US Patent 7955583 Metallic silicon and method for manufacturing the same

This metallic silicon is manufactured by refining molten crude metallic silicon by unidirectional solidification, and has a purity of 3N or more to 6N or less and an average crystal grain diameter of 1 mm or more. This method for manufacturing the metallic silicon includes: solidifying molten crude metallic silicon in a mold which contains fine silica particles in an inner peripheral layer thereof by unidirectional solidification at a rate of 1 mm/min or less; and then cooling to 200° C. or below at a rate of 2° C./min or less.