Platinum

Platinum (Pt) is the best known of the 6 greyish-white, metallic, platinum group elements, which also include palladium (Pd), iridium (Ir), rhodium (Rh), osmium (Os) and ruthenium (Ru). Platinum and palladium are more commonly used than the other elements in the group. The melting points and specific gravities of these elements are as follows: Pt, 1769°C and 21.45; Pd, 1552°C and 12.02; Rh, 1960°C and 12.41; Ru, 2310°C and 12.45; Ir, 2443°C and 22.65; and Os, 3050°C and 22.6. Osmium and iridium are the densest metals. This group of "noble" metals possesses a combination of unusual qualities: high melting points; chemical inertness; and, most importantly, exceptional catalytic properties, even when temperatures are high and corrosion is a problem. The best known use of platinum, palladium and rhodium is in automotive catalysts to clean vehicle exhaust.

In its native form, platinum is alloyed with small amounts of other platinum group metals, appreciable amounts of iron and, often, COPPER, NICKEL or SILVER. The Spaniards, encountering it for the first time in native jewellery in South America during the 16th century, called the metal platina or "little silver." In the early 19th century, platinum was isolated as an element.

Platinum is a rare precious metal. Less than 10% of platinum is bought for investment. Platinum is valuable because it is scarce but very useful. Automobile catalysts and jewellery are the 2 principal uses, accounting for 77% of platinum demand. Industrial catalysts, fuel cells and electronic applications are other important uses for platinum. Palladium's 3 major uses are in automotive catalysts, and dental and electrical applications. Rhodium is almost exclusively used in automobile catalysts. Japan is the largest consumer of both platinum and palladium, accounting for 37% and 32% respectively of world demand.

Russia and South Africa are the main suppliers of platinum and palladium; they produce about 177 t and 171 t respectively. Russia produces more palladium than platinum, while the reverse is true for South Africa. In South Africa, platinum group elements are extracted from sedimentary deposits in the Bushveld Complex near Pretoria. In Canada and Russia, platinum is an important by-product of nickel-copper production. Russian production comes mostly from mines at Norilsk. Most Canadian production has come from INCO LTD's and Falconbridge Ltd's nickel-copper mines in the Sudbury Basin. In 1993, North American Palladium Ltd opened its mine near Thunder Bay, Ont. Palladium is the main product; platinum is a by-product.