Properties and Applications

electric devices routerboard © potsawat / Fotolia.comelectric devices routerboard © potsawat / Fotolia.comPlatinum is a very corrosion-resistant precious metal that is used for manufacture of jewelry, automobile catalysts, laboratory equipment, dental implants, and materials for electrical contacts. Platinum in the form of wires, metal sheets or tubes is processed for manufacture of electrical switching contacts, heating elements or thermocouples. Due to its high melting temperature and corrosion resistance it is used for fabricating medical and technical appliances such as dishes, crucibles, wires or metal sheets. Jewelry platinum, the second most important sales market for platinum, consists of 96 % platinum with 4 % copper or sometimes 90 % platinum with 10 % palladium alloys and is most often used for manufacture of clockworks and jewelry mountings. Besides, platinum is also used in medicine. Cancer therapy mainly uses cis-platinum (diammine-dichloro-platinum; DDP, a complex-bound platinum atom). Like all cancer drugs, Cis-Platin has a toxic effect also on healthy cells.

Besides, it does not form oxide or sulfide surface layers as, for example, sterling cutlery or silver jewelry after a certain time. The chemical behavior of platinum is contradictory: On the one hand, it behaves like a precious metal that cannot be destroyed by most of the simple chemicals, on the other hand, it may be highly reactive, for example if particles are very small. At high temperatures, platinum is extremely durable.

For all these reasons, platinum is of interest mainly to industrial applications. With almost 60 % of the worldwide platinum demand, emphasis is on the use of platinum nanoparticles in catalytic converters. In today’s widespread three-way catalytic converters, platinum converts carbon monoxide into carbon dioxide, hydrocarbons into carbon dioxide, and nitric oxides into nitrogen. In addition, the catalytic properties of platinum nanoparticles are used for nitric acid manufacture and numerous other processes e.g., production of fuel cells with nano platinum as electrode material.

 

Platinum is not self-igniting. The mixture of platinum with air (dust) is also non-flammable under the influence of an ignition source, so there is no possibility of adust explosion.

 

Occurrence and Production

Platinum, which occurs in the pure metallic form in nature, is hardly mined anymore. There are some mines left in South Africa which with an annual output of 150 tons is the by-far largest producer. Further mines are found in Russia (25 t/year) and Canada (8 t/year). Production of the non-ferrous metals copper and nickel leaves platinum group metals (palladium, rhodium, iridium, osmium, ruthenium) as by-products and, thus, is yet another major source for platinum. Since these five metals have a very similar chemical behavior, separation is a rather difficult process. Mostly, the different solubilities of platinum salts are used in different solvents (solvent extraction). Relatively pure platinum which occurs in the form of nanoscale powder or platinum sponge is obtained by simple heating.

 

Literature arrow down

  1. Gmelins Handbuch der anorganischen Chemie, 8. Auflage, Leipzig.
  2. Chen, A et al. (2010), Chem Rev, 110(6): 3767-3804.
  3. Daunderer, M (24.10.2007). Handbuch der Umweltgifte, Ausgabe 6/2006.
  4. Sures, B & Zimmemann, S (2005). Untersuchungen zur Toxizität der Platingruppenelemente Pt, Pd und Rh, Abschlussbericht, FKZ BWR 22012, Landesanstalt für Umwelt, Messungen und Naturschutz, Baden-Wuerttemberg (LUBW).

 

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