Used core sand

Sand obtained upon decoring of castings.

This sand was subjected to high thermal loads; it comprises core residues and bentonite-bonded molding material (sand adhering to the casting). This sand does not contain either bondingbentonite or lustrous carbon carriers (except any present core binder residues).  The sand particles are separated from the molding material cycle and must be replaced, if required.

Additional references:
Mold material management
Mold material control
Sand reclamation
Sand regeneration