One of our most popular products is coal based activated carbon as it’s highly customizable with a variety of granule and powder sizes, but also thanks to its high adsorptive power which lends itself to a range of applications.

In this article, we’ll show you how our state-of-the-art Asiacarb activated carbon factory in Jiangsu makes some of the finest quality activated charcoal for our diverse customer base around the world.

Step 1: Selecting Raw Coal

To get the highest quality activated carbon from coal, we analyze the types of coal we use in the process and select various types such as bituminous and anthracite coals. We understand that the final product needs to be strong, with a high carbon content but at the same time it must have a low ash content. We only use the best coal for a finished product with more than 90% hardness and excellent adsorption values.

Step 2: Crushing

We take the raw coal and crush it down to the size of mesh required for each customer order, a step that’s vital for creating the right adsorption capabilities. Some customers prefer to use a powder with a 200 or 325 mesh which can also be used in activated charcoal pills, but others will require a large 6 x 12 mesh or 8 x 30 mesh which is perfect for gas and liquid filtration.

Step 3: Powdering

It’s at this stage where we pulverize the coal even further to help it create the kind of very fine pore structure it needs. Carbon made this way is extremely microporous and is used for a wide range of applications such as recovery of solvents and gold, or for an activated carbon air filter. We analyze the fineness of the powder at this stage and can prepare it to be extruded or pelletized, whatever our customer desires.

Step 4: Extruding & Adding Coal Tar

Where the activated carbon for our customers needs to be pelletized, we mix the coal with tar (or sometimes pitch) so that it can form a cylinder-like pellet to create a certain size ranging from 1mm up to larger 7mm sizes. This extrusion process gives it a very high strength and a uniform shape that can be used in a range of industrial applications, for example, catalytic reactions.

Step 5: Stock Chest

Before the full carbonization process, we store our coal in a stock chest which allows it to cool to the right temperatures. This keeps the moisture distribution perfectly equal, and this stabilization beforehand will prevent the activated carbon we create from being structurally weak, brittle, and crack easily when we put it through the very high temperatures of the next step.

Step 6: Carbonization

The secret to developing high strength, impurity free activated carbon is this carbonization stage where we heat the coal slowly to temperatures as high as 400°C in an environment that is lacking oxygen. Lots of VOCs are removed here as the weight of the coal diminishes by over 70%, leaving us with a much more concentrated carbon. The initial pore structure is also created at this stage, which will be further enhanced in the stages to come.

Step 7: Stock Chest

After carbonization, we put the coal back into the stock chest to cool it down slowly and allow it to stabilize. If it is cooled too slowly at this stage, it can become brittle and crack due to thermal shock. When it has stabilized, it’s ready for its main phase where pores are developed.

Step 8: Activation

The coal undergoes its activation in this stage as we heat it to 1000°C with steam or CO₂. This process helps to develop all of the pores it needs to function effectively, boosting its surface area and adsorption capabilities. Large pores (macropores) are ideal for solvent recovery, medium-sized pores (mesopores) can be used in decolorization, and the smallest pores, (micropores) are ideal for air and gas filtration.

Step 9: Screening & Winnowing

As every customer order is different, the screening and winnowing process means we check every batch to make sure that our activated carbon factory is delivering the very highest industry standards for our coal based product. The activated carbon adsorption capabilities are checked whether the customer wants en polvo, granular, o pelletized activated carbon, depending on whether they need it for an activated carbon air purifier or water filter.

Step 10: Packaging

The final step is adding our product to the correct packaging so it gets to our customer intact and ready to use. You can choose from 25kg bags of the activated charcoal, or if you prefer you can opt for much larger 500kg bags when you need activated carbon in larger quantities. It’s given a label so the origin can be traced, then shipped around the world to wherever our customer is.

If you’d like to learn more about our process whether you need it for an activated carbon filter or another use, you can reach out to us by phone or email for cost-effective activated carbon solutions direct from China.