Influence of coke reactivity on the ferric burden reduction of the lumpy zone in a blast furnace

The influence of coke reactivity on the ferric burden reduction of the lumpy zone in a blast furnace was studied by using five kinds of coke with different reactivities.The pressure drop and CO volume fraction of the burden layer as well as the burden reduction degree were also analyzed.It is found that the coke gasification rate,CO volume fraction of the burden surface,and burden reduction degree increase with the increase of coke reactivity.When the CO volume fraction(only considering CO and CO₂) of the original gas is 72.22%the burden reduction degree increases from 33.18%for low-reactivity coke to 53.83%for high-reactivity coke.When the CO volume fraction of the original gas is 66.67%,which is slightly lower than the CO theoretical equilibrium volume fraction of FeO reduction at 900℃, metallic iron can be obtained by means of high-reactivity coke.Therefore,appropriately increasing the coke reactivity in a blast furnace can promote the coupling reaction between coke and ferric burden,improve the CO volume fraction of the burden layer,and increase the burden metallization rate before going into the cohesive zone.