INFLUENCE OF KIND AND PARTICLE SIZE OF SEMI-SOFT COKING COALS ON DILATATION OF BLENDED COAL

摘要

Recently, in an environment in which the fluctuations of coking coal price increase, in order to produce high strength coke at a low production cost, it is required that the blending technology applied to various kinds of coal. The dilatation of coal is one of the significant factors determining coke strength. It is known that in the case of blended coal that contains semi-soft coking coals, the dilatation value of blended coals does not agree with the weighted average value of coking coal and semi-soft coking coal, and it shows lower than the weighted average value. In this study, for the purpose of developing of the coal blending technology applied to various kinds of semi-soft coal, we investigated the inhibitory influence of kind and particle size of semi-soft coking coals on the dilatation of hard coking coal. In consequence, when the dilatation value of semi-soft coking coal is extremely low, the inhibitory influence on the dilatation of hard coking coal becomes high. As the particle size of low dilatation semi-soft coking coal becomes finer, it becomes higher. Moreover, we have clarified that the inhibitory influence on the dilatation of hard coking coal is dominated by the pore structure of semi-coke derived from semi-soft coking coals.