2005 Volume 45 Issue 12 Pages 1820-1827
Coke texture is most important quality factor of blast furnace coke. A coke, as descends in blast furnace, it should retain essentially the same shape but is not true. In coke, its strength is associated with the microstructure and texture. The carbonization of coals leads to the development of coke that exhibits a variety of microscopic textures whose optical behavior in polarized light aids in their characterization. The optical microscope provides the most appropriate method for measuring these features. In this study nine coke samples of different coal blend made by stamp charging technology (Wet Bulk density 1.15tm-3) were used and an attempt has been made to examine the microtexture of stamp charged coke in range of 23.4 to 24.6% volatile matter to predict coke strength by microtexture and possibilities of establishing vitrinite distribution-coke texture relationship, if any. Results indicate that cokes contain significant proportion of isotropic carbon and different size of anisotropic carbon. Anisotropic carbon is less reactive to carbon dioxide compared to isotropic carbon and the strength after reaction depends on its anisotropic texture. With an increase in isotropic carbon M10 index deteriorates and coke reactivity index increases. In this study it was also found that all the carbon forms mentioned do not correlate well with vitrinite distribution and hence, it can be stated that micro petrographic parameters are generally not sufficient for expressing decisive properties of coke; since, coke microstructure and texture has been recognized to be of prime importance in controlling and improving the physical properties of coke.
