Back to AI Flashcard MakerMedicine /Pharm Y2S2 - Comminution
Define comminution.
Reduction of solid particles to lower average particle size
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/32
Key Terms
Term
Definition
Define comminution.
Reduction of solid particles to lower average particle size
What size classification are granules?
Up to 2mm
What size classification is a coarse powder?
> 350um
What size classification is a medium/fine powder?
100-350um
What size classification is a fine powder?
50-100um
What size classification is a very fine powder?
10-50um
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Define comminution. | Reduction of solid particles to lower average particle size |
What size classification are granules? | Up to 2mm |
What size classification is a coarse powder? | > 350um |
What size classification is a medium/fine powder? | 100-350um |
What size classification is a fine powder? | 50-100um |
What size classification is a very fine powder? | 10-50um |
What size classification is a micronised powder? | <10um |
What is a disadvantage of using a sieve for particle size analysis? | Limited information about shape or size range |
What is a disadvantage of using microscopy for particle size analysis? | Not representative |
What is a disadvantage of using laser diffraction for particle size analysis? | Must consider interaction with the solvent Particles assumed to be spheres |
Define milling. | Transformation of approximate normal particle size distribution into a finer bimodal population |
What effect does prolonged milling have? | Forms a unimodal population |
What happens when particle sizes are reduced to 1-5um? | Particle-particle forces predominate and agglomeration can occur |
What are the features of cutting methods? | Series of knives/blades on rotor High shear rates Screen acts to retain particles larger than a specified size |
What are the features of compression methods? | Material passes through rollers, one is mechanically driven Series of rollers can be used to achieve smaller particles |
What are the features of impact methods? | Filled to 80% with steel balls Body of the mill vibrates |
Give examples of size separation methods. | Sieving Sedimentation Cyclone Elutriation |
Give examples of agitation methods. | Oscillation Mechanical vibratioon Gyration |
What is crack propagation? | Localised stress producing strains in particles that lead to ruptures/cracking |
At low temperatures, what happens to materials? | Transition from plastic to brittle behaviours |
How is energy lost? | Elastic/plastic deformation Deformation initiating cracks Interaction with mechanics Heat Vibration |
What is the Moh’s scale? | Qualitative determination of hardness |
What methods can be used to determine hardness qualitatively? | Brinell and Vickers |
What is the range of attrition? | 1-100um |
What is the range of hammer milling? | 30-10000um |
What is the range of vibration milling? | 1-1000um |
What is the range of roller milling? | 600-200000um |
What is the range of end runner milling? | 20-100000um |
What is the range of cutting? | 100-100000um |
What is the range of fluid energy milling? | 1-100000um |
What is the range of pin milling? | 10-9000um |
What is the range of ball milling? | 1-200um |