Abstract: A novel flash ironmaking technology (FIT) with greatly reduced energy consumption and CO2 emissions has been developed at the University of Utah. In this work, a solid-state diffusion based kinetic model is proposed to describe the growth of the hercynite (FeAl2O4) spinel formed as a result of the interaction between Fe (containing O) and Al2O3 under flash ironmaking conditions. Analyses of reacted samples from experiments in the temperature range 1200 -1500°C using XRD, SEM-EDX and EPMA showed that the proposed model appropriately describes the growth of hercynite layer, which obeyed the parabolic rate law at all temperatures. The parabolic rate-constants were obtained and the diffusion-controlled growth of the FeAl2O4 layer was strongly dependent on temperature. Furthermore, using the kinetic model an expression for the effective diffusivity (𝐷𝑒𝑓𝑓̅̅̅̅̅̅) was obtained and its values at the experimental temperatures were determined. The activation energy for the solid-state diffusion was 231 kJ/mol.
Authors: Rahul Sarkar and Hong Yong Sohn
Keywords: Flash ironmaking, alumina refractory, solid-state diffusion