Metals Production and Metal Oxides Reduction Using Hydrogen: A Review

Hydrogen is projected to be not only a source of clean fuel energy, but also a reducing agent for metals production in the current industrial decarbonization effort. Currently, hydrogen is still not common to be used in many metals production. Hydrogen is only commercially utilized in a limited number of refractory metals (i.e., W, Mo) and partly utilized in Ni and Co metals production. Hydrogen reduction of metal oxides has been extensively studied at laboratory scale, particularly in regard to kinetics and reaction mechanism. These studies provided the fundamental knowledge useful for the development of the industrial metals production process. Recently, experimental approaches, current applications, and technologies related to the hydrogen reduction of metal oxides have been further developed. The current paper reviews selected key studies and provides information on the current status and applications of hydrogen for reduction of metal oxides (with a focus on reduction kinetics and mechanisms of non-ferrous oxides). This study summarized that hydrogen has the potential to be used to recover valuable metal from secondary resources (e.g., Zn from EAF dust, Pb from slag) but further detailed fundamental studies are required for improved processes. The use of hydrogen was also found to be useful for a number of advanced material processing, beyond extractive metallurgy perspective.Graphical Abstract