An Overview of H₂ and CH₄ as Environmentally Sustainable Alternative Reductants to C for Chromite Smelting

The application of hydrogen (H 2 ) and methane (CH 4 ) as gaseous reductants for pure chromite (FeCr 2 O 4 ) is reviewed in four theoretical approaches. These approaches are evaluated against the conventional process, where the sole reductant is a solid carbon (C) source. The sustainability is measured by gaseous carbon monoxide (CO(g)) formation, determined by the reaction stoichiometry of each theoretical approach. Decreased CO(g) formation is critical for alleviating the adverse environmental impact of ferroalloy production. The prereduction of FeCr 2 O 4 by H 2 , followed by reduction by CH 4 shows the largest decrease in CO(g) formation, i.e., a 75% decrease, compared to the conventional process. Furthermore, the H 2 ‐based prereduction and CH 4 ‐based primary reduction occur at lower temperatures than C‐based reduction, due to kinetic advantages, and thus decrease energy consumption. The overview discusses the environmental impact of substituting C with H 2 and CH 4 and briefly discusses how it can be implemented in industry.