High-tech uses for platinum group metals

The four other platinum group metals (pgm) — rhodium, iridium, ruthenium and osmium — are found mostly in association with platinum and palladium, except for the rare natural alloys osmiridium (80% Os) and iridosmine (77% Ir) recovered from gold and other ores in South Africa and the Soviet Union.

Canada mines (in byproduct form) a small amount of these four elements.

Rhodium, ruthenium and osmium are listed by the U.S. government as materials linked to the continuing evolution of high technology fields such as electronics, catalysis and energy.

Not long ago, I was asked what my fee was for a small service I was to render and I replied: “X oz of rhodium.” I’m happy to tell you rhodium is now the world’s most expensive precious metal and each ounce is worth around $1,200(US) per troy oz, that is, about $46 million(C) per tonne in value. Price nearly triples

Because of the formidable growth in its use in automobile converters, the price of the metal has grown to almost triple since its level of $450(US) per oz in 1977 and may top $1,600 by the year 2000.

Rhodium, much more expensive than platinum or gold, reduces nitrous oxide toxins in automobile exhaust fumes — its largest end- use, about 75% of the market. Non- communist world supply of rhodium amounts to 6-7.5 tonnes per year, roughly matching demand.

Western Europe consumption should increase, possibly to 3.3 tonnes per year, as new environmental regulations force greater growth in the use of 3-way (platinum-palladium-rhodium) catalyst systems in cars.

Rhodium automobile usage in western Europe already exceeds that in the United States, and for nitric acid output it takes about 4,000 oz per year, twice that of the United States.

Frequently used catalysts in the chemical industry include 0.5% rhodium on 1/8-inch alumina pellets and as 5% powder on carbon and alumina.

Platinum-rhodium alloys are used as electrical resistance heating elements, as windings for muffler furnaces operating to 1800 degrees C or higher, sealing devices, hot wire ignition systems, nylon cutters and cigarette lighters. Rhodium gives a hard, brilliant and tarnish-free surface, used in expensive mirrors instead of silver. Firm demand

Rhodium-platinum alloy spinnerettes or bushings are used in the manufacture of fiberglass. Each bushing weighs up to 10 kg but during operations, bushing metal is lost through diffusion and evaporation. Glass and chemical demand for rhodium has remained firm.

Further increases in world rhodium consumption appear inevitable. The qualities of rhodium are so unique it is unlikely it will be replaced by other metals or materials in its various applications.

Iridium, which comes mainly from South Africa, was formerly the most expensive precious metal. From 1977, the price rose in 10 years from $250(US) per oz to $450 and it may reach $550 by 2000.

Platinum-iridium is used in the mining and construction field in explosive detonators. Its single largest use is in the electrical industry and it is especially useful in the expanding fibre optics field and in producing optical glass for TV screens.

Ruthenium, the least expensive pgm, is now showing promising uses in ammonia catalysts. An important use is as ruthenium oxide coated on titanium anodes in the manufacture of chlorine and caustic soda; this applicati on consumes more than 2.4 tonnes ruthenium per year in the non-communist world and should grow by 20% by 2000.

About eight tonnes of the metal is consumed per year and demand remains steady. Its single largest use is in the electronics industry, about four tonnes per year, in thick film pastes. The price grew from $33(US) per oz in 1977 to $68 a decade later and may go to $150 by 2000.

Osmium is almost useless. Nevertheless, the price grew from $130(US) per oz in 1977 to $650 in 1987 and has exceeded $1,000 at times. About one tonne is consumed annually.

Limited uses of osmium include its application in tetroxide form as a staining medium for medical fat globule tissue specimens in electron microscopy. Osmic acid is used in the detection of fingerprints. Osmium is the heaviest of all known metals.003

(Tom) Mohide, a former president of the Winnipeg Commodity Exchange , served as a director of mining resources with the Ontario Ministry of Natural Resources prior to his retirement in 1986.

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