scrapis generated while manufacturing alloy magnets for
VCMs, which is the primary application of Nd. This scrap
contains not only sludge powder that is produced when
machining the magnet, but also ‘‘off-spec’’ products in which
the impurity of oxygen content exceeds the required
specification. Even though approximately 50% of Nd
charged as feed material is disposed of as scrap during the
manufacturing process, Nd is currently not being recycled.
This is because Nd forms an extremely stable compound with
many elements including oxygen, which makes it very
difficult to reuse or recycle the scrap. Most developed
countries import almost 100% of their Nd requirement, and a
high percentage of the valuable material is simply disposed
of without being utilized as a product. Considering the fact
that a large proportion of the total Nd produced worldwide
comes from a few particular countries,2) the establishment of
an efficient process for the recovery of Nd from alloy scrap is
a major concern from the point of view of better industrial
policy as well as secure resource procurement.