| Abstract Scope |
Cathodes from spent batteries contain valuable elements in oxidized form - lithium, nickel, manganese, and cobalt - for which recycling is desirable for sustainability and economical reasons. Although recovering Li oxides and other compounds is economical, recycling Ni, Co, and Mn oxides into new cathodes remain tedious. It involves multiple steps, including separation, purification, reduction to pure elements, and reoxidation, which generate high amounts of waste and consume enormous energy. We demonstrate hydrous oxides - the products remaining after leaching out Li from spent cathodes – can be reduced by hydrogen to recover Ni, Co, and Mn in a single step. After oxide reduction, the Ni-Co-Mn alloys are utilized as “master alloy”, without separation into individual elements, for the melting and solidification of high-grade alloyed steels with Fe-Ni-Co-Mn composition. We elucidate the effect of chemical compositions of hydrous oxides on reduction kinetics, microstructural evolution, and chemical composition of master alloys. |