Effect of Nitrogen-less Reducing Atmosphere on Permeability of Cohesive Layer in Blast Furnace

Abstract

Recently, demands for reduction of CO₂ gas emission in iron making process are increasing. For further reduction of CO₂ gas emission, a method of capturing carbon dioxide from blast furnace exhaust gas has been studied. The oxygen blast furnace using pure oxygen for blast does not contain nitrogen in the exhaust gas and that is more advantageous than conventional blast furnace in the point of view of CO₂ separation energy. Although the oxygen blast furnace has been studied with the experimental furnace, the experimental furnace was not sufficiently investigated on the properties of cohesive layer because of the small load of burden materials. Therefore, in this study, the properties of cohesive layer of the oxygen blast furnace were studied.

The properties of the cohesive layer were evaluated under blast furnace conditions and nitrogen-less conditions in a load-softening test. As a result, the properties of cohesive layer were remarkably improved in nitrogen-less conditions. As a result of discussion, improvement of the properties of cohesive layer was quantitatively explained due to suppression of contraction of the sintered ore and the decrease of slag liquid because the nitrogen-less atmosphere promoted reduction reaction.