Ruthenium Mining

Ruthenium is a rare metal occurs about 0.001ppm on the earth's crust. It occurs in natural alloys with other noble metals in iridosmine (14.1% Ruthenium ) and siserskite (18% ruthenium) and as many natural isotopes.

Mining:

The ruthenium found in natural alloys cannot be used for the commercial production of ruthenium. Ruthenium can only be extracted from the ores of copper sulfide and nickel as it contains ruthenium and other platinum group metals as impurities. Ruthenium is mined and extracted in the byproduct mines of copper and nickel as byproduct.

The copper and nickel ore with ruthenium are mined by both surface and underground mining. The chalcocite and chalcopyrite are the major ores which are mined mostly for extracting ruthenium.

In surface mining, open pit mining is followed by step down benching process where the mines drilled and blasted. The open pit mining is less expensive in ruthenium mining and is widely executed.

The underground mining is used in areas where the ores happens to be deep inside the earth's surface. It is an expensive process which is done only in the areas of high quality ores. Less wastage and health risks are the pros of underground mining. This method of ruthenium mining is employed in a small scale.

The major ruthenium containing ores are pentlandite in Sudbury, Ontario at Canada and pyroxenite in South Africa.

Processing and extraction:

The collected ores of copper and nickel bearing ruthenium are milled and crushed into small particles. Then the crushed small particles are collected as gangue and undergo roasting, smelting and electrolytic refining to discard impurities from it. During the electrolytic refining, the noble metals such as gold, silver, platinum, osmium, ruthenium, iridium, rhodium and non metals such as selenium and tellurium are the impurities which settles down as anode mud inside the electrolytic cell. The collected anode mud is the initial component for ruthenium production. The anode mud is made to a liquid solution by adding sodium peroxide (Na2O2) with it.

Then the mixture dissolved in aqua regia or chlorine with concentrated hydrochloric acid, in which the usage scale for acid is based on the composition of anode mud mixture. After executing the mixing step; gold, platinum and other non metals will be dissolved in the concentrated acid mixture leaving ruthenium, osmium, iridium and rhodium as a solid residue within it. The solid residue is now treated with sodium bisulfate (NaHSO4) to discard rhodium from the mixture.

Now the mixture remains of insoluble osmium-ruthenium-Iridium composite which is treated with sodium oxide where the Iridium remains insoluble by producing water soluble osmium-ruthenium salts. Then the immiscible Iridium solution separated from the osmium- ruthenium slats by liquid-liquid extraction. The salts are oxidized to RuO4 and OsO4. Then ruthenium is isolated from osmium tetroxide by reacting or dissolution with ammonium chloride and organic solvents creating a precipitate (NH4)3RuCl6.

Later, the resulted precipitate is reduced by hydrogen to produce ruthenium metal as sponge. The sponges are crushed and made into pure metal powder by powder metallurgical techniques.Ruthenium can also be produced by nuclear transmutation of technetium isotope in the laboratory.The major ruthenium producing countries are South Africa, Russia and Canada

Definition:

Ruthenium is a chemical component that has the symbol Ru and atomic number 44. A rare changeover metal of the platinum group of the periodic table, ruthenium is found connected with platinum ores and used as a catalyst in some platinum alloys.

Properties:

Ruthenium has four crystal modifications and does not dull at normal temperatures, but does oxidize eagerly on exposure to air to form ruthenium tetroxide, RuO4, a strong oxidising agent with properties analogous to those of osmium tetroxide. Ruthenium dissolves in fused alkalis, is not attacked by acids but is attacked by halogens at high temperatures.