Coal-based activated carbon making

How to make activated carbon from coal?

As we all know, coal activated carbon is made by a series of coal activated production sections including carbonization, activation, cooling, crushing, screening, washing and etc. Carbonization and activation are two essential sections.

Step1: raw material preparation

In principle, all types of coal-based materials can be made into activated charcoal, however, the quality of activated carbon produced by different types of coal is very different, to meet the requirements of the market and make full use of resources, it is necessary to select raw materials before carbonization.

Step2: coal carbonization process

Carbonization process is main hot process of coal-based activated carbon production line. The main carbonization equipment is a continuous carbonization kiln. During the carbonization process, most of the non-carbon elements are excluded, excluding the volatile matter and moisture in the raw materials, and the released elemental carbon atoms are combined into carbon particles, so that the carbon particles form preliminary pores and have the structure of the original form of activated carbon. After the raw material is carbonized, it is called carbonized material. The carbonized material already has a certain adsorption capacity.

Step3: Activation process

The commonly used activation process for coal-based activated carbon is the physical activation method, using water vapor, flue gas (a mixture of water vapor, CO2, N2, etc.), CO2 or air as the activation gas, and contact with carbonized materials at a high temperature of 800-1000 ° C, and all of them being activated. The activation process achieves the purpose of pore creation through three stages: opening the originally closed pores, expanding the original pores, and forming new pores. The activation is mainly through the activation reaction of the activation furnace to create pores.

Step4: finished product section

The finished product will be processed into different-sized activated carbon according to application, the finished product section mainly includes crushing, screening, and packing.

Note: equipment used in finished section

1. Crushing equipment of coal activated carbon production line adopts twin roller crusher, by adjusting the size of the gap between the double rollers, the particle size of the product is controlled to increase the yield of qualified particle size screening.
2. Screening equipment generally uses vibrating screener to screen the crushed material into three types: larger particle size, qualified particle size, and larger particle size.
3. In the actual activated carbon production process, multi-layer screens are often added to the vibrating screen to screen out products within several particle sizes, finally, the products with qualified particle sizes are packaged and sold. In industrial applications, 500kg/bag and 25kg/bag are usually used for packaging. In addition, in the production process, stone removers and iron removers are also used for special-purpose products to reduce the ash content of the products.
4. For powdered activated carbon, mainly use two processes of grinding and packaging. Grinding is now basically produced in most factories using Raymond mill equipment. By adjusting the analyzer of the mill, the finished powder carbon with a particle size of 200 mesh and 325 mesh can be produced.

Step5 washing section

For some special applications, the finished activated carbon will be further processed by pickling, alkali washing, water washing, and so on. Among them, the purpose of pickling is mainly to reduce the ash content of activated carbon and avoid secondary pollution caused by activated carbon during use, so that it can be better used in food or other industries. There are also some application fields that require activated carbon impregnation to achieve better adsorption.

Step6: pre-treatment

In addition to the above-mentioned general sections for the production of coal-based activated carbon, sometimes, it is necessary to go through a unique section for pretreatment before carbonization and activation.

The production of briquette crushed charcoal requires coal blending, milling, kneading, extrusion molding, crushing, and screening into qualified particle sizes before carbonization and activation.