1st Paragraph: In this work, a kinetic model based on solid-state diffusion is formulated to describe the growth of the hercynite (FeAl2O4) spinel formed as a result of the interaction between FeO and Al2O3 under conditions relevant to the novel flash ironmaking technology (FIT) which has been developed at the University of Utah. Experiments were conducted with FeO powders and pure Al2O3 refractory in the temperature range 1200 – 1400°C under relevant gas atmospheres and analyses of reacted samples using XRD, SEM-EDX and EPMA techniques showed that the proposed kinetic model appropriately describes the growth of the hercynite spinel layer, which obeyed the parabolic rate law at all the three temperatures. Furthermore, using the kinetic model expressions for the parabolic rate-constants (𝑘1) and the effective diffusivity (𝐷𝑒𝑓𝑓) were obtained and their respective values at the experimental temperatures were determined. The activation energy for the solid-state diffusion was calculated as 268 kJ/mol.
Authors: Rahul Sarkar and Hong Yong Sohn
Keywords: Flash ironmaking, alumina refractory, solid-state diffusion