Name 4 methods of physical enrichment.
Sedimentation
foaming
magnetic seperation
dielectric speration
Name 4 types of clays and their composition.
kaolin= kaolinite
ball clay= carbonates+ caolinite
fire clay= kaolinite + quartz
common clay= carbonates + silicates + kaolinite
Describe the bayer process for alumina.
Enrichment of milled bauxite with NaOH (150-160°C, 5 bar)
filtering out the undissolved impurities
preciptation (Al(OH)3 solidifies and Na is washed out
calcination (removal of OH) at 1100-1200°C -> Al2O3
milling
Describe the plasma route for zirkonia.
ZrSiO4 molten by plasma at 6000°C
decomposition into ZrO2 and SiO2
ZrO2 solidifies faster and is removed
Which forms of forceinjection are there in milling?
compression
impact
shear
Name two shear mills
vibration mill
ball mill
How is the energy for milling calculated?
Ac=mill factor
m=material coefficient
Why is there an optimal milling time?
because the particle size converges against a limit with infinite time.
Name the components.
Name 3 particle size analysis methods
sieving
weighting after each step to get mass percentage
measuring of the time of sedimentation, which is related to the size
laser diffraction
angle of diffraction related to diameter
How is the Specific Surface area related to the particle diameter?
how is the apparent specific volume calculated?
How is the optimal packing factor calculated for two particles in mixture?
PF=PFc+(1-PFc)PFf
c=coarse
f=fine
What is the role of surfactants?
They combine hydrophilic and hydrophobic materials.
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