**5.1 Scrap reduction and scrap usage**

Due to the intrinsic ability of the casting technique to produce cleaner castings, it is more adaptable to the use of scraps and foundry returns. These types of foundry feedstock contain significant admixed impurities like moulding sand and oxide inclusions. Such scrap metals produce significant slag which float on the melt surface.

The process of taking the melt can actually be used to pump clean metal below the melt surface. Figures 10 and 11 respectively show the micrographs of gravity-pour ceramic mould cast samples and countergravity cast samples of scraps of aluminium foundry returns. The microstructure shows more segregation of melt impurities in the gravity-pour ceramic mould, while the vacuum cast specimen shows significant reduction in impurities.
