Reduction Test of Artificial MIO (Micaceous Iron Oxide Fe₂O₃) Doped with Na₂O and K₂O and Natural MIO

　In order to examine the effect of alkali component on iron ore reduction, reduction tests were made using artificial MIO (Fe₂O₃ single crystals). MIO was grown in conc. NaOH or KOH solution by hydrothermal method and contained Na 0.12wt% or K 0.20wt%, respectively. It is considered that Na₂O and K₂O form solid solution in Fe₂O₃ crystal. In this experiment CO was generally used as reduction gas. After reduction the surface of the specimen was observed with SEM. In marked contrast to the reduction of artificial Fe₂O₃ grown by flux method (Na, K trace) and natural MIO (Na trace, K 0.01wt%), in this case fibrous iron grew intensely and the growth postition had no dependence on crystal plane index of Fe₂O₃. It is surmised that lattice defects coused by the solution of alkali element would enhance swelling phenomena during reduction.