Working Principle
The activated carbon making machine (typically a rotary kiln) operates on the principle of thermal treatment to convert carbonaceous materials into activated carbon through two main stages:
1. Carbonization Stage
Raw materials (such as coconut shells, wood, coal, or bamboo) are heated in an oxygen-limited or oxygen-free environment
Temperatures typically range from 400°C to 600°C
Volatile components (gases, tars, and other non-carbon elements) are driven off
A preliminary carbon structure (char) is formed
2. Activation Stage
The carbonized material is exposed to oxidizing gases (steam, carbon dioxide, or air) at higher temperatures (800°C to 1,000°C)
The oxidizing agents react with the carbon to create a highly porous structure
This process develops an extensive network of micropores, mesopores, and macropores
The result is a material with extremely high surface area (typically 500–1,500 m²/g)
Key operational features of a rotary kiln:
The kiln body rotates slowly (1–5 RPM) to continuously mix and move material through the heating zones
Material flows by gravity from the feed end to the discharge end
The heating system (direct or indirect) maintains precise temperature profiles
Combustion gases or electrical heating elements provide the required thermal energy
