Platinum An Invaluable Earth Resource Essay Research

Platinum: An Invaluable Earth Resource Essay, Research Paper

Platinum: An Invaluable Earth Resource

The advent of the Industrial Revolution sparked worldwide large-scale use of minerals in the mid 18th and early 19th centuries, as well as continued growth during the next several hundred years. Over a period of 150 years from 1750-1900, global mineral use saw an increase of roughly 1000 percent while the world population merely doubled. Since 1900, mineral production has increased roughly 1300 percent (Young 6), and the world has become completely dependent upon the various uses of limited mineral resources. One mineral which has provided numerous uses for several diverse industrial markets is the valuable metal platinum (Pt).

Platinum is the most well known and widely used member of the six platinum metals of Group VIII, Period 6, of the periodic table. In order of increasing atomic weight, the platinum group metals are ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and the focus metal, platinum (Pt). Excluding osmium, all the aforementioned elements are silvery white in color.

According to historical record, gold artifacts containing platinum have been dated to approximately 700 BC; however, the presence of platinum in these materials was most likely accidental, or unknown. Similarly, 16th century Jesuits made reference to unidentified metallic pebbles contained within gold bars, making them brittle and hard to refine. These pebbles were most likely platinum based metals. Despite early sightings of platinum group metals, the pure, malleable platinum known and used today was not discovered until 1789 by French physicist P.F. Chabaneau. Upon its discovery, Chabaneau felt it worthy to present before Pope Pius VI in the form of a chalice, or trophy.

Geographic distribution of platinum is quite limited and appears in large quantities in a select few sites. The largest known deposit of platinum is found in the Bushveld Complex of South Africa, a country well known for its exquisite diamonds. Additional large deposits are located in the Sudbury deposit of Ontario, Canada, and the Norilsk-Talnakh deposit of Siberia in the former USSR. Montana’s Stillwater Complex is the major U.S. excavator of platinum-based metals, however, in comparison, U.S. production is miniscule compared to the aforementioned countries.

Three individual layered reefs of the Bushveld Complex in South Africa–the Merensky Reef, the UG2 Chromite Layer, and the Platreef–produce the country’s most significant amounts of platinum group metals (PGM). The PGM occur as alloyed native metals, as platinoid minerals, and in copper, nickel, cobalt, and iron sulfide minerals. (Hilliard FFF4) South Africa produced roughly 174,000 kilograms of PGM in 1998, a 2 percent increase from 1997 figures. In 1998, the Krasnoyarsk nonferrous metals plant produced 95 percent of all Russian PGM and most likely exported every ounce of the total 100, 000 kilograms that were recovered. (Hilliard FFF4) The Krasnoyarsk plant reportedly struck a deal with Impala Platinum Holdings Ltd., a South African based mining company, to ship platinum ores to be refined in Russia and then exported as pure metal beginning in 1999. Supposedly the deal would increase Krasnoyarsk plant operating capacity 5 percent to a total of 35 percent. (Hilliard FFF4) Canadian PGM output was much smaller in comparison to Russia and South Africa, coming in a distant third at 7,570 kilograms for 1998 production. The United States rounded out the top four with 1998 annual production at 3,240 kilograms of PGM. (Hilliard Table 2)

Mineral reserves are defined as “known and identified deposits of earth materials that can be extracted legally with economic efficiency, by using existing technology.” It is estimated that world reserves of platinum group metals in mineral concentrations presently or potentially economic to mine are in excess of 100 million kilograms. (Hilliard 127) South Africa alone is believed to hold around 63 percent of the world’s PGM reserves , which equates to nearly 63 million kilograms of the precious metals. This figure places South Africa at the top of the world reserve list for PGM. Russia captures the number two spot with a mere 6.9 million kilograms of reserves, while the United States follows in third with about 800,000 kilograms. These figures indicate that the supply of platinum and its PGM counterparts will be unlikely to run out in the near future.

Aside from small alluvial deposits of platinum, practically no ores exist where platinum is the major metal. Usually, platinum based minerals are widely dispersed in sulfide ores such as pentlandite [(Ni, Fe)9S8], laurite (RuS2), irarsite [(Ir, Ru, Rh, Pt)AsS], osmiridium (Ir, Os), cooperite (PtS), and braggite [(Pt, Pd)S]. (Brittanica, Platinum Group) Most of the major platinum deposits are exploited through underground mining techniques. As mentioned prior, basically all platinum group metals are extracted from copper or nickel sulfide minerals that are concentrated by floatation separation. Smelting of the concentrate produces a matte that is filtered of copper and nickel sulfides in an autoclave. (Brittanica, Platinum Group) The filtered material is composed of 15 to 20 percent platinum group metals.

Of all metals, the platinum group is among the most difficult and time consuming to separate from ore. Sepa