An experimental study of a direct route from iron oxide superconcentrate to strip

Abstract

A direct route from commercially available high-purity magnetite superconcentrate to thin steel strip has been investigated on a laboratory scale. The experimental procedure was first to produce an oxide strip prepared from a thick aqueous slurry of the superconcentrate and an organic binder. After drying, the strip was reduced and sintered in hydrogen or a hydrogen-carbon monoxide mixture to produce a coherent strip of iron sponge. The sponge was then hot and cold rolled to give fully dense strip. In some cases a thin layer of iron powder was bonded to one side of the iron oxide strip in order to increase its coherence during processing. On a microscale the product is characterized by a fine grain size and a large number of uniformly distributed fine inclusions. The inclusions vary from 25 μm down to submicron size and are derived from the residual impurities in the concentrate, most of which were originally in the magnetite lattice. After suitable working and heat treatment, strength and ductility as measured by tensile testing appear to be similar to low-carbon steel strip produced commercially.