Study On Methods Of Semi-coke Preparation Of Activated Carbon

As the coal low-temperature carbonization of solid product, semi-coke has been widely applied in many fields with its unique property of “three tall four low”. In recent years its downstream ferroalloy, iron and steel industry are excess capacities, and their demands for semi-coke are reduced, so semi-coke industry needs to develop new applications. It has become a critical research direction for semi-coke preparation of activated carbon with its cost advantage of the relations.In this paper, Shanxi semi-coke as raw material, was prepared of activated carbon by physical activation and chemical activation method. Ash pretreatment of semi-coke was mixed with 20% coal tar as a binder and modeled at 10 Mpa pressure. Activated carbon was prepared by carbon dioxide activation method under the best conditions: carbonization temperature was 400?, activation temperature was 900?, activation time was 2.0h, the flow rate of carbon dioxide was 0.4L/min. The yield of products was 48.56%, the iodine adsorption value was 995.07mg/g, the BET specific surface area was 558.02m2/g, the average pore diameter was 3.20 nm and the BJH pore volume was 0.274cm3/g. While activated carbon was prepared by KOH activation method under the best conditions: activation temperature was 900 ?, activation time was 1.0h, alkali/carbon ratio was 3. The yield of products was 29.69%, the iodine adsorption value was 1258.64mg/g, the BET specific surface area was 1975.81m2/g, the average pore diameter was 0.86 nm and the HK pore volume was 0.274cm3/g.Because the pore forming principle of chemical activation method is very different from physical activation method, there is a big difference between the two preparations of activated carbon on microscopic. Pore size distribution curves shows that the preparation of activated carbon with physical activation mothed is a middle pore developed activated carbon, and pore size is mainly in 3~11mm, While the preparation of activated carbon with chemical activation mothed is a micro pore developed activated carbon, and pore size is mainly in 0.8~0.9mm. FTIR spectra revealed that the activated carbon prepared by the physical and chemical activation methods contains many hydroxyl and carboxyl functional groups which could influence the sorption capacities and catalytic capacities. But the comparison is found that the activated carbon prepared by the chemical methods also contains a lot of ether groups and more unsaturated bonds.