Effect of magnetic field on reduction of iron oxides: magnetite and wüstite

Abstract

A STRONG magnetic field (500–1,400 Oe) was reported by Skorski¹ to cause an increase in the reduction rate of haematite (Fe₂O₃) to metallic iron when H₂ was used as the reducing agent. This effect was attributed to the magnetic properties of the H₂, because neither CH₄ nor CO produced a similar increase when under the influence of a strong magnetic field. Although Svare² disputed this explanation, Peters³ offered an alternative one, based on thermodynamics, which indicated that an increase in reaction rate is expected under the influence of a strong magnetic field when the reactants were relatively non-magnetic and the products were strongly magnetic—as with reduction of haematite to iron. We report here our results of studying magnetite and wüstite reduction to iron, which show an increased reduction rate for magnetite, under the influence of a strong magnetic field, but an inexplicably decreased rate for the wüstite reduction.