
204 Aluminum Recycling
The inclusions in remelted aluminum scrap are different than those in primary
metal, as Table 12.1 shows. Scrap inherently has more dirt and oxide in it than pri-
mary metal (Pyrotek, 2006), and the oxide skins generated during melting increase
the inclusion count even more (Altenpohl, 1998). As a result, inclusion removal is
much more important in secondary aluminum production. Remelting of bulky scrap
generates metal with fewer inclusions than remelted UBC or light scrap; the price
of bulky scrap is higher as a result (see Chapter 4). Remelting of high-magnesium
alloys generates a higher inclusion count, due to the g