Gravitational segregation

Segregation of melt with a considerable difference in density between the segregating components: the specifically heavier components fall in the liquid molten bath and the specifically lighter components rise to the molten bath surface.

Typical alloys for gravitational segregation are copper-lead alloys and Babbitt. Furthermore, high-melting intermetallic compounds (intermetallic phases) generated in aluminum alloy melt after a longer period of holding or components added for grain refinement may segregate and accumulate at the bottom of the holding vessel due to their higher density.

Another popular segregation is the gravitational segregation of primary graphite in hypereutectic gray cast iron which rises in the molten bath as kish graphite.

Additional references:
Segregation factor (secondary aluminum alloys
Segregation factor (cast iron)
Macro segregation, crystal segregation, micro segregation
Inverse macro segregation