Osmium Mining

Osmium is one of the rare earth metal found in the earth's crust. It is mostly obtained as a byproduct during mining of copper and nickel minerals. It is found mostly as an uncombined element or as a natural alloy with iridium. Mining and extracting of osmium are done in nickel and copper deposits of countries such as Russia, Canada, China, South Africa, Japan, Oman, United States, Brazil, Australia and India etc..

The mining of osmium comprising ore are done with open pit mining. During the mining process of the nickel and copper minerals, osmium occurs as a minimal product along other platinum group minerals such as ruthenium, iridium and palladium in the form of sulfides (XS), telluride (XBiTe), antimonides (XSb) and arsenide (XAs_2). (Here 'X' denotes the elements from platinum group.)

Extraction of osmium:

The separation and extraction of osmium from the ores of copper and nickel will be a tedious process. At first the ores are made to electro-refining process in which the noble metals such as gold, silver, platinum, osmium, iridium, ruthenium and non metals such as selenium and tellurium will be settle down at the anode mud of the cell. The anode mud makes up the primary material of extraction.

For the further separation process the mud is made into a solution by mixing them with sodium peroxide. Then the fused mixture is made to dissolute in aqua regia or chlorine with hydrochloric acid based on the composition of the mixture. The inability to dissolve in the aqua regia by osmium, ruthenium, iridium and rhodium separates them from gold, platinum and other non metals as a solid residue mixture. It is treated with sodium bisulfate to separate rhodium from the mixture.

Now the mixture remains of insoluble osmium-ruthenium-iridium composite. For the separation of iridium, it is treated with sodium oxide where the iridium remains insoluble by producing water soluble osmium-ruthenium salts. The salts are made to undergo oxidization with volatile oxides from which RuO_4is separated from OsO_4 by using (NH_4 )_3 RuCl_6 precipitation withNH_4 Cl.

Separation of osmium:

Finally the osmium is separated from other platinum groups by distillation or dissolving them in the volatile organic solvent of osmium tetroxide. The final product is then reduced by hydrogen to form metal powder or sponges which are later treated with powder metallurgical techniques for a quality output. This is the industrial method for extraction and production of osmium.

The largest known reserves to extract osmium are Bushveld Igneous Complex in South Africa, Norsik reserve in Russia, Sudbry Basin in Canada and some alluvial deposits such as Choc? Department in Columbia and Ural mountain deposits in Russia. Apart from this it is mined over 20 countries around the world with the global production of 1000 kg per year.

Osmium:

Osmium is one of the rare earth metal found in the earth's crust. It is mostly obtained as a byproduct during mining of copper and nickel minerals. It is found mostly as an uncombined element or as a natural alloy with iridium. Mining and extracting of osmium are done in nickel and copper deposits of countries such as Russia, Canada, China, South Africa, Japan, Oman, United States, Brazil, Australia and India etc..

Mining Process:

During the mining processof the nickel and copper minerals, osmium occurs as a minimal product along other platinum group minerals such as ruthenium, iridium and palladium in the form of sulfides (XS), telluride (XBiTe), antimonides (XSb) and arsenide (XAs_2).(Here 'X' denotes the elements from platinum group.)

separation and extraction:

The separation and extraction of osmium from the ores of copper and nickel will be a tedious process. At first the ores are made to electro-refining process in which the noble metals such as gold, silver, platinum, osmium, iridium, ruthenium and non metals such as selenium and tellurium will be settle down at the anode mud of the cell. The anode mud makes up the primary material of extraction. For the further separation process the mud is made into a solution by mixing them with sodium peroxide. Then the fused mixture is made to dissolute in aqua regia or chlorine with hydrochloric acid based on the composition of the mixture. The inability to dissolve in the aqua regia by osmium, ruthenium, iridium and rhodium separates them from gold, platinum and other non metals as a solid residue mixture. It is treated with sodium bisulfate to separate rhodium from the mixture. Now the mixture remains of insoluble osmium-ruthenium-iridium composite. For the separation of iridium, it is treated with sodium oxide where the iridium remains insoluble by producing water soluble osmium-ruthenium salts. The salts are made to undergo oxidization with volatile oxides from which RuO_4is separated from OsO_4 by using (NH_4 )_3 RuCl_6 precipitation withNH_4 Cl.

Finally the osmium is separated from other platinum groups by distillation or dissolving them in the volatile organic solvent of osmium tetroxide. The final product is then reduced by hydrogen to form metal powder or sponges which are later treated with powder metallurgical techniques for a quality output. This is the industrial method for extraction and production of osmium.

The largest known reserves to extract osmium are Bushveld Igneous Complex in South Africa, Norsik reserve in Russia, Sudbry Basin in Canada and some alluvial deposits such as Choc? Department in Columbia and Ural mountain deposits in Russia. Apart from this it is mined over 20 countries around the world with the global production of 1000 kg per year.

Applications:

Because of the instability and extreme toxicity of its oxide, osmium is not often used in its pure state, and is instead often alloyed with other metals. Those alloys are utilized in high-wear applications. Osmium alloys such as osmiridium are very hard and, along with other platinum group metals, are used in the tips of fountain pens, instrument pivots, and electrical contacts, as they can resist wear from frequent operation.

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