Metal casting in a sand mold having a sodium bentonite clay binder mixture

摘要

Molten metal is cast into a mold cavity formed of sand held in a predetermined mold configuration by a binder comprising a plurality of sodium bentonite clays. A blend of two or more sodium bentonite clays obtained from different areas as a foundry sand binder synergistically and unexpectedly improves the foundry sand used as a mold cavity for casting metal objects by unexpectedly improving one or more of the following foundry sand properties beyond the level of either of the blended sodium bentonites alone: green compressive strength; hot compressive strength; dry compressive strength; wet tensile strength; flowability; surface finish; activation speed and shakeout.