The invention is a method of separating metals such as zinc, lead and cadmium from iron in secondary feed stocks such as EAF Dust, BOF Sludge, mill scale, iron fines, tire dust and other iron and zinc containing residues and dusts. The method includes the steps of reduction roasting the feed stocks at a volatizing temperature sufficient to volatilize the zinc and other metals into metal fumes but insufficient to volatize iron and then collecting the metal fumes as a metal dust. The metal dust is then leached with a leaching liquid to form a leach liquor and a leach residue. The leach liquor is then purified by zinc dust cementation to form a purified liquor and a zinc dust cement residue. The purified liquor is then separated from the zinc dust cement residue, and a zinc recovery step is then performed on the purified liquor.