Platinum group metals: annual review 1996.
Although the metals of the group are generally found together, minable deposits of the PGM are rare. Often, the PGM are byproducts of the mining of other metals, usually nickel or copper.
Identified world PGM resources at year-end 1996 were estimated at 100M kg. The reserve base was estimated at 66M kg and reserves at 56M kg. Of the reserve base and the reserves, South Africa had nearly 90% of each; Russia had 9% and 11%, respectively; and the United States had 1% and 0.4%, respectively.
In the United States, the Stillwater mine in Montana accounts for nearly all domestic primary PGM production. Production at the Stillwater mine, consisting primarily of palladium and platinum, increased in 1996, reflecting the progress made in the company's four-year plan to increase ore production from 336K mt/yr to more than 660K mt/yr by mid-1997. In 1995, Stillwater produced 1,590 kg platinum and 5,260 kg palladium, while in 1996, the mine produced nearly 1,840 kg platinum and 6,100 kg palladium.
The remaining primary PGM produced in the United States were byproducts of the refining of primary copper; they were recovered from anode slimes at two copper refineries in Texas and Utah. In addition to the small amount of byproduct production, about 20 refiners, located primarily on the east and west coasts, recovered PGM from scrap material. Other companies located throughout the United States collected scrap materials, such as catalysts and PGM-bearing solutions, and processed them to increase the grade. These upgraded secondary materials were then sold to refiners. Most companies specialized in refining or upgrading a particular type of scrap. Because of their high value, PGM are routinely recovered from petroleum catalysts, chemical catalysts, automobile catalysts, glass fiber bushings, electronic scrap, laboratory equipment, dental materials, and jewelry. PGM were sold by at least 90 processors and dealers, largely in the northeastern United States.
South Africa remained the world's largest PGM producer, accounting for 80% of platinum production and 44% of palladium production. Essentially all of South Africa's PGM output was produced by 10 mines, nine of which are underground operation, mining the Bushveld complex. The Bushveld complex and the Stillwater complex are the only deposits in the world mined primarily for their PGM content. Canada and Russia are the other major producers of PGM. For both countries, PGM are byproducts of their nickel operations, primarily in the Sudbury District of Canada and the Noril'sk-Talnakh region of Russia.
The principal use of PGM in the United States was in the catalytic converters of automobiles and light tracks, where they reduce the carbon monoxide, unburned hydrocarbons, and nitrogen oxides in exhaust gases to tolerable levels. Other automotive applications include oxygen sensors and certain types of spark plugs, both of which used small quantities of platinum.
The nonautomotive applications of PGM were numerous. The petroleum refining industry used PGM, principally platinum, in reforming, cracking, and isomerization reactions. Other PGM catalyst applications include the syntheses of nitric acid and hydrogen peroxide using palladium. PGM catalysts were also used to produce a variety of organic chemicals.
Electronic applications for PGM include the production of thick-film resistors using ruthenium, the production of thick-film conductors using palladium, and the use of platinum "targets" for sputtering thin film on circuit boards. Platinum-rhodium alloys were used in thermocouples for precise temperature measurement.
In addition, platinum, rhodium, and palladium were used in the "bushings" through which textile glass fiber is extruded.
The Engelhard average price for unfabricated platinum decreased from $425.32/tr oz for 1995 to $398.17/tr oz for 1996. Similarly, the Engelhard average price for palladium decreased from $153.46 for 1995 to $130.41 for 1996. For 1996, the Engelhard average price for iridium was $74.00; for rhodium, $308.80; and for ruthenium, $47.56. In 1995, the average prices were $74.14, $464.66, and $26.72/oz for iridium, rhodium, and ruthenium, respectively.
Platinum stocks held by the New York Mercantile Exchange (Nymex) increased to 2,844 kg at year-end 1996 from 1,188 kg at year-end 1995. Nymex year-end palladium stocks rose to 3,064 kg from 2,149 kg. Stocks of PGM held by the U.S. federal government in the National Defense Stockpile remained unchanged from the previous year, and at year-end 1996 consisted of 14.1K kg platinum, 39.3K kg palladium, and 920 kg iridium.
The United States remained dependent on imports of PGM. For 1992-96, the United States imported more than 318K kg platinum. Of this amount, South Africa supplied approximately 60%, the United Kingdom 10%, and Russia 9%. During the same period, the United States imported more than 500K kg palladium. The major source countries were Russia, 42%; South Africa, 22%; and the United Kingdom, 11%. All unwrought and semimanufactured PGM can be imported duty-free.
Though platinum, palladium, and rhodium are so efficient in automotive catalysts that they have no competitive substitutes, the percentage of each metal used in the catalyst can be varied. Silver and gold are alternatives for platinum and palladium in many end uses.
World Review. Johnson Matthey estimated that world demand for platinum, nearly 152 st, was essentially unchanged in 1996. Although platinum use in automotive catalysts declined owing in part to a shift by some manufacturers to palladium-rich catalysts, the decline was more than offset by the estimated increase in demand in the form of small investment items for jewelry and for petroleum catalysts. Similarly, the world demand for palladium in 1996, as estimated by Johnson Matthey, also remained essentially unchanged from 1995. Increased demand for palladium for automotive catalysts was more than offset by lower demand for electrical applications.
Outlook. Given the strong demand for a cleaner environment, worldwide demand for PGM is expected to grow moderately over the next few years. Many countries already require the use of catalytic converters for controlling emission from gasoline-powered automobiles, and other countries are expected to adopt these requirements. Although both platinum and palladium are used in catalytic converters, in the short term, platinum remains the dominant metal, owing primarily to the need to use up to three times as much palladium to obtain the desired emission reduction. Domestically, moderate growth for PGM demand is also expected over the next few years as increasingly stringent standards for automobile emissions are adopted.
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|Publication:||E&MJ - Engineering & Mining Journal|
|Date:||Oct 1, 1997|
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