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Interaction of Pure Alumina Refractory with FeO–SiO 2 and FeO–SiO 2 –CaO Slags Relevant to the Novel Flash Ironmaking Technology
Author(s) -
Sarkar Rahul,
Sohn Hong Yong
Publication year - 2019
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201900104
Subject(s) - feal , electron microprobe , materials science , diffusion , activation energy , analytical chemistry (journal) , slag (welding) , oxide , scanning electron microscope , metallurgy , atmospheric temperature range , mineralogy , chemistry , thermodynamics , intermetallic , alloy , physics , chromatography , composite material
Interaction of alumina (Al 2 O 3 ) refractory with FeO–SiO 2 and FeO–SiO 2 –CaO slags relevant to the flash ironmaking technology (FIT) is investigated in this work. It is shown that for slags relevant to FIT, the interaction process can be described by a kinetic model based on counter diffusion of only Fe 2+ and Al 3+ cations through hercynite (FeAl 2 O 4 ) formed as a result of the interaction. The diffusion of Si 4+ and Ca 2+ ions through FeAl 2 O 4 can be neglected, and the only effect these cations have is that they affect the activity of iron oxide (FeO) at the slag–FeAl 2 O 4 boundary. Analyses of reacted samples using X‐ray diffraction (XRD), scanning electron microscopy–energy dispersive X‐ray spectroscopy (SEM–EDX), and electron probe microanalyzer (EPMA) show that the proposed model appropriately describes the growth of FeAl 2 O 4 with the parabolic rate law being obeyed for both FeO–SiO 2 and FeO–SiO 2 –CaO slags in the temperature range of 1200–1400 °C. The values of effective diffusivity (D eff ¯ ) are calculated independently from experiments with FeO–SiO 2 and FeO–SiO 2 –CaO slags agreed with each other, with the activation energy values in the two cases being 246 and 253 kJ mol −1 , respectively. These values ofD eff ¯and activation energy are in good agreement with the corresponding values obtained previously from Fe–Al 2 O 3 and FeO–Al 2 O 3 systems.