Steps to making Portland cement
- 1. Quarrying the raw materials: At quarries, limestone is blasted from the earth with the help of explosives. The limestone is then brought out of the quarry.
- 2. Crushing the minerals: Machines crush the limestone into small pieces.
- 3. Mixing the minerals together: The crushed limestone is mixed with clay or sand until it becomes a uniform mixture. The clay and sand are sources of silicon and the limestone is a source of calcium.
- 4. Heating the mixture: The limestone and clay mixture is heated in a kiln to a very high temperature.
- 5. Clinker: After the minerals are heated, they bond with each other in a substance known as Clinker. Clinker is very dry and porous.
- 6. Grinding it: The clinker is ground to a powder with gypsum, which is a soft mineral.
- 7. Adding water: When water is added to the mixture, it creates a paste that helps rocks and sand stick together in concrete.
