In order to clarify the coke degradation mechanism in the lower part of blast furnace, several kinds of model experiment were conducted based on the conditions that are possible to occur in the above region by considering the reaction form, reaction temperature, reaction degree and impact energy with 15 kinds of coke having different strength and reactivity.
In the above region, the control reaction affected more on the coke degradation and fine generation is CO2 gasification than contact to molten FeO or contact to molten metal. As coke is received CO2 gasification, fine (-1mm) is generated from the degraded part by abrasion.
One property of coke with less fine generation is that having high cold strength (I 6001≥ 86%) and low reactivity (CRI≤25%), and the other is that having high cold strength and high reactivity (CRI≥45%). In the former coke, CO2 gasification is gathered only on the surface of particle, and in the latter coke, CO2 gasification is occurred in the whole area of particle.
From now on, the coke breakage mechanism in the above region will be expected to be researched.