Zinc dross isn't a manufactured product; not liable to duty even if it's a marketable product

Central Excise : For goods to be dutiable, conditions of section 2(d) (movable and marketable) and section 2(f) (manufacture) have to be satisfied; therefore, zinc dross arising in course of manufacture of galvanized tower parts is not liable to duty as it is, prima facie, not a manufactured product; though it may be marketable