Ruthenium
Also: Ru, Ruthenium (PGM)
Ruthenium (Ru) is a rare platinum-group metal with exceptional hardness and corrosion resistance, used chiefly in the electronics industry and as an alloying additive.
Ruthenium belongs to the group of platinum-group metals (PGMs) and is among the rarest elements in the Earth's crust. It was isolated in 1844 by the Russian-Baltic chemist Karl Ernst Claus and named after the Latin word for Russia. Despite its technical importance, ruthenium is far less well known to the general public than platinum or palladium.
Properties
Ruthenium is a silvery-white, brittle transition metal. With a value of 12.45 g/cm³ it has a high density and an exceptionally high melting point of 2,334 °C. Characteristic is its extreme hardness: even small ruthenium additions (0.1%) significantly increase the hardness of platinum and titanium. Ruthenium is extremely resistant to most acids; even aqua regia attacks it only slowly.
Extraction and occurrence
Ruthenium occurs almost exclusively as a by-product of nickel and copper mining, primarily in South Africa (Bushveld Complex) and Russia. Global annual production is estimated at 35 tonnes – a fraction of gold production. Refining is carried out via elaborate hydrometallurgical and pyrometallurgical processes.
Uses
| Application area | Share (approx.) |
|---|---|
| Electronics industry (resistors, HDD) | ~50% |
| Electrochemistry / chlor-alkali electrolysis | ~15% |
| Alloys (platinum, titanium, tungsten) | ~15% |
| Chemical catalysis | ~10% |
| Other | ~10% |
In the electronics industry, ruthenium is used for chip resistors and as a coating for hard-disk platters (antiferromagnetic coupling layer). In catalytic-converter technology it serves as an active component for ammonia synthesis and the Fischer-Tropsch reaction. As an alloying additive it gives platinum jewellery particular wear resistance.
Market significance and price discovery
The ruthenium market is narrow and opaque: there is no exchange fixing as with the LBMA fixing for gold or silver. Prices are negotiated bilaterally between producers and buyers and published by analysis houses such as Johnson Matthey and Argus Media. The historical prices show sharp swings – ruthenium was at times traded below USD 40 per troy ounce, yet also reached highs of over USD 700 (2007). For investors the market is barely accessible owing to the lack of standardised trading products and low liquidity. (Not investment advice.)
In brief
Ruthenium is a high-technology metal with an indispensable role in electronics and catalysis, but scarcely present in the investor market. Those who follow the price development of related PGMs gain an indirect picture of the ruthenium market – a standalone investment, however, remains reserved for institutional players and specialists.