Influence of the Crushing of Bituminous Batch on Coke Quality

Laboratory and industrial research confirms that decrease in the clinkering properties of bituminous coal when it is present to excess in the coking batch improves the strength of blast-furnace coke. If coal batch containing >70% bituminous coal is crushed until its content of the ≤3 mm class is 90%, the crushability Π₂₅ may be increased by 1.8%, with decrease in the susceptibility to wear И₁₀ by 0.8%. This behavior may be explained in that increase in the specific surface of the coal particles reduces the fluidity of the plastic mass and hence increases its viscosity. Consequently, the residence time of the gaseous products in the plastic zone increases. That results in the formation of a large quantity high-molecular gas, creating higher expansion pressure. The overall outcome is greater utilization of the destruction products as plasticizers; the formation of additional liquid from the gaseous products within the grains; and improvement in the contact conditions.