Vitrinite micrograph

Figure 3. Optical micrograph of the semicoke from carbonization of the hydrogenated Phalen Seam coal at 550°C OV, oxidized vitrinite...

Figure 12. Electron micrograph of an tdtrathin section of vitrinite in hvab coal. X 116,900...

With increasing rank, the differences between macerals become progressively smaller in electron as in light microscopy. Exinite in particular becomes difficult to distinguish in medium volatile coals, and could not be positively identified in the electron micrographs of low volatile bituminous coals so far examined. Similarly, the laminate structure of vitrinite described above could not be observed in low volatile bituminous coals. 

Figure 6 is a TEM micrograph of a region of vitrinite in the Illinois No. 6 coal obtained at high magnification (50 K) in order to perform a more detailed analysis of the porosity associated with this maceral. Pore dimensions range from 1 to 10 nm, which classifies them as a mixture of micropores (<2 nm) and mesopores (2-50 nm). The observation of porosity in the two-dimensional image becomes more difficult as the specimen thick-... 

In addition to those minerals associated with the granular constituent, there are numerous submicron-sized minerals that are intimately mixed with other coal macerals. A typical example can be seen in Figure 11, which is a TEM micrograph of vitrinite, where the circular aperture identifies the region from which the electron diffraction pattern, shown in the inset, was obtained. The mineral, which was identified as kaolinite, appears to have been deposited as plates parallel with the coal bedding, based upon an analysis of the diffraction pattern. Also present in these coals is the clay mineral illite, which can be distinguished from kaolinite by both EDX and SAD analyses, lllites contain potassium (K)... 

Figure L Electron micrograph of coalesced spheres in Pittsburgh No. 8 vitrinite on the heating stage of the TEM,...

Figure 2. Electron micrograph of isolated spheres in Illinois No. 6 vitrinite.

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