Blast furnace operation at high productivities, low coke rates and long campaign life requires excellent coke properties regarding chemical and physical criteria. This paper describes the role of the coke in blast furnaces, summarizes actual coke qualities charged to European blast furnaces considering low coke rate operation, and points out coke quality requirements suitable for smooth blast furnace working. Special emphasis is given to the high temperature properties of coke expressed by the CSR and CRI values. CSR indices below 60 percent are not accepted to avoid higher pressure losses in the furnace and to guarantee a permeable hearth. CRI should be in the range of 20 to 30 percent. Blast furnace results showed that with increasing CSR indices, the injected coal levels could be increased with a remarkable decrease in total reductant rate and a considerably improved shaft gas permeability. Unwanted chemical elements charged with the coke to the blast furnace should be kept as low as possible. Regarding imported coke, it is important that quality data are evaluated by internationally agreed test procedures in order to make data comparable.
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