
87Beneficiation Technology
(Ridall,2009). While color separation cannot separate aluminum from other white
metals such as magnesium, it can potentially be used to separate painted from bare
scrap (Gesing, 2006). This reduces the amount of unnecessarily decoated material
and thus the cost.
The use of x-ray technology to identify scrap pieces has become a signicant
element in sorting owsheets over the past decade. X-ray transmission (XRT)
through scrap pieces is blocked in proportion to the thickness of the piece and
the atomic number of the metal and can be used to distinguish aluminum from
heavier metals such as copper and stainless steel without ...