THE 12 STAGES OF MANUFACTURE
Phases of the typical cement production process
1. Exploitation of the quarry
By means of small controlled detonations, the limestone is extracted, main raw material of the process.
The limestone is crushed in successive phases until it reaches fragments of about 50 mm.
3. Transport of raw materials
The materials are transported through covered conveyor belts to minimize dust and contaminants emissions.
Starting from the variable qualities of the stone, a uniform mineral composition is obtained, the raw mix.
5. Storage and grinding of raw meal
With mills of bars or steel balls the ideal granulometry is obtained to form the raw meal.
Raw meal passes through the pre-calcination cyclone exchanger, where the residual heat of the furnace gases is used.
7. Rotary kiln: calcination and cooling
Raw meal is the subject of a series of physical and chemical transformations that take place in large rotary kilns:
• up to 500ºC, dehydration of the clay;
• between 550 ° C and 1,100 °C, decarbonation;
• between 1,300 ºC and 1,500 °C, clinkerization.
The clinker passes from approximately 1,450 °C to approximately 140 °C through refrigeration grids or satellite tubes attached to the kiln, from which the released gases are sent to point 6.
8. Clinker storage
9. Clinker grinding and cement manufacturing
Once the additions, gypsum and other additives have been dosed, the materials are milled and homogenized until the final product is obtained: Portland cement.
10. Cement Storage
11. Packaging or bulk shipment
12. Sale and transportation