Abstract: A device for removing foreign material from sand is disclosed. The device includes a rotary box which is driven such that sand is centrifuged therein. The box includes a circular bottom plate, a circumferential and inclined wall extending from the circular end of the bottom place, upwardly and outwardly, and ring portion which extends inwardly from the top of the inclined wall. A plurality of rollers are disposed in the box, each roller having a movable surface substantially parallel to and spaced apart from the circumferential and inclined wall of the box. Sand in the rotary box is centrifuged and circumferentially deposited on the inclined wall to form a sand layer which becomes progressively thicker and then contact the movable surface, subjecting the sand to shearing and compressive forces. Processed sand then overflows from the ring portion of the rotary box.