Ruthenium Metal

Ruthenium Metal And Alloys

Ruthenium Metal

Ruthenium is a rare member of the platinum group of metals (abundance 0.001 ppm in the earth's crust). It is a lustrous, silvery colored metal which is unaffected by air, water and acids, but is soluble in fused alkalis. Extraction of the metal is achieved by several techniques; for example, extraction of the mixed platinum group metals by dissolution in aqua regia, followed by treatment of the various soluble and insoluble fractions. Applications of the metal are limited; as a pure metal, ruthenium is extremely hard and brittle and, consequently, difficult to machine. It is relatively unreactive, and is used as an alloying element with platinum and palladium to produce alloys which have improved wear resistance, and with titanium to improve the material's corrosion resistance. In all cases, the ruthenium addition has to be less than 15%, otherwise the resultant alloy is too hard to work.

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Ruthenium

Ruthenium, together with rhodium, palladium, osmium, iridium, and platinum form a group of elements referred to as the platinum group metals (PGM).

Ruthenium is a hard, white metal. It does not tarnish at room temperatures, but oxidises in air at about 800°C. The metal is not attacked by hot or cold acids or aqua regia, but when potassium chlorate is added to the solution, it oxidises explosively. It dissolved in molten alkalis.

Applications

Ruthenium demand is rising: the metal find use in the electronic industry (50%) and the chemical industry (40%), with smaller amounts being used in alloying. In electronics it used to be used mainly for electrical contacts but most now goes into chip resistors. In the chemical industry it is used in the anodes for chlorine production in electrochemical cells.

The metal is used as a hardener for palladium and platinum and added in small amounts improves the corrosion resistance of titaniumin. It is used in electrical contact alloys and filaments, in jewelry, in pen nibs, and in instrument pivots. It is also used in alloys with cobalt, molybdenum, nickel, tungsten, and other metals. Ruthenium compounds are used to color ceramics and glass.

Ruthenium is also a versatile catalyst, used for instance in the removal of H2S from oil refineries and from other industrial processes, for the production of ammonia from natural gas, and for the production of acetic acid from methanol.

Some ruthenium complexes absorb light throughout the visible spectrum and are being actively researched in various, potential, solar energy technologies.