Manufacturing Units – Aadi Cement

Cement Manufacturing Process

AADI Cement, a leading cement manufacturer in India, follows a highly efficient and sustainable process to produce high-quality cement. The company's manufacturing process is built around modern technology and a commitment to environmental sustainability.

1. Mining and Extraction of Raw Materials

Raw Materials:

AADI Cement primarily uses limestone, clay, and iron ore as its raw materials.
Limestone is the main source of calcium, while clay provides silica and alumina.
These raw materials are extracted from quarries or mines through controlled blasting and excavation techniques.

Quarry Management:

AADI Cement emphasizes sustainable mining practices, including the reclamation of mined land to ensure minimal environmental impact.

2. Crushing and Grinding of Raw Materials

Crushing:

The extracted raw materials (limestone, clay, etc.) are crushed in crushers to reduce their size.

Grinding:

The crushed materials are then finely ground in ball mills or vertical roller mills to produce a fine powder, called raw meal.
The crushed materials are then finely ground in ball mills or vertical roller mills to produce a fine powder, called raw meal.

3. Homogenization and Blending

Mixing:

The raw meal is mixed thoroughly to ensure a consistent chemical composition. This is done in blending silos or storage bins.

Homogenization:

The homogenization process ensures uniform distribution of key ingredients, especially when the raw materials are not naturally uniform in their composition. This step is critical for consistent cement quality.

4. Preheating and Calcination (Preheater/pre calciner)

Preheating:

The blended raw meal is fed into a preheater tower, where it is heated using hot gases from the kiln. This process removes moisture from the raw meal and prepares it for the next stage.

Calcination:

The preheated meal is then moved to a calciner, where it undergoes a chemical transformation.
Limestone (CaCO₃) decomposes into calcium oxide (CaO) and releases carbon dioxide (CO₂), creating lime (CaO), a key component in cement.

5. Clinker Formation in the Rotary Kiln

Rotary Kiln:

The calcined material enters the rotary kiln, where it is heated to 1450°C.
In the kiln, the raw materials undergo several complex chemical reactions that produce clinker—a solid, black, pebble-like substance that is the main component of cement.

Clinker Phases:

The rotary kiln is where the clinker forms, which consists of the four major phases of cement:
- Tricalcium silicate (C₃S)
- Dicalcium silicate (C₂S)
- Tricalcium aluminate (C₃A)
- Tetracalcium aluminoferrite (C₄AF)
The clinker production process is energy-intensive, so AADI Cement focuses on using alternative fuels (e.g., waste-derived fuels) to reduce its carbon footprint.

6. Cooling and Storage of Clinker

After being produced in the rotary kiln, the hot clinker is cooled in a clinker cooler.
The cooling process rapidly reduces the temperature of the clinker to around 100°C to 150°C.
The cooled clinker is then stored in clinker silos to maintain its quality and consistency before grinding.

7. Grinding and Blending of Cement

Grinding:

The cooled clinker is ground in ball mills or vertical roller mills along with a small amount of gypsum (usually 3–5%) to control the setting time.
Depending on the desired type of cement, blended materials like fly ash, slag, or lime may be added at this stage.

Blended Cement:

AADI produces a variety of cement, including Portland Pozzolana Cement (PPC) and Ordinary Portland Cement (OPC), by mixing clinker with supplementary materials such as fly ash or slag.

8. Packaging and Distribution

Once the cement is ground to the required fineness, it is stored in silos before being packed in bags or transported in bulk for distribution.
Automated packing machines ensure the accurate filling of cement bags, and the packed cement is then stored in warehouses before dispatch.

Raw Material Extraction

Materials: Limestone (primary raw material), clay, and other minerals. Extracted from mines or quarries.

Raw Material Preparation

Crushing: Limestone is crushed into smaller pieces.

Mixing & Grinding Crushed limestone is mixed with clay and ground into a fine powder called raw meal.

Preheating

The raw meal is preheated in a preheater tower to remove moisture and prepare it for the kiln.

Clinker Formation (Kiln Process)

The preheated raw meal is fed into a rotary kiln.

High Temperature : 1400–1450°C.

Chemical Reaction : Raw meal transforms into clinker (small, hard pellets) through a process called calcination.

Cooling

The hot clinker is cooled quickly in a cooler to retain its quality and prepare it for grinding.

Grinding & Mixing

Clinker is ground into a fine powder in ball mills.

Additives : Gypsum (to control setting time) and other materials (for specific cement types) are added.

The result is cement.

Packing & Distribution

The finished cement is packed in bags or bulk containers and transported to dealers or directly to construction sites.