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1. Cement Manufacturing
(Alan Gee-Lehigh Hanson Cement)

2. Joseph Aspdin
Patented Portland Cement
in 1824

3. 3
Dual Line Preheater

4. 4
Planetary Cooler

6. 6
View of Tower System

7. What we will discuss
• Cement making process
– Raw materials, clinker, cement
• Cement Chemist’ Language

8. CEMENT NOTATION
• IS A SHORT HAND WAY TO GIVE THE PHASE
COMPOSITION OF A CEMENT
• IS BASED ON MODEL COMPOUNDS
ACTUAL CEMENT PHASES ARE MORE OR LESS CLOSE
TO THIS IDEAL VIEW

9. CEMENT INDUSTRY SYMBOLS
Name of substance Chemical
symbol
Cement
industry
symbol
Molar
mass
Calcium oxide or lime CaO C 56
Silica SiO2 S 60
Alumina Al2O3 A 106
Iron oxide Fe2O3 F 160

10. TYPICAL COMPOUND COMPOSITION OF ORDINARY PORTLAND CEMENT
CHEMICAL NAME CHEMICAL CEMENT WEIGHT
FORMULA NOTATIONa (%)
Tricalcium silicate 3CaO•SiO2 C3S 50
Dicalcium silicate 2CaO•SiO2 C2S 25
Tricalcium aluminate 3CaO•Al2O3 C3A 12
Tetracalcium aluminoferrite 4CaO•Al2O3•Fe2O3 C4AF 8
Calcium sulfate dihydrate CaSO4•2H2O CSH2 3.5
(gypsum)
a C = CaO, S = SiO2, A = Al2O3, F = Fe2O3, S = SO3, H = H2O

11. Cement Manufacturing Process

12. Cement Manufacturing Process

13. Cement Manufacturing Process

14. CaO SiO2 Al2O3 Fe2O3 MgO Loss
Limestone (chalk) 52.0 5.7 0.8 0.3 0.4 40.4
High-silica limestone 33.6 36.8 1.8 0.6 0.5 26.4
Cement rock 40.0 18.0 5.0 1.5 2.0 32.0
Blast-furnace slag 35.5 33.1 9.1 0.9 16.4 2.1
Shale 3.2 53.8 18.9 7.7 2.2 13.1
Sand 0.8 70.0 15.0 5.0 0.2 8.6
Clay 0.5 61.0 16.9 12.4 0.4 7.8
Iron ore - 6.7 1.4 89.7 0.4 0.2
Steel-mill scale - 2.5 1.1 89.9 - 4.0
TYPICAL COMPOSITION OF RAW MATERIALS

15. Kiln Process Thermochemical Reactions
Process Reactions Temperature ºC
free water evaporates 20 - 100
Drying/
Pre-heat
crystallization water
driven out
100-300
chemical water driven
out
400 - 900
calcining CO2 Driven out
CaCO3 --> CaO+CO2
600 - 900
sintering
clinkering
Formation of Liquid
Phase,
Formation of alite and
belite
1450 exothermic
cooling Crystallization of
aluminates and ferrites
1300 - 1240
Kiln Process
English Units
68 – 212 deg F
212 -572 deg F
752 -1652 deg F
1112-1652 deg F
2642 deg F
(2440-2642 degF)
2264 -2372 deg F
Carbon Steel Temp – 800 deg F, Refractory needed after that.

17. Generalized Diagram of a Long Dry Process Kiln
Burner
Kiln hood
Clinker cooler
Clinker
Exit gases
Kiln feed
Dehydration
zone
Calcination
zone
Clinkering
zone
Cooling
zone
Gas Temp
Mat’l temp
450°C
840°F
800°C
1470°F
1200°C
2190°F
1500°C
2730°F
1750°C
3180°F
50°C
120°F
600°C
1110°F
1000°C
1830°F
1350°C
2460°F
1450°C
2640°F
Free
water
Clay
decomposition
Limestone
decomposition
Formation
of initial
compounds
Initial
formation
of C2S
Formation
of melt
Formation
of C3S
Burner
Kiln hood
Clinker cooler
Clinker
Exit gases
Kiln feed
Dehydration
zone
Calcination
zone
Clinkering
zone
Cooling
zone
Gas Temp
Mat’l temp
450°C
840°F
800°C
1470°F
1200°C
2190°F
1500°C
2730°F
1750°C
3180°F
50°C
120°F
600°C
1110°F
1000°C
1830°F
1350°C
2460°F
1450°C
2640°F
Free
water
Clay
decomposition
Limestone
decomposition
Formation
of initial
compounds
Initial
formation
of C2S
Formation
of melt
Formation
of C3S
The kiln exit gas temperature
will depend on the process.

18. Sintering
Cooling
Calcining
Drying
Preheating
Precalcining
Gas Material
General Diagram of Preheater Reactions
In the tower,
Preheaters do 40-80% calcination.
Precalciners do 70 to 96% calcination.
The difference is the no. of stages, type of calciner,
and often the available length of kiln.

19. Cement
• Cement = Clinker+sulfate+water+processing
addition+limestone
– Controlled fineness, chemistry

20. Questions?