Question

71) How is cement manufactured? Mention the areas of application of cement.

Answer 1

Part I - Manufacturing Process

The raw material used for manufacturing Portland cement is limestone and clay. Two different processes are involved in the formation of cement

• Dry Process - A mixture of limestone and clay is subjected to making powder into a pulverizer, which is then heated to $1500°\mathrm{C}-1600°\mathrm{C}$ , which leads to the formation of hard nodules of mixed powder. These hard nodules are again subjected to pulverization ( formation of powder) and then gypsum is added to form cement.
• Wet Process - Here water is added to the pulverized mixture and the slurry obtained after it is subjected to heat to form hard nodules of the mixture.

Part II - Areas of application

• Cement mortar - It is prepared by mixing cement and sand in a ratio of 1:4 by weight. It is a construction related material which when added with water forms a slurry and is used in joining the bricks and plastering.
• Concrete - It is made up of mixture of cement, gravel, and sand in the ratio of 1:2:3, and then water is added to it so as to form a hard mixture which is used in construction of roofs etc.
• Grouting - Grouting is a technique used in construction activities. In this, a mixture of Cement and water is used in filling the gaps between bricks in construction activities.