Reoxidation of Hot Briquetted Iron in Salt Water

摘要

The reactivity of HBI in salt water was investigated by immersion in aerated salt-water solutions. 1. Products of HBI corrosion were identified by Raman spectroscopy as being adherent goethite, and flocculent oxides, predominantly lepidocrocite. 2. Oxidation was not limited to the surface of the briquettes, but penetrated the interior. Briquettes having been subjected to saline contamination showed catastrophic degradation during later storage in air, possibly due to the hygroscopic nature of salt. 3. The controlling mechanism is thought to change from reaction controlled, to diffusion control with the formation of the goethite layer. 4. Oxygen diffusion is not thought to be fast enough to replace oxygen used in reaction due to blockages of pores by product, and oxygen being used to further oxidize oxides. 5. Salt contamination has an effect on the corrosion of HBI and iron compacts. The chloride ion, which is thought to act as a catalyst to the reaction has an effect on the corrosion rate when it is primarily reaction rate controlled. This effect decreases as the rate becomes more diffusion controlled. However concentration changes in the range 24.0 - 29.4 g/L of NaCl were not found to have a significant effect on either the extent, or the rate of corrosion over the eight-week period. 6. The results from this study compare well to data generated for commercial HBI