Wednesday, June 4, 2014

Tantalum: The Newest Precious Metal?


Given that the advent of the smart phone, mobile phone and tablet computer boom a few years ago now made tantalum more expensive than silver – does this mean that tantalum is the newest precious metal?

By: Ringo Bones

Even though it has been in use in high performance electronic gear since the technological boom of the 1960s, it is only when the massive demand for mobile phones, smart phones and tablet computers a few years ago has finally made tantalum more expensive than silver making it the newest addition to the precious metals family. Chemical symbol Ta, atomic number 73, tantalum is a metallic chemical element. It is a member of the vanadium family which includes niobium and vanadium. Tantalum was discovered in 1802 by Anders Gustav Ekeberg and an ultrapure specimen was finally purified by Swedish chemist Jöns Jakob Berzelius in 1820. 

The name of the element is derived from Greek mythology: King Tantalus, the son of Zeus, was punished by being placed in a pool in which the level of water receded from him each time he tried to drink; the name of the element is thus symbolic of the difficulty encountered in its isolation that lead to the discovery of the element. Tantalum is freed from its various ores by caustic or by potassium monosulfate fusion followed by water extraction to give the water soluble solution. 

During the technological boom of the 1960s, the principal source of tantalum is iron tantalite which is chemically similar to the mineral columbite. In the 1960s, the African country then known as Rhodesia – which since 1980 has been renamed Zimbabwe when Robert Mugabe took over when it became independent from the UK – produces about 70 percent of the world’s supply of the metal. But since the 21st Century mobile phone, smart phone and tablet computer boom, virtually all tantalum produced today are sourced from the mineral coltan which is, unfortunately, mined in conflict zones in Africa by warlords to underwrite their various military adventurism in the Democratic Republic of Congo, Sierra Leone and neighboring countries - as in classified as a "conflict mineral" by the United Nations and the World Trade Organization.

Tantalum is a white metal, remarkably ductile, malleable, strong and tough. It has a melting point of 3,100 degrees Celsius and a boiling point of 6,000 degrees Celsius and a density of 16.69 grams per cubic centimeter. Tantalum resists the action of acids, including the one capable of dissolving gold called aqua regia - which is a mixture of nitric acid and hydrochloric acid, but tantalum can be dissolved by a mixture of nitric acid and hydrofluoric acid.  

Tantalum is used to make dental and surgical instruments, corrosion-resistant equipment, electrodes, rectifiers, pens, receptacles, tubes and other chemical-engineering devices are readily formed for use in reactions utilizing corrosive vapors and liquids and in vacuum furnace parts. In the electronics industry, those ultra-compact acid electrolyte tantalum electrolytic capacitors which are 20 times smaller than aluminum electrolytic capacitors of the same capacitance value and working voltage and pulsating direct current is obtained from alternating current by the use of tantalum-lead-sulfuric-acid-rectifier and electric-lamp filaments.

Other electrical and electronic uses of tantalum is the World War I era tantalum alloy rechargeable batteries that made the company who made it - Tannoy - famous the world over, though these days, Tannoy is more famous as a high-quality Scotland based hi-fi loudspeaker manufacturer than a World War I era rechargeable battery manufacturer. In addition, tantalum is used as an alloying element with both steel and tungsten and in standard weights. Tantalum carbide is a very hard substance that’s used for drill points and other cutting devices. 

Almost impervious to corrosion, tantalum is vital in surgical repairs of the human body: it can replace bone – for example in skull plates – as foil or wire, tantalum connects torn nerves. Used as woven gauze, tantalum binds up abdominal muscles. Tantalum’s good thermal conductivity give it utility in the production of surgical splints, screws, nails, sheets, gauze, plates, etc. for use in internal body repair. 

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