Difference in Radial Direction of Lumpy Coke Sampling from Raceway of Large Blast Furnaces: Microstructure, Alkali Enrichment, and Solution Loss Reaction

In this article, the morphology, chemical structure, alkali enrichment, and solution loss reactivity in the radial direction of the lumpy feed coke and its corresponding raceway coke from two large blast furnaces are comparatively using multiple characterization methods. The results indicate that the erosion of coke and pore development not only occurs on the surface but also in the center, which can be described as gradient reaction model. The enrichment level of K is higher than Na. K content decreases gradually from the edge to the center of the raceway coke, and the formation of nepheline causes cracks in coke observed by morphology. The crystallite order of the raceway coke is higher than that of the feed coke, with the enrichment of alkali metals, the raceway coke shows variability in the radial direction, and the orderliness gradually decreases from the surface to the interior. With the enrichment of alkali metals, the microcrystalline ordering of the raceway coke decreases from the surface to the interior, and the increase in the concentration of carbon dioxide after the entry into the raceway leads to the preferential reaction of the carbon dioxide with the coke matrix which contains K and many reactive sites. The manuscript investigates radial differences between lumpy coke and raceway coke, changes in structure and composition, and results that alkali metal enrichment, pore structure also differ and are closely linked to the degree of structural ordering, and that alkali metals play a determining role in the reactivity of the coke.image (c) 2024 WILEY-VCH GmbH