A method of impregnating surfaces of objects with particulates comprising optionally, applying a liquid or semi-fluid binder to the objects to form pre-coated objects； adding the objects and particulates to a rotatable drum having at least an inlet, a length (L) and a diameter (D), the drum comprising at least 1 flight (200)； and rotating the drum wherein each flight lifts and then drops the objects and particulates (201), wherein the impact of the falling objects and particulates drives the particulates into the objects or into the coating of the pre-coated objects.
