Tantalum
Tantalum is a chemical element with the symbol Ta and atomic number 73. A rare, hard, blue-grey, lustrous transition metal, tantalum is highly corrosion-resistant and occurs naturally in the mineral tantalite, always together with the chemically similar niobium. It is part of the refractory metals group, which are widely used as minor component in alloys. The chemical inertness of tantalum makes it a valuable substance for laboratory equipment and a substitute for platinum, but its main use today is in tantalum electrolytic capacitors.
Several steps are involved in the extraction of tantalum from tantalite. First the mineral is crushed and concentrated by gravity separation. This is generally carried out near the mine site. Further processing by chemical separation is usually done by treating the ores with a mixture of hydrofluoric acid and sulfuric acid at over 90°C. This causes the tantalum and niobium to dissolve as complex fluorides and be separated from the impurities.
The major use for tantalum, as the metal powder, is in the production of electronic components, mainly capacitors and some high-power resistors. Tantalum electrolytic capacitors exploit the tendency of tantalum to form a protective oxide surface layer, using tantalum powder, pressed into a pellet shape, as one "plate" of the capacitor, the oxide as the dielectric, and an electrolytic solution or conductive solid as the other "plate".
Tantalum is highly bio compatible and is used for body implants and coatings, therefore attention may be focused on other elements or the physical nature of the chemical compound |
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