This document provides an overview of the cement manufacturing process. It discusses the key raw materials used like limestone, clay, and iron oxide. The manufacturing process involves mixing and crushing raw materials, burning the mixture at high temperatures to form clinker, and grinding the clinker along with gypsum. The functions of various constituents in cement are also described. Finally, common applications and advantages/disadvantages of cement are summarized.

1. Chemical Process Industries II
Presented to: Dr. Haider Ali
Presented by: M. Usama Haroon
Rizwan Jamil
Ahmad Raza Ali

2. Contents
• Introduction
• Definition
• History
• Chemical Composition
• Classification
• Manufacturing Steps
• Functions of Cement Manufacturing Constituents
• Applications
• Advantages and Disadvantages

3. Introduction
• The word "cement" traces to the Romans, who used
the term opus caementicium to describe masonry
resembling modern concrete that was made from
crushed rock with burnt lime as binder.
• The volcanic ash and pulverized brick additives that
were added to the burnt lime to obtain a hydraulic
binder were later referred to as cement.

4. Definition
• Cement is the mixture of calcareous, siliceous,
argillaceous and other substances. Cement is used as
a binding material in mortar, concrete, etc.
• A substance that sets and hardens independently and
can bind other material together.

5. History
• First cements produced by early Greeks and Romans
from volcanic ash mixed with slaked lime.
• This art was lost during the Middle Ages.
• Portland cement developed in England by bricklayer
Joseph Aspdin in early 1800’s called “Portland”
because concrete made with it resembled natural
stone from the Isle of Portland.

6. Chemical Composition
• Lime 63 %
• Silica 22 %
• Alumina 06 %
• Iron oxide 03 %
• Gypsum 01 to 04 %

7. Classification
• Ordinary Portland Cement
• Sulphate Resisting Cement
• Rapid Hardening Cement (or) High Early Strength
cement
• Quick Setting Cement
• Low Heat Cement
• High Alumina Cement
• Air Entraining Cement
• White Cement

8. O.P.C
• It is the variety of artificial cement. It is called
Portland cement because on hardening (setting) its
color resembles to rocks near Portland in England. It
was first of all introduced in 1824 by Joseph Aspdin,
a bricklayer of Leeds, England.

9. Chemical Composition of
O.P.C
• Lime (CaO) 60 - 63 %
• Silica (SiO2) 17 - 25 %
• Alumina (Al2O3) 03 - 08 %
• Iron Oxide (Fe2O3) 0.5 - 6 %
• Magnesia (MgO) 1.5 - 3 %
• Sulphur tri oxide (SO3) 1 - 2 %
• Gypsum (CaSO4) 1 - 4 %

10. White Cement
• This cement is called snow Crete. As iron oxide gives
the grey color to cement, it is therefore necessary for
white cement to keep the content of iron oxide as low
as possible.
• Lime stone and china clay free from iron oxide are
suitable for its manufacturing. This cement is costlier
than O.P.C. It is mainly used for architectural
finishing in the buildings

11. Manufacturing Steps
• Mixing and Crushing of Raw Materials
a) Wet Process
b) Dry Process
• Burning or Calcination
• Grinding

12. Cement Manufacturing

13. Mixing Process
Wet process
• Calcareous materials are crushed, powdered and stored in bins.
• Argillaceous materials is mixed with water and washed. This removes any
adhering organic impurities.
• Powdered Calcareous and Washed Argillaceous materials are mixed in
proper proportions to get a slurry.
• Chemical composition is analyzed and corrected if necessary by addition
of the deficient materials.
• This slurry is then fed into the rotary kiln.
Dry process
• Hard raw materials like cement rock or blast furnace slag are first crushed
to 50mm pieces in ball mill, then dried and stored.
• Crushing is done by gyratory crushers and drying is done by rotary driers.
• Separate powdered ingredients are mixed in required proportions to get the
raw mix which is then fed to rotary kilns.

14. Burning / Calcination
• Corrected slurry is feed to rotary kiln, which is a 150-
500 feet long, 8-16 feet in diameter and temperature
arrangement is up to 1500- 1650°C . At this
temperature slurry losses moisture and forms into
small lumps, after that changes to clinkers. Clinkers
are cooled in another inclined tube similar to kiln but
of lesser length

15. Grinding
• Now the final process is applied which is grinding of
clinker, it is first cooled down to atmospheric
temperature. Grinding of clinker is done in large tube
mills. After proper grinding gypsum (Calcium
sulphate CaSO4) in the ratio of 01-04 % is added for
controlling the setting time of cement. Finally, fine
ground cement is stored in storage tanks from where
it is drawn for packing.

16. Process Flow Diagram

17. Functions of
Cement
Manufacturing
Constituents

18. Lime (CaO)
• Lime forms nearly two-third (2/3) of the cement.
Therefore sufficient quantity of the lime must be in
the raw materials for the manufacturing of cement. Its
proportion has an important effect on the cement.
Sufficient quantity of lime forms di-calcium silicate
(CaSiO2) and tri-calcium silicate in the
manufacturing of cement.
• Lime in excess, causes the cement to expand and
disintegrate.

19. Silica (SiO2)
• The quantity of silica should be enough to form di-
calcium silicate (C2SiO2) and tri-calcium silicate in
the manufacturing of cement. Silica gives
strength to the cement. Silica in excess causes the
cement to set slowly

20. Alumina (Al2O3)
• Alumina supports to set quickly to the cement. It also
lowers the clinkering temperature. Alumina in excess,
reduces the strength of the cement.

21. Iron Oxide (Fe2O3)
• Iron oxide gives color to the cement

22. Magnesia (MgO)
• It also helps in giving color to the cement.
Magnesium in excess makes the cement
unsound

23. Gypsum (CaSO4)
• At the final stage of manufacturing, gypsum is added
to increase the setting of cement.

24. Applications
• Building
(floors, beams, columns, roofing, piles, bricks, mortar, panels,
plaster).
• Transport
(roads, pathways, crossings, bridges, sleepers, viaducts, tunnels,
stabilization, runways, parking).
• Water
(pipes, culverts, kerbing, drains, canals, weirs, dams, tanks,
pools).
• Civil
(piers, docks, retaining walls, silos, warehousing, poles, pylons,
fencing)

25. Advantages and Disadvantages
• Advantages:
Cement is very strong.
It can create large structures quickly.
It conforms to different shapes (arcs and circles, etc.)
It has high thermal mass (moderates temperature).
• Disadvantages:
Cement is subjected to cracking.
It is very difficult to provide idoneous curing conditions.
It is not ideal for situation when settlement is expected.