Analysis of the Deadman Features in Hearth Based on Blast Furnace Dissection by Comprehensive Image-processing Technique

Abstract

Information of the coke packing condition and its size distribution in the deadman is critical for understanding the blast furnace hearth phenomenon. In this study, a commercial blast furnace was frozen and dissected. It was found that the upper part of the deadman below the taphole was mainly filled with coke and slag. In the area from the height of about 912 mm below the taphole and downward, the hearth was mostly consisted of coke and hot metal and the depth was about 2320 mm. The bottom part of the hearth with a height of 214 mm was coke free and filled only by hot metal. A multi-feature analysis method based on comprehensive image-processing technique was used for measuring the size of the coke and the voidage of the deadman. It was found that the mean sizes of coke in the upper and lower parts of deadman were 34.39 mm and 32.12 mm respectively. The overall mean size of coke was 33.3 mm. The size of the coke in the deadman was reduced by 36% comparing with its original size. At the edge of the deadman, the voidage increased rapidly from 10.7% to 41.1% at the depth of 1.0 m to 2.2 m below the taphole centerline. In the centre of the deadman, the voidage increased slowly from 16.6% to 31.3% and then decreased. The average voidage of the edge and the centre areas were 38% and 25% respectively.