Extraction and recovery characteristics of Fe element from Nd-Fe-B sintered magnet powder scrap by carbonylation

Iron element was extracted from the powder scrap of Nd-Fe-B sintered magnets via the carbonylation reaction with sulfur as a catalyst. The resultant carbonyl complex was Fe(CO)5 and the yield was evaluated to be ∼56% by energy dispersion X-ray analysis. After applying the hydrogenation disproportionation treatment on the powder scrap, the extraction rate for Fe element was considerably accelerated on the resultant α-Fe/Fe2B/NdH2 (or neodymium oxides) nanocomposite powders to produce Fe(CO)5 in a maximum yield of ∼92%.