Zeolites are primarily used as detergents (68%) and catalysts (8%). They are synthesized using a source of alumina and silica in the presence of a template at high pH. Analytical tools are used to characterize zeolites and ensure consistent quality between batches in terms of elemental composition, cation composition, bulk density, and thermal stability. Zeolites such as Zeolite A, X, and ZSM-5 are used in adsorption processes depending on their properties like SiO2/Al2O3 ratio and pore size.

1. 1
Synthesis and Applications of
Zeolites

2. 2
Detergents
68%
Catalysts
8%
Natural
zeolites
18%
Adsorbents
6%
Application fields and market
volume of zeolites

3. 3
Principle of zeolite synthesis
water
Source of alumina
Sodium aluminate
Aluminium sulfate
Aluminium oxide
Aluminium hydroxide
Source of silica
Sodium silicate
Precipitated silica
Silica gel
Silica sol
Flying ash
Template
Inorganic cation
Organic template
High pH
hydroxide
Zeolite
reaction

4. 4
Synthesis scheme
premix
reaction
filtration
Mother
liquor
dryer
Powder calciner
mixer
Granulation wheel
screen
screen
Fluidised bed calciner
packaging

5. 5
Analytical tools
• Elemental analysis
• Scanning electron microscopy (SEM)
• X-Ray diffraction
• Bulk density
• Dust formation
• Adsorption characteristics
• Grain size distribution
• Attrition
• Thermal and hydrothermal stability

6. 6
Elemental composition of
zeolites
1.95
2.00
2.05
2.10
1 2 3 4 5 6 7 8 9
batch number
SiO
2
/Al
2
O
3

7. 7
Cation composition of zeolites
90
95
100
105
110
1 2 3 4 5 6 7 8 9 10 11 12 13 14
batch number
cation
balance
(Na+K)/Al
(%)

8. 8
Bulk density of zeolites
720
730
740
750
760
2 4 6 8 10 12 14 16
batch number
bulk
density
(g/l)

9. 9
Dust measurement

10. 10
Principle of adsorption
measurement
cathetometer
Vacuum line
Pressure
control
permanent gases
condensable gases
sorbate
(temperature –80 to+20°C)
fused quartz
spring
sample
(temperature
–60 to+350°C)

11. 11
Particle size distribution
0
2
4
6
8
10
12
1.50 2.00 2.50 3.00 3.50
Bead size [mm]
Volume
[%]

12. 12
Thermal stability of zeolites
30
40
50
60
70
80
90
100
110
0 100 200 300 400 500 600 700
steaming temperature (°C)
original
water
adsorption
capacity
(%)
zeolite 3A zeolite 4A

13. 13
Principal adsorption process
inlet gas
adsorption desorption
separator condensator
heater
outlet gas

14. 14
Properties of zeolites used for
adsorption processes
• Zeolite A
– The most important zeolite for adsorption
processes
– SiO2/Al2O3 ratio of 2.0
– Adsorption of water

15. 15
Properties of zeolites used for
adsorption processes
• Zeolite X
– SiO2/Al2O3 ratio of 2.0–3.0
– Adsorption of gases at
low partial pressure

16. 16
Properties of zeolites used for
adsorption processes
• Zeolite ZSM-5
– SiO2/Al2O3 ratio of 20 - > 1000
– Hydrophobic zeolite
– Adsorption of organic
solvents

17. 17
Properties of zeolites used for
adsorption processes
• Ultrastable Zeolite Y
– Hydrophobic zeolite
– Large pore size
– Adsorption of organic
compounds

18. 18
Properties of zeolites used for
adsorption processes
• Adsorbents mainly used in agglomerated
form (extrudates or beads)
– High physical strength and attrition resistance
– Low dust formation tendency
– High macroporosity, high diffusion rate
– High hydrothermal stability
– High coking resistance

19. 19
Selected adsorption processes
• Natural gas drying and purification
Inlet gas
Adsorption Regeneration
Heater
Separator Condensator

20. 20
Selected adsorption processes
• Insulated glass windows
Molecular sieve
Window pane
Molecular sieve dust free
Molecular sieve adsorbs
water only
No oversized beads in
molecular sieve

21. 21
Selected adsorption processes
• Air prepurification
– Mainly NaX in use
– TSA and PSA process
• Air separation
– Mainly LiX and LiLSX in use
– Both PSA and VSA processes
– Up to 2.5 tonnes of oxygen per day and per
tonne of zeolite