A rotary kiln is a large, rotating cylindrical furnace used in various industrial processes to heat materials to high temperatures (typically between 900°C and 1,500°C or higher). It is widely used in industries like cement production, métallurgie, traitement chimique, and waste treatment.

Key Components of a Rotary Kiln:
1. Cylinder (Coquille): A long, slightly inclined steel tube lined with refractory bricks to withstand high temperatures.
2. Système d'entraînement: Motors and gears that rotate the kiln at a controlled speed (typically 0.5–5 RPM).
3. Support Rollers & Tyres (Riding Rings): Bearings that support the kiln's weight and allow smooth rotation.
4. Burner & Fuel System: Provides heat using fuels like coal, gaz, huile, or alternative fuels (par ex., waste materials).
5. Revêtement réfractaire: Heat-resistant material inside the kiln to protect the shell and retain heat.
6. Scellés: Prevent air leakage at the inlet and outlet.
7. Refroidissement & Exhaust Systems: Manage temperature and emissions.

How a Rotary Kiln Works:
1. Material Feed: Raw materials (par ex., calcaire, minerai, or waste) enter the kiln’s upper end.
2. Rotation & Heating: The inclined kiln rotates slowly, causing material to move toward the hotter end while being heated by the burner.
3. Chemical Reactions: High temperatures trigger processes like calcination (par ex., turning limestone into lime), réduction (métaux), or clinker formation (ciment).
4.

charge: Processed material exits at the lower end for cooling/further processing.

Applications of Rotary Kilns:
1. Production de ciment:
- Calcination of limestone to produce clinker (main component of Portland cement).
2. Métallurgie:
- Roasting/refining ores (par ex., fer, aluminium, zinc).
- Production of sponge iron via direct reduction (DRI).
3. Industrie chimique:
- Manufacturing lime, alumine, titanium dioxide, etc..
4. Waste Treatment:
- Incineration of hazardous waste or sewage sludge.
- Pyrolysis of tires/plastics for recycling.

Avantages:
✔ Continuous processing with high throughput.