Methods and apparatus for separating polysilicon powder from a mixture of granular polysilicon and polysilicon powder are disclosed. The method includes tumbling the polysilicon material in a tumbling device. The tumbling device includes a tumbler drum having one or more lifting vanes spaced apart from one another and extending longitudinally along an interior surface of the tumbler drum. The lifting vanes facilitate separation of polysilicon powder and granules as the tumbler drum is rotated about its longitudinal axis of rotation.