Granulation Flashcards
What is granulation?
Aggregates of particles
What are some pros of granulation?
Better handling Less likely to separate Better compaction characteristics Reduced fines Higher bulk density
What are the cons of granulation (2)?
Additional processing steps
Instability during granulation
What does particle aggregation result in?
Particle size enlargement
What does granulation require?
Powder ingredients
Binder
Granulation equipment
What are the two types of granulation?
Wet
Dry
What ways can you make wet granulation?
Shear
Fluidised bed mixer
What ways can you make dry granulates?
Slugging
Roller
What is the granulation process?
1) mix powder ingredients
2) Aggregate powders using a suitable binder
Wet: solution binder
Dry: solid binder
3) Dry granules (wet granulation)
4) Sieve granules to select particle size
What is a binder?
“inter-particle glue”
What are used as wet granulation polymers usually?
Amorphous polymers
What are the 3 processes of wet granulation?
1) wetting and nucleation
2) Consolidation and coalescence
3) Attrition and breakage
What happens in the wetting and nucleation step?
Particles are wetted/infiltrated by binder solution - nuclei formed
Uniform wetting
What are the important parameters in wetting and nucleation? (3)
Droplet size
Particle wetting propertied
Particle flux in wetting zone
What happens in consolidation and coalescence?
Particles collide with nuclei, deform and adhere
