JOM World Nonferrous Smelter Survey, Part II: Platinum Group Metals

摘要

The platinum group metals (PGMs) are a family of six grayish to silver-white metals with close chemical and physical affinities. The three heavier metals, platinum (Pt), iridium (Ir), and osmium (Os), have densities of about 22 g/cm~3. The three somewhat lighter metals, palladium (Pd), rhodium (Rh), and ruthenium (Ru), have densities of about 12 g/cm~3. The PGMs belong to the transition metals of Group VIII in the periodic table, as do iron (Fe), nickel (Ni), and cobalt (Co). These metals have similar geochemical behavior and tend to be concentrated together geologically. The PGMs, along with gold (Au) and silver (Ag), are classified as noble metals because of their high resistance to oxidation and corrosion. Their great scarcity classifies them as precious metals. Only about 1/13 as much platinum is produced as gold, itself a very rare metal. (By contrast, about 5 million times as much iron as platinum is produced in the world.) As precious and noble metals, PGMs are chemically more versatile than gold, and have found numerous industrial applications. They are also the only competitors for gold