Role of Al₂O₃ in interfacial morphology and reactive wetting behaviour between carbon-unsaturated liquid iron and simulant coke substrate

Wetting between liquid iron and coke influences liquid flow in the lower part of a blast furnace, which strongly affects the operation of the furnace. With increasing fluidity, the blast furnace performs more favourably and efficiently. To further improve blast furnace operation, the wetting behaviour of liquid iron on coke must be correctly understood. The effects of ash in the coke on reactive wetting in concave formations, such as holes formed at the contact area, must be considered. This study aims to elucidate the effects of the ash component in coke on the reactive wetting behaviour of carbon-unsaturated liquid iron on a simulant coke substrate and concave formations thereof. In this study, reactive wetting between the iron samples and the substrates was measured by a sessile drop method with a molten injection system at 1 673 K. The results revealed that the apparent contact angle significantly decreased with time in the first 300 s after contact. After 300 s, the contact angle stabilized at a constant equilibrium value. The initial contact angles depended not only on the carbon concentration of the liquid iron, but also on the Al₂O₃ content in the substrates. Concave geometries formed when the carbon-unsaturated iron samples were wetted on substrates containing 0, 5, and 10 vol% Al₂O₃. The effect of Al₂O₃ on the carbon dissolution reaction was the main factor affecting the reactive wetting behaviour of substrates against liquid iron.