Mosaic coke structure

Figure 5. Semicoke of oxidized Phalen Seam coal hydrogenated at 450°C and 1,5 MPa for 3 hr, showing a very fine grain, mosaic coke structure...

The process of development of a mosaic texture was observed by Taylor (2) first in thermally metamorphosed coals and then in partially carbonized vitrinite. He noted the appearance of spherical bodies in the plastic vitrinite, their growth, and the final development of the mosaic texture which is characteristic of the walls of the vesicular coke structure. From their appearance and behavior in polarized light it was deduced that the spherical bodies probably had a single plane of preferred orientation—i.e., a lamellar structure. 

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