A x-ray investigation was made on the relation between quality and graphite crystallite, size of commercial coke. At first, crystal sizes of foundry cokes carbonized at various parts in Semi-Koppers type industrial oven were measured. It was found that the sizes became larger in the order, “ upper part ”<“ central part ”<“ wall part of oven ”. “ Central part ” means the central part of acoke lump carbonized at about half height of the oven. This result well agrees with the temperature distri-bution in the oven. Next, it was found from the research of foundry cokes and electrode cokes that the crystal dimension of e axis direction of bitumen coke carbonized at a definite condition was inherent for their raw material origins. It was obtained from experimental data of the author and other workers that there was a linear correlation,
y'=-a+bx, in crystal grain of bitumen cokes and soots heated at a definite tempererature, where
y is the crystal dimension of e axis direction and is the dimension of a axis direction, the level of significance of the equation being found to be below 1% by the analysis of covariance. a and b are numerical constants different with difference of the group of raw materials. Three empirical equations were derived for electrode coke, coal coke and soot respectively, all heated about 1000°. From above investigations, the importance of blending raw material could be known.
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