NICKEL PROCESSING

preparation of the metal for use in various products. Although it is best known for its use in coinage, nickel (Ni) has become much more important for its many industrial applications, which owe their importance to a unique combination of properties. Nickel has a relatively high melting point of 1,453 C (2,647 F) and a face-centred cubic crystal structure, which gives the metal good ductility. Nickel alloys exhibit a high resistance to corrosion in a wide variety of media and have the ability to withstand a range of high and low temperatures. In stainless steels, nickel improves the stability of the protective oxide film that provides corrosion resistance. Its major contribution is in conjunction with chromium in austenitic stainless steels, in which nickel enables the austenitic structure to be retained at room temperature. Modern technology is heavily dependent on these materials, which form a vital part of the chemical, petrochemical, power, and related industries. Additional reading Comprehensive and up-to-date information on many aspects of metallurgy, individual metals, and alloys can be found in convenient reference-form arrangement in the following works: Metals Handbook, 9th ed., 17 vol. (197889), a massive and detailed source prepared under the direction of the American Society for Metals, with a 10th edition that began publication in 1990; Herman F. Mark et al. (eds.), Encyclopedia of Chemical Technology, 3rd ed., 31 vol. (197884), formerly known as Kirk-Othmer Encyclopedia of Chemical Technology, with a 4th edition begun in 1991; and its European counterpart, the first English-language edition of a monumental German work, Ullmann's Encyclopedia of Industrial Chemistry, 5th, completely rev. ed., edited by Wolfgang Gerhartz et al. (1985 ). The Editors of the Encyclopdia BritannicaStill the only comprehensive reference focusing on nickel ores, both sulfide and oxide, is Joseph R. Boldt, Jr., The Winning of Nickel: Its Geology, Mining, and Extractive Metallurgy (1967); it covers geology, mining, mineral processing, and extractive metallurgy of nickel and associated metals such as copper and cobalt. Boldt's work can be updated, but not replaced, by A.R. Burkin (ed.), Extractive Metallurgy of Nickel (1987), which contains information on more recent hydrometallurgical and pyrometallurgical processes; and by G.P. Tyroler and C.A. Landolt (eds.), Extractive Metallurgy of Nickel & Cobalt (1988), which collects symposium papers on the latest developments in mineral processing, hydrometallurgy and pyrometallurgy, nickel-cobalt health effects, and particular plant operations. W. Betteridge, Nickel and Its Alloys (1984), a concise work from a series of surveys of industrial metals, focuses on chemical processes. John Campbell Taylor