The Hot Strength of Industrial Cokes – Evaluation of Coke Properties that Affect Its High‐Temperature Strength

The strength of coke at high temperatures is of major importance for efficient blast furnace operation. Despite this, there is little information regarding the hot strength of coke. In this research, the hot strength of three industrial European coke grades was studied using a Gleeble thermomechanical simulator. The hot strength was analyzed at three different temperatures: room temperature, 1600 and 1750 °C by measuring the compressive strength of roughly 50 coke samples at each temperature. A significant decrease in strength was observed for all three coke grades at high temperatures. Notable differences between the coke grades in compressive strength were observed at room temperature. At high temperatures, differences were observed in strength and deformation behavior; however, the order of magnitude of strength remained the same. The deformation behavior at high temperatures was also studied and discussed based on stress–strain curves. Several structural properties of coke such as total porosity, pore size distribution, pore shape factor, amount of inerts, and degree of graphitization were determined in order to explain the obtained strength results. Both hot and room temperature compressive strength values were compared to industrial strength tests and discussed. The reliability of the results was evaluated with statistical analyses.