1. Raw Material Selection

The first step in the production of columnar activated carbon is choosing the right raw material. Common sources include:

• Bituminous coal

• Anthracite coal

• Coconut shell

• Wood

For most columnar activated carbons, coal-based materials are preferred due to their high carbon content, mechanical strength, and stable pore structure.

2. Crushing and Mixing

The selected raw material is crushed into fine powder, then mixed with a binder such as pitch or tar. The binder ensures proper adhesion and allows the powder to be formed into cylindrical pellets during extrusion.

3. Extrusion and Shaping

The blended mixture is then extruded into uniform cylindrical shapes—typically diameters of 1mm, 2mm, 3mm, or 4mm. This process gives columnar activated carbon its characteristic form and size.
The shaped pellets are dried to remove excess moisture and improve their strength before activation.

4. Carbonization

The dried pellets are then subjected to carbonization at temperatures between 600°C and 800°C in an oxygen-free atmosphere. During carbonization:

• Volatile matter is removed.

• The structure of the pellets becomes more porous.

• A basic carbon skeleton is formed, ready for activation.

5. Activation Process

The activation stage is the key to producing high-quality activated carbon. There are two main activation methods:

Steam Activation

Hot steam (800–1000°C) is introduced to react with carbonized pellets. This process develops a well-developed pore structure and high surface area (typically 900–1200 m²/g).

Chemical Activation

Less common for columnar carbon, this involves using chemicals like phosphoric acid (H₃PO₄) or potassium hydroxide (KOH). It’s mainly used for wood- or biomass-based carbons.

6. Cooling and Screening

After activation, the carbon is rapidly cooled to prevent oxidation. The pellets are then screened and graded according to size and quality. Dust and broken pieces are removed to ensure uniformity.

7. Impregnation or Surface Modification (Optional)

Depending on the application, the activated carbon may be impregnated with chemicals such as potassium iodide, sulfur, or silver.
These modifications enhance performance for specific uses—like H₂S removal, air purification, or mercury control.

8. Packaging and Storage

Finally, the finished columnar activated carbon is packed in moisture-proof bags or drums to preserve quality. Proper storage conditions are essential to prevent contamination or adsorption of unwanted gases.

Applications of Columnar Activated Carbon

Thanks to its high surface area, uniform shape, and strong adsorption capacity, columnar activated carbon is used in:

• Air purification and gas treatment

• Water purification

• Solvent recovery

• Desulfurization and denitrification systems

• Industrial exhaust and VOC control