bigger mean particle size to a smaller mean particle size

Question 3

The efficiency of a conventional ball mill is greater than that of a vibratory mill. True or false?

Answer 3

False - vibratory mill more efficient

Question 4

Dry sieving is usually more efficient than wet sieving. True or false?

Answer 4

False - wet sieving is more efficient

Question 5

Which milling method is defined as self-classifying?

Answer 5

Cutter mill

Question 6

Separation efficiency is the effectiveness of a given process in separating particles into oversized and undersized fractions. True or false?

Answer 6

True

Question 7

How many micrometres is a coarse powder?

Answer 7

> 350

Question 8

How many micrometres is a medium/fine powder?

Answer 8

100-350

Question 9

How many micrometres is a fine powder?

Answer 9

50-100

Question 10

How many micrometres is a very fine powder?

Answer 10

10-50

Question 11

How many micrometres is a micronised powder?

Answer 11

<10

Question 12

The sieve method is simpler and more cost effective than microscopy. True or false?

Answer 12

True

Question 13

The sieve method provides particle shape information. True or false?

Answer 13

False

Question 14

Which particle size analysis method sorts a large quantity of particles into different size ranges and determines the particle size distribution based on the mass collected in each range?

Answer 14

Sieve method

Question 15

Mohs’ scale is a quantitative measure of hardness. True or false?

Answer 15

False - qualitative

Question 16

Brinell or vickers is a quantitative measure of hardness true or false?

Answer 16

True

Question 17

Which milling method achieves a particles size of 1-300 micrometres?

Answer 17

Attrition

Question 18

Which milling method achieves a particles size of 100-100,000 micrometres?

Answer 18

Cutting

Question 19

What particle size can a ball mill achieve?

Answer 19

1-200 micrometres

Question 20

Which milling method achieves a particles size of 20-100,00 mircometres?

Answer 20

End runner

Question 21

Which milling method achieves a particle size of 1-1000 micrometres?

Answer 21

Vibration

Question 22

Which milling method achieves a particle size of 600-200,000 micrometres?

Answer 22

Roller

Question 23

What particle size can a fluid energy mill achieve?

Answer 23

1-100,000 micrometres

Question 24

Which milling method achieves a particle size of 10-9,000 micrometres?

Answer 24

Pin mill

Question 25

What particle size does a hammer mill achieve?

Answer 25

30 - 10,000 micrometres