Why add foundry chromite sand during casting? Chromite sand is often used as the surface sand of large steel castings in casting production, which can effectively prevent sand from sticking to the surface of castings and improve the quality of castings. It has a stable heated volume and high thermal conductivity. It has a good resistance to alkaline slag when in contact with molten metal, and it has the characteristics of solid phase sintering, which can well prevent the penetration of molten metal and avoid the occurrence of sand sticking defects.