The manufacture
of cement consists of grinding the raw materials (calcareous and argillaceous
stones consisting silica, alumina and iron oxide ) and mixing them intimately
in a certain proportion. it is then burnt in a large rotary kiln at
temeperature of 1500C, when the material sinters and partially fuses into balls
known as clinker. The clinker is cooled and ground to fine powder
with some gypsum added, and the resulting product is Commercial Portland
cement.
The main Components of Cement are
Lime - 63%
Silica - 22%
Alumina - 6%
Iron Oxide - 3%
Magnesium Oxide - 2.5%
Sulphur trioxide - 1.5%
Alkalies - 0.5%
The lime, silica and iron oxide imparts strength to cement ,
while alumina gives quick setting property. The alkalies when in excess, causes
efflorescence.
The Bougue's Components (Components of Cement Clinker)
Tri Calcium Silicate -C3S- 40%
Di Calcium Silicate - C2S- 32%
Tri Calcium Aluminate - C3A - 10.5%
Tetra Calcium Alumino Ferrite - C4AF- 9%
