Article ID



Recycling of Rare Earth Magnet Scraps: Part III, Carbon Removal under Vacuum Heating


A. Saguchi, K. Asabe(Sumitomo Metals Industries, Ltd.), W. Takahashi(Sumitomo Metals Industries, Ltd.), R.O. Suzuki and K. Ono


Mater. Trans., 43[2] pp.256-260 (2002).


The removal of the carbon from Nd-Fe-B magnet scraps is indispensable for high-quality recycling by induction melting method as a preliminary process. The decarburization under reduced pressure was developed by using the Nd-Fe-B magnet grinding sludge that is highly contaminated with carbon and recycling has been assumed to be difficult. The grinding sludge scrap was effectively decarburized without generating an excessive iron oxide by heating under reduced pressure. The decarburized powder was deoxidized by using the molten salts reduction with Ca, which has large affinity with oxygen. Consequently, the decarburized powder could be deoxidized even the level that can be melted industrially. In this research, the preliminary process using the Nd magnet grinding sludge scraps before induction melting is described.