Formation of a Mineral Layer during Coke Dissolution into Liquid Iron and Its Influence on the Kinetics of Coke Dissolution Rate

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Process metallurgy and materials processing science, 2008-06, Vol.39 (3), p.418-430
• Main Authors: Chapman, Michael W., Monaghan, Brian J., Nightingale, Sharon A., Mathieson, John G., Nightingale, Robert J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Calcium; Carbon; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coke; Dissolution; Exact sciences and technology; Kinetics; Materials Science; Metallic Materials; Metals. Metallurgy; Nanotechnology; Production of metals; Structural Materials; Surfaces and Interfaces; Thin Films
• ISSN: 1073-5615; 1543-1916
• DOI: 10.1007/s11663-008-9145-7

The formation and development of the mineral layer that forms between coke and liquid iron during carbon dissolution has been characterized. Coke particles (−2 mm, +0.5 mm) were added to the top surface of an iron 2 mass pct C melt at representative iron-making temperatures, for periods of time between 2 and 120 minutes, before being quenched. The quenched samples were then sectioned, and the solidified coke-melt interfacial region analyzed in the scanning electron microscope (SEM). Analysis showed that a mineral layer was present at the interface at all experimental temperatures (1450 °C to 1550 °C) from 2 minutes and persisted beyond 120 minutes. The mineral layer was found to be composed of calcium aluminate phases, with the proportions of these phases dictating its morphology. Further, changes observed in the rate of carbon dissolution from the coke were related to the composition and morphology of the mineral layer. The effect of this mineral layer on the rate of carbon dissolution has been interpreted as a change in the reaction control mechanism.