Study on coke properties in deadman of blast furnace

Abstract

The coke particle size and porosity of the deadman can significantly influence the distribution of molten iron flow velocity in the hearth as well as carbon brick erosion. In this study, coke samples were collected from the deadman after a 1780 m3 blast furnace was shut down. The particle size, mechanical strength, microstructure, chemical composition, and degree of graphitisation of coke were analysed alongside the voidage distribution of the deadman. The average particle size and mechanical strength of coke gradually decreased along the vertical axis of the deadman. The average particle sizes of coke at the top and bottom of the deadman were 28.15 mm and 25.04 mm, respectively. The M25 of the coke at the top and bottom of the deadman were 87.9% and 79.1%, respectively. The basicity of the slag entering the coke was lower than that of the original slag due to alterations in its composition caused by the ash content in coke, resulting in a reduction in its basicity. The graphitisation degree of coke gradually increased from the top to the bottom of the deadman. The voidage of the deadman progressively decreases in a downward direction. At distances of 4.5 m and 1.5 m from the hearth bottom, the voidages in the central zone of the deadman were 36% and 27%, respectively. These results deepen our understanding of coke in the deadman.