Utilisation of Metallurgical Wastes

IN various metallurgical treatments, by-products inevi-tably result; their utilisation is also inevitable as the challenge of competition in the face of gradually leaner ores, becomes irrefutable. Utilisation of metallurgical by-products and metallurgical wastes extends to both ferrous and non-ferrous metallurgical operations. The scope of this subject is vast indeed when examined in the context of utilisation of liberated industrial gases, spent pick-leliquors, flue dusts, slimes, ore tailings, slags, swarfs, skimmings, residues, ashes, drosses, etc. It is estimated overseas that secondary smelters of brass and copper derive half of their requirements of secondary scraps from industrial by-products and wastes; recovery
of secondary lead from discarded storage batteries, pipes, sheaths, type metal, babbits, etc. is another example. Whilst the primary metallurgical production techniques may yield byproducts relatively easier to handle, metallu-rgical wastes resulting from secondary processing
schedules will require high metallurgical ingenuity for their maximum economic utilisation. The recovery of cadmium as a by-product in zinc and lead extraction and of cobalt in copper extractive metallurgical operations will illustrate the issues involved.