Cement Procedure
#CementProcedure
The cement manufacturing procedure involves a series of steps that transform raw materials like limestone into the finished product — Portland cement, the most common type used in construction.
Here’s a clear and concise breakdown:
Cement Manufacturing Process
1. Raw Material Extraction
• Main materials:
• Limestone (CaCO₃) – provides calcium
• Clay/shale – provides silica (SiO₂), alumina (Al₂O₃), and iron oxide (Fe₂O₃)
• Mining: Materials are extracted from quarries using blasting or cutting.
2. Crushing and Pre-homogenization
Step 1: Large rocks crushed to smaller pieces.
Step 2: Materials mixed and homogenized to ensure chemical consistency.
3. Raw Meal Grinding
Crushed materials are finely ground in a ball mill or vertical roller mill to produce raw meal (fine powder).
4. Preheating and Calcination
Raw meal enters a preheater tower (series of cyclone stages).
• Calcination (~850–900°C):
• CaCO₃ CaO (lime) + CO₂
• This is the first major chemical reaction.
5. Clinker Formation (Kiln Phase)
• Heated to ~1450°C in a rotary kiln.
• Forms clinker nodules – small, grayish pellets containing:
• Alite (C₃S) – strength-giving compound
• Belite (C₂S), Tricalcium aluminate (C₃A), Tetracalcium aluminoferrite (C₄AF)
#Clinker
6. Clinker Cooling
Rapid cooling in air quench coolers to stabilize compounds.
Waste heat is often recycled for efficiency.
7. Grinding with Additives
Clinker mixed with:
Gypsum (CaSO₄·2H₂O) – controls setting time
Optional materials: fly ash, slag, limestone (for blended cements)
Ground to fine powder Portland cement
8. Storage and Packaging
• Cement stored in silos.
• Packed in bags or loaded in bulk into trucks for transport.
Summary Flowchart
Limestone + Clay
Crushing
Raw Meal Grinding
Preheating Calcination (CO₂ released)
Rotary Kiln (Clinker Formation)
Clinker Cooling
Grinding + Gypsum Cement
Packaging/Shipping
Chemical Summary (Key Reaction)
CaCO₃ (limestone) CaO (lime) + CO₂
Then:
CaO + SiO₂ Ca₂SiO₄ (Belite)
CaO + SiO₂ Ca₃SiO₅ (Alite)
These compounds give cement its strength.
Environmental Notes
Cement manufacturing is CO₂-intensive, especially from:
• Calcination (chemical CO₂ release)
• Fuel combustion
• Green technologies:
• Alternative fuels (RDF, biomass)
• Carbon capture
• Blended cements (fly ash, slag)
• A diagram of the process
• Detailed chemical equations
• Focus on green cement technologies
Comparison: wet vs dry process (modern cement mostly uses the dry method)
