Transcript Top-down approach 長庚化材系 郭修伯 Grinding  粗碎：    m 級 to 10 cm 以下 Jaw crusher Gyratory crusher.

Top-down approach
長庚化材系
郭修伯
Grinding
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粗碎：
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m 級 to 10 cm 以下
Jaw crusher
Gyratory crusher
Grinding
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中碎：
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10 cm to 1 cm 以下; Crushing roll
Grinding
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中碎：
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10 cm to 1 cm 以下; Hammer mill & Roller mill
Grinding
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微粉碎：
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1 cm to 10 micron 以下; roller mill, jet mill, ball mill,
vibration mill, planetary mill
Low temperature increasing
32
N
(
rpm
)

大小ball分佈；最適回轉數
D(m)
Grinding
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微粉碎：
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1 cm to 10 micron 以下; roller mill, jet mill, ball mill,
vibration mill, planetary mill
40-50 % fill, several g
Grinding
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超微粉碎：
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10 micron to 1 micron 以下; 介質攪拌型粉碎機, vibration
mill, planetary mill
Surface charge distribution
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The distributions of ions and counter
ions are controlled by
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Coulomic force or electrostatic force
Entropic force or dispersion
Brownian motion
Inhomogenous distribution
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double layer structure
separated by the Helmholtz plane
Fig 2.14
Van der Waals attraction potential
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The sum of the molecular interaction for
all pairs of molecules
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weak force and becomes significant only at
a very short distance
agglomeration of nanoparticles: the
combination of van der Waals force and
Brownian motion
Prevent agglomeration: electrostatic
repulsion and steric exclusion
Electrostatic repulsion stabilization
Fig 2.18
Steric exclusion stabilization
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Also “polymeric stabilization”
Widely used in stabilization of colloidal
dispersions
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thermodynamic stabilization: particles are
always redispersible
high concentration can be accommodated
not electrolyte sensitive
suitable to multiple phase systems
Polymeric stabilization
Fig 2.21
Gas phase particle formation
Gas phase particle formation, CVD
Gas phase particle formation, CVD
Gas phase particle formation, CVD
Formation of particles in solutions
Formation of particles in solutions
Formation of particles in solutions,
chemical methods
Formation of particles in solutions,
physical methods