State of Deadman in Blast Furnace Hearth and Its Internal Phase Distribution Characteristics

The state of deadman in hearth is important for the long campaign life of blast furnace (BF). In order to clarify the influence of deadman on sidewall erosion, the corresponding relationship between the shape of deadman and sidewall erosion was studied, the fundamental reason for the difference of sidewall erosion was analyzed, the influence mechanism of slag-coke interface and iron-coke interface on the coke in deadman was explored based on the phase distribution in deadman. The results show that: The shape of circumferential bulge at the root of deadman is a common feature of BFs, this feature is the main reason for the serious erosion of sidewall, and the serious erosion area of sidewall corresponds to the root position of deadman. The deadman shows a dynamic evolution law of sinking and floating under the action of force in the smelting process of BF, the depth of slag and iron level in hearth has the greatest influence on the deadman. The difference of central voidage of deadman is the fundamental reason for the difference of sidewall erosion for BFs in which the deadman is in the same floating state. Slag-coke interface and iron-coke interface commonly exist in hearth. The dissolution reaction at iron-coke interface makes carbon in coke continuously migrate into molten iron, which makes the graphitization degree of coke increase, the coke is easy to pulverize, this is the main mechanism of coke deterioration and renewal in deadman. The enrichment of harmful element K at slag-coke interface makes the coke expand and crack, the coke matrix is easier to peel off, which accelerates the deterioration process of coke.