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12
Metal Refining and
Purification
As Chapter 4 pointed out, aluminum alloys produced by remelting scrap are less
valuable than alloys with the same composition produced from primary metal. The
reason for this is concern over the purity of the recycled metal alloy, which is often
inferior to that of primary. The development of rening technology for molten alu-
minum is designed to eliminate this deciency, which will allow recycled metal to
compete with the primary in more applications. Much of the technology used for
rening molten aluminum has been introduced only in the last 30 years, and what
was once a minor footnote in an aluminum pro