Dynamic wettability of liquids on gasified metallurgical cokes

For blast furnace iron-making, understanding the flow behavior of molten iron and slag on the surface of metallurgical coke will lead to optimal design of burden material, which strongly influences the gaspermeability of the furnace. Since the surface structure of coke changes as the reaction of carbon with CO₂ or iron oxide progresses, wettability and motion of liquid in the coke-packed bed may be influenced depending on the reaction ratio of coke, i.e., the surface structure. In the present study, to investigate the influence of the surface structure of coke on liquid flow behavior, the advancing and receding contact angles of mercury and water on coke were measured. Of the two liquids, mercury has the higher surface tension. The surface structure of the coke substrate was varied by heating in CO-CO₂ or CO₂ atmospheres at 1 273 K. It was found that the fine irregularities of the coke surface formed by the gasification reaction of the carbon increases the receding contact angle of water but has little influence on the dynamic contact angle of mercury. Depending on the results, influence of surface property of coke on flows of molten iron and slag in the blast furnace is discussed.