Ruthenium: Encyclopedia II - Ruthenium - Occurrence

Ruthenium - Occurrence

This element is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario and in Pyroxenite deposits in South Africa.

This metal is commercially isolated through a complex chemical process in which hydrogen is used to reduce ammonium ruthenium chloride yielding a powder. The powder is then consolidated by powder metallurgy techniques or by argon-arc welding.

It is also possible to extract Ruthenium from spent nuclear fuel, which contains an average of 2 kg per metric ton of Ruthenium. Ruthenium produced in such a way contains radioactive isotopes, some with a half-life of up to 373.59 days. Therefore this ruthenium has to be stored at least for 10 years in a secured area to allow it to become stable. Fission-derived Ruthenium has a specific activity of 8.1 curies of radioactivity per gram. Under health physics safety rules any isotope that emits more than 1 ci of activity is a hazard; however, after 6 years the activity falls to 4.1 ci, after 7 years it is 2.2, after 8 years 1.1, after 9 years .55 ci and after 10 years only .27 ci. After 20 years the activity falls to 2.702E-4 ci, which is under the threshold for low level risk by even the most stringent health physics rules.

Adapted from the Wikipedia article "Occurrence", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki