Definition: the effectiveness of a given process in
separation particles into oversize and undersize fraction
Objective of size
separation:
1. Powder particles are removed from gases or liquid
2. To prevent environmental pollution
3. Classify powders
into separated particle size ranges
Size
separation efficiency:
The efficiency of
powder which separated into
different particle size ranges is related to the
particle, fluid properties and separation method used.
Size separation
methods
1. Size separation
by sieving:
• Separation ranges 5-10000
•Principle
of operation: the wire mesh used of British standard sieves should be of
uniform circular cross-section & adequate strength to avoid any chemical
action of the material to be sifted.
Mechanical disturbances of the
powder •
1. Agitation methods
2. Brushing methods
3. Centrifugal methods
2. Size separation by fluid:
a. Sedimentation methods (The
fluid is stationary & the separation depends on particle velocity)
Centrifugal Gravitational
Sedimentation Sedimentation
(0.1-4
) (4-1000
)
b. Elutriation methods (The
fluid flows in an opposite direction to the Sedimentation movement)
Centrifugal Gravitational
Elutriation Elutriation
(0.5-40
) (10-500
)
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