The influence of coal segregation on the physicochemical properties of the blend during charging of coke ovens

It is shown that the ash content of coal is unevenly distributed by size classes. The 25–50 mm class has the highest average ash content (13.1 % wt.), but exhibits significant variability (6.8– 32.1 % wt.). Smaller classes (< 0.5 mm) have a higher ash content (up to 15.1 % wt.) compared to the average sizes (10.9 % wt. on average). The stability of the technological properties of the coal charge during injection was confirmed, however, there are discrepancies in particle size, volatile matter yield and ash content, which increased from the center of the tower to its outer rows. Additionally, segregation may cause problems with coke discharge. Uneven ash distribution within the coal blend results in the formation of coke zones with elevated mineral content, which deteriorates the mechanical strength of the coke (M10, M40) and adversely affects blast furnace operation, particularly in terms of slag formation and coke consumption.