Two-Stage Reduction of Iron Scale with Intermediate Magnetic Separation for High-Purity Iron Powder Production

Abstract

A two-stage process is proposed for reducing iron-containing mill scale waste, involving an initial carbon-based reduction step, followed by hydrogen reduction, with magnetic separation in between. The purpose is to produce high-purity iron powder while optimizing hydrogen usage. The carbon stage, using powdered charcoal as a reducing agent, reduces most of the iron oxides economically at 900°C for 60 minutes. Intermediate magnetic separation, conducted using a permanent magnet to attract the iron-rich phase, removes non-magnetic impurities (e.g., silicon, calcium, tungsten oxides). The final hydrogen stage, carried out at 900°C for 60 minutes under flowing hydrogen gas, achieves nearly 100% iron purity as confirmed by EDS analysis. This process reduces hydrogen consumption and promotes the sustainable recycling of metallurgical waste for high-quality iron powder applications.