Blending a coking charge on the basis of a comprehensive coal property index

Coal suitability for high-grade blast-furnace coke production is indicated by a recently-devised index based on the difference between the temperature of maximum rate of loss of plastic mass and the temperature of solidification of plastic mass. The optimum range of values for the index is -20 to +5 C. The Yasinovka coking plant charge index of -21 C fell outside this range, but Pechora and Karaganda coals with indices of -16 and -8C respectively lay within the range. Semi-commercial scale tests showed an improved charge composition with higher Karaganda coal content. The M/sub 25/ index of the coke was increased by 3.8% and the M/sub 10/ by 2.5%.