Osmium-chemistry » Display

The production of osmium is very complex and usually takes place during the extraction of other metals, such as platinum or gold.

The reactant for osmium extraction is usually the anode slime from gold or nickel production. The anode slime is dissolved in aqua regia, which causes platinum and gold to dissolve. The other platinum metals and silver remain.

The silver forms insoluble silver chloride, which can be separated using nitric acid and lead carbonate. It is then melted with sodium bicarbonate and leached out.

Thus, rhodium is dissolved as rhodium sulfate and removed. The residue is melted down together with sodium peroxide, resulting in ruthenium and osmium going into solution. Iridium remains in the insoluble residue.

Chlorine is added to the solution. This produces the volatile substances osmium tetroxide and ruthenium tetroxide.

After the addition of alcoholic sodium hydroxide solution, only osmium tetroxide goes into solution and can thus be separated from the ruthenium tetroxide.

To obtain elemental osmium, it is precipitated with ammonium chloride as a complex.

Finally, it is reduced with hydrogen to metallic osmium.

_OsO2(_NH3)4Cl2+ 3 _H2 → Os + 4 ^NH4+ + 2 ^Cl- + 2 ^OH-