Carbon Transfer in the Lower Zone of a Blast Furnace

In this paper results from an investigation focused on coke/iron reactions occurring in the hearth of a blast furnace, below the slag layer, are presented. In this region, as coke dissolves in the iron there is the potential for a mineral layer to form and persist at the coke/iron interface and inhibit the rate of coke dissolution. Key findings of the investigation include that the composition of the mineral layer was principally composed of oxides of aluminium and calcium, present as various calcium aluminates and that the morphology of the layer profoundly affected the rate of carbon transfer. Follow-up up studies on the kinetics of carbon transfer focussed on how the wetting and interfacial characteristics of iron on the calcium aluminates would affect iron penetration of the mineral layer are also reported and discussed as was a new material, called coke analogue, that could be used in the study of real industrial coke. Analysis of the wetting behaviour of liquid iron on alumina and the calcium aluminates investigated indicated that iron wetting of the mineral layer was not a key parameter in coke dissolution in iron for the coke composition studied. The brief details given for the coke analogue indicated that it did replicate coke dissolution behaviour in iron, though more experimental work is required to fully understand and exploit the potential of this material