Spindle-type ultrafine α-Fe₂O₃ particles were directly synthesized at pH＝4～7 under the conditions of boiling reflux in a short time. In this method, Fe₂(SO₄)₃ was used as raw material, NaH₂PO₄ as growth-regulating agent and trace FeSO₄ as catalyst. Compared to the forced hydrolysis method and hydrothermal synthesis, the proposed method was of characteristics of simple operation, high concentration, mild reaction condition, good reproducibility, etc. All kinds of factors that might affect the aspect ratios and phase transformation rate of spindle-type α-Fe₂O₃ were studied.

Key words: spindle-type α-Fe₂O₃, preparation, Fe^2＋ ion, phase transformation, catalysis