This least known of the platinum group metals has three traditional markets: -Process Catalysts – for the creation of ammonia (NH3) -Electrochemical – coating for electrodes for chlorine production -Electronics – resistor pastes for thick film technology However in the last 3 to 4 years two new industries have emerged which require large quantities of Ruthenium.
The first is as an addition in certain Nickel alloys for aerospace. The second is for the production of targets for use in high density data [HDD] storage systems.
Our role in the ruthenium market developed from our existing business as a supplier of rhenium for complex nickel base super alloys. The next generation of these alloys (4th generation) for the first time adds ruthenium alongside rhenium and emerged from a NASA sponsored programme to find the optimum ratio amongst elements for high pressure turbine blades. It was discovered that a ratio of approx. Re 6% and Ru 3% could raise operating temperatures by approx. 50 degrees C.
The main traded item is Ruthenium Metal Sponge Powder Ru 99.9% min. and while the alloy industry can use the larger fractions including pellet where possible, the electronics industry requires 100 microns max and preferably 2-4 micron. Today total Ru supply is thought to be around 30-35 mt/py with as much as 15-20mt consumed in the HDD field. This will present a problem for the aero space industry if the 4th generation alloy is fully commercialised as the tonnages required will be of a simillar order. It was partly in anticipation of this that the Ru price rose to USD$ 900 / toz in early 2007. At that price commercialization could not take place but with the market below half this price today the chances are looking better.
This unknown of the platinum group metals was discovered in 1808 by J A Sniadecki at the University of Vilno, and rediscovered in 1828 in Russia by GW Osann of the University of Tartu.
Ruthenium is one of the platinum group metals and occurs native as an alloy with other PGM’s, osmiridium / platinoid ruthenium and also in some sulphide ores. The typical concentrations of ruthenium are significantly lower than the Pt concentrations, with relative values of 10:1 (Pt:Ru). It’s abundance on the earths crust is therefore approximately 0.001 ppm.
It is mined in South Africa, Russia, Canada, USA and Zimbabwe with S.Africa and Russia the two main sources. Most of the ruthenium produced comes from Merensky and UG2 reef of the Bushveld Igenous Complex in S. Africa with a relation of Pt:Ru, 7:1 ~ 5-10 g/t. However in areas like the Stillwater mine (USA) the ores are richer with 25 g/t.
It has a grayish / silvery appearance and is very hard and brittle. It is unaffected by air, water and acids, but dissolves in most molten alkalis. It forms a volatile RuO4 which can decompose explosively as well as forming ruthenates and chlorides.
After mining, the PGM elements can be separated by electrolysis followed by chemical separation, ion-exchange and solvent extraction to give pure Ru. The metal is obtained from its compounds by hydrogen reduction.
It has several applications: Catalyst: – process catalyst ruthenium on graphite for ammonia synthesis. Electrochemical:- coating of electrodes for chlorine and chlorate manufacture. Electronics:- resistor pastes for thick films on circuit boards. Metallurgical:- to harden platinum and palladium metals. Today’s main use is in HDD drives where the Ruthenium helps to store more data by storing it vertically rather than horizontally.
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