Manufacturing Process of Cement:

The subsequent raw materials are commonly needed for manufacturing of cement:

Calcareous Materials

The materials which contain calcium or lime as their major constituent are known as calcareous materials. The several calcareous materials used in the manufacture of cement are lime stone, marl, chalk, shells, etc. These materials provide the required proportion of lime to the cement.

Argillaceous Materials

The argillaceous materials contain alumina as their major constituent. The various argillaceous materials used in the manufacture of cement are shale, clay, laterite, etc. These materials provide the required proportion of silica, alumina, oxide of iron, etc. to the cement.

The process of manufacture of cement consists of grinding the raw materials (calcareous and argillaceous materials) mixing them intimately in certain proportions and burning them in a kiln at a temperature of about 1500°C at which the material sinters and fuses to form nodular shaped clinker. The clinker is cooled and ground to a fine powder with addition of about 2 to 3 % of gypsum. The product obtained by this procedure is called as Portland Cement. There are two procedures called as Wet and Dry processes depending upon whether the mixing and grinding of raw materials is done in wet or dry condition. The wet process requires more fuel as slurry contains about 35-50 % water. The dry process requires less fuel as materials are already in dry state.