Source Material Separation Of Mesophase Spherule And Preparation And Application Of Carbonaceous Mesophase

The possibility of mesophase generated by carbonization was investigated based on theraw materials of the four groups by the group separation of coal components, and theunderlying reasons of the asphaltene component which becomes the source material of themesophase spherule were analysed. The carbonaceous mesophase spherule and bulkmesophase were prepared from the raw material of the source material by the common thermalpolycondensation reaction. The effect of the factors that included carbonization temperature,carbonization holding time, heating rate and N₂flow rate on the formation process wereinvestigated. Afterwards, the optimum process conditions were determined and the evolutionlaws of the mesophase spherule were explored. Mesocarbon microbeads （MCMB） wereseparated from mesophase using a solvent extraction method and the particle size distribution,microcrystalline structure, etc. were characterizated. Activated mesocarbon microbeads（AMCMB） were prepared by KOH activation method and the effects of alkali-carbon ratio,activation temperature and activation holding time on holes structure, specific surface areasand yields of AMCMB were investigated, and the adsorption properties of AMCMB weremeasured by iodine adsorption value.The results show that the optimum process conditions of the source material to preparemesophase are the carbonization reaction temperature at450oC, holding time up to4h, theheating rate of4oC/min and100cm³/min of N₂flow rate. At this time, wide area streamlinedmesophase can be prepared with the soluble mesophase contents as high as41.3%. MCMBobtained by separating possess generally preferable sphericity with a very smooth surface andthe particles size distribution mostly are concentrated in the10²0m and MCMB contain agraphite-like structure of the microcrystalline with relatively large degree of crystallinity, thestructure of orderly lattice arrangement and the preferred orientation. At the optimum processconditions which are alkali-carbon ratio at5:1, activation holding time for1h and activationtemperature at900oC, the specific surface area of the prepared AMCMB is up to2636.5cm²/g,and iodine adsorption value reach2616mg/g.Under the optimum process conditions, mesophase spherules begin to appear during theholding time at0.5h¹h and spherules existe at each time point when holding time at2h withuneven distribution of particles size, wherein the diameter of the spherules with large particlesize increase with the holding time prolonged and the orderly arrangement of the bulkmesophase is formed until the holding time for4h. Carbonized products at different holdingtime contain a large number of polynuclear condensed aromatics and microcrystalline graphite-like structure. With the holding time extended, the degree of crystallinity tends toincrease,d₀₀₂gradually decreases, andL_c andL_a both increase. HS and HI-TS contents ofthe group components decrease gradually, TI-QS and QI contents, softening point and the truedensity gradually increase.A new theory called “Based nuclears-spherical inclusions coalescence” is proposed on thebasis of the coal-based mesophase formation from source material. The mesophase formationprocess includes five steps that are formation of the source material particles at roomtemperature, generation of the based nuclears of spherules, transfer and aggregation of thebased nuclears to form spherical inclusions, integration and growth of the spherical inclusionsand coalescence of the spherical inclusions to form spherules. This theory presents a reasonableexplanation to the formation processes of mesophase spherules and ultimate bulk mesophaseby carbonization of source material.