Recycling, Metals

Abstract

Abstract The methods of recycle for various nonferrous metals of economic importance are detailed. Principal metals are aluminum, copper, lead, and zinc, although cobalt, nickel, tin, and precious metals such as gold, silver, and palladium are also recycled. Types and sources of scrap and waste metal are given. Much recyclable material arises from discarded automobile parts, beverage cans, and industrial metal industry wastes. Factors that influence the decision to recycle by pyrometallurgical or hydrometallurgical means are discussed. These processes are described, including the types of furnaces employed for smelting operations and the extractants used for solvent extraction systems. Recycling of nonferrous metals is heavily dependent on the economics of using secondary metal feed rather than ore. The role of waste management is also considered. Ferrous scrap recycling is a principal worldwide activity. The primary consumers of ferrous scrap are steel mills and iron and steel foundries. These depend on scrap for a large fraction of their iron‐based raw materials. The U.S. is the leading exporter of ferrous scrap. It exported about 10.9 × 10 6  t in 2004. The several sources and types or grades of ferrous scrap are presented including descriptions of supply, demand, and exports. Primary uses of ferrous scrap are discussed. Concerns about residual elements from both environmental and product quality point of view are discussed. Standards and environmental regulations are reported. Recycling of ferrous scrap is dependent on iron and steel industry processes and demands. Low residual scrap is preferred.