Scaling-up a hydrogen reduction process to synthesise iron–nickel alloy from a mixture of metal oxide powder

The significant carbon dioxide emission and high-energy consumption from traditional pyrometallurgical metal alloy production can be eliminated by using hydrogen as a reductant and processing materials in the solid state. In this study, an iron–nickel alloy was synthesised by solid-state hydrogen reduction of 250 g of a 50 wt% Fe 2 O 3 -NiO powder mixture. The alloy was produced in a horizontal Fe-Cr-Al tube furnace in multiple steps. The metal oxide mixture was exposed to a reducing atmosphere from room temperature, ramped up to 700 °C over 30 min, and held at 700 °C for 3 h. X-ray diffractometry of the reduced product confirmed the absence of oxides and the presence of body-centred cubic and face-centred cubic phases. A trace amount of oxygen was identified by melt-extraction analysis. The oxygen content results encourage pilot-scale iron–nickel production and the broader application of this process for large-scale metal alloy production from metallurgical by-products.