Particle size analysis

Question 1

Particle size analysis techniques

Answer 1

Sieving/ Microscopy/ Sedimentation/ Coulter counter/ laser light scattering

Question 2

Air jet sieving

Answer 2

Individual sieve starts with the finest aperture sieve, particle vacuum collects small particles through mesh and the reverse air jet prevents blocking.

Question 3

Wet sieving and disadvantage

Answer 3

Material is passed through the sieve by fluid flow rather then gravity and vibration

• no 3D info
• low throughput
• high operative fatigue

Question 4

TEM/SEM (transmission / scanning electron microscope)

Answer 4

Particles are individually examined

• Shape can be measured
• 3D
• Expensive
• Time consuming sample prep
• Increase depth compared to light microscope

Question 5

Andersons pipette

Answer 5

1) Suspend liquid
2) Add dispensing agent to prevent aggregation
3) Fill pipette with homogeneous liquid
4) Remove sample at set time intervals
5) Determine weight by
- Gravimetric analysis
- Chemical analysis
6) Calculate radius using Stoke’s law

Question 6

Sedimentation (Andersons pipette)

Answer 6

1) Suspend liquid
2) Add dispensing agent - prevents aggregation
3) Fill pipette with homogeneous liquid
4) Remove sample at set time intervals
5) Determine weight by
- Gravimetric analysis
- Chemical analysis
6) Calculate radius using Stoke’s law

Question 7

Counter method

Answer 7

Particles flow through aperture and displace electrons equivalent to their volume.

Causing electrical change which is proportional to the volume of particles, used for counting RBC

Question 8

Aerodynamic Impaction

Answer 8

The diameter of the sphere of density with the same setting velocity as a particle of interest.
Gravimetric or chemical analysis of material at each stage

Question 9

Microscopy

Answer 9

Each field can be examined and distribution can be obtained

• Coupled to image analysis computer
• Small particles diffraction effect increases including blurring at the edge of determination of particles

Question 10

Laser diffraction analysis

Answer 10

Uses a laser light sauce, interaction with particle caus light to be scattered in a forward direction with a small change in angle.

Produces light intensity patters that occur at regular angular intervals and are proportional to the particle diameter producing scatter

Question 11

Laser diffraction analysis

Answer 11

Uses a laser light sauce, interaction with particle can caus light to be scattered in a forward direction with a small change in angle.

Produces light intensity patterns that occur at regular angular intervals and are proportional to the particle diameter producing scatter

Question 12

Martins diameter

Answer 12

Length of the line which bisects the image of the particle

Question 13

Fretes diameter

Answer 13

Distance between two tangents on opposite side of particle and parallel to some fixed position.

Question 14

Project area diameter

Answer 14

Diameter of the circle having the same area as the particle viewed normally to a plane surface on which the particle is at rest in a stable position.