Preparation of reduced iron powder for powder metallurgy from magnetite concentrate by direct reduction and wet magnetic separation

The Hoganas method is considered the most effective method for producing reduced iron powder (RIP). How-ever, this method does not remove impurities; therefore, high-purity magnetite must be used as raw materials. In this study, when RIP was produced using magnetite concentrate (TFe = 64.86%), a strong raw material flexi-bility was observed. The influence of various parameters on the preparation of RIP was studied. The results showed that pyrite was the optimal additive, and when used under optimized conditions, it produced RIP with a high iron grade of 99.65%, which meets the standard for powder metallurgy. Analysis revealed that the pyrite additive formed a molten iron sulfide (FeS) phase. Spheroidal metallic iron particles were more easily encapsu-lated by the FeS phase; consequently, the symbiotic relationship between iron and gangue was minimized, which was more conducive to the separation of metallic iron and oxides impurities. Thus, a high-purity RIP was produced. (c) 2021 Published by Elsevier B.V.

Automated summary

The Hoganas method is used to produce high-purity reduced iron powder by adding pyrite as an optimal additive, resulting in RIP with an iron grade of 99.65% under optimized conditions. This method facilitates the separation of metallic iron from oxide impurities by forming a molten iron sulfide phase.