Tantalum

Tantalum

Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalium, the name comes from Tantalus, a character from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion resistant. It is part of the refractory metals group, which are widely used as minor components 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 capacitors in electronic equipment such as mobile phones, DVD players, video game systems and computers. Tantalum, always together with the chemically similar niobium, occurs in the minerals tantalite, columbite and coltan (a mix of columbite and tantalite).

Occurrence

Tantalum is estimated to make up about 1 ppm or 2 ppm of the Earth's crust by weight. There are many species of tantalum minerals, only some of which are so far being used by industry as raw materials: tantalite, microlite, wodginite, euxenite, polycrase. Tantalite (Fe, Mn)Ta2O6 is the most important mineral for tantalum extraction. Tantalite has the same mineral structure as columbite (Fe, Mn) (Ta, Nb)2O6; when there is more Ta than Nb it is called tantalite and when there is more Nb than Ta is it called columbite (or niobite). The high density of tantalite and other tantalum containing minerals makes the use of gravitational separation the best method. Other minerals include samarskite and fergusonite.

The primary mining of tantalum is in Australia, where the largest producer, Global Advanced Metals, formerly known as Talison Minerals, operates two mines in Western Australia, Greenbushes in the Southwest and Wodgina in the Pilbara region. The Wodgina mine was reopened in January 2011 after mining at the site was suspended in late-2008 due to the global financial crisis. Less than a year after it reopened, Global Advanced Metals announced that due to again "... softening tantalum demand ...", and other factors, tantalum mining operations were to cease at the end of February 2012. Wodgina produces a primary tantalum concentrate which is further upgraded at the Greenbushes operation before being sold to customers. Whereas the large-scale producers of niobium are in Brazil and Canada, the ore there also yields a small percentage of tantalum. Some other countries such as China, Ethiopia, and Mozambique mine ores with a higher percentage of tantalum, and they produce a significant percentage of the world's output of it. Tantalum is also produced in Thailand and Malaysia as a by-product of the tin mining there. During gravitational separation of the ores from placer deposits, not only is Cassiterite (SnO2) found, but a small percentage of tantalite also included. The slag from the tin smelters then contains economically useful amounts of tantalum, which is leached from the slag. Future sources of supply of tantalum, in order of estimated size, are being explored in Saudi Arabia, Egypt, Greenland, China, Mozambique, Canada, Australia, the United States, Finland, and Brazil.

Coltan, the industrial name for a columbite–tantalite mineral from which columbium (i.e. niobium) and tantalum are extracted, can also be found in Central Africa, which is why tantalum is being linked to warfare in the Democratic Republic of the Congo (formerly Zaire). According to an October 23, 2003 United Nations report, the smuggling and exportation of coltan has helped fuel the war in the Congo, a crisis that has resulted in approximately 5.4 million deaths since 1998 – making it the world’s deadliest documented conflict since World War II. Ethical questions have been raised about responsible corporate behavior, human rights, and endangering wildlife, due to the exploitation of resources such as coltan in the armed conflict regions of the Congo Basin. However, although important for the local economy in Congo, the contribution of coltan mining in Congo to the world supply of tantalum is usually small. The United States Geological Survey reports in its yearbook that this region produced a little less than 1% of the world's tantalum output in 2002–2006, peaking at 10% in 2000 and 2008.

It is estimated that there is less than 50 years left of Tantalum resources, based on extraction at current rates, demonstrating the need for increased recycling.

Symbol		Ta
Atomic Number		73
Atomic Weight		180.9479
Oxidation States		+5
Electronegativity, Pauling		2.36
State at RT		solid
Melting Point, K		3269
Boiling Point, K		5698

Appearance and Characteristics

Harmful effects:

Tantalum is considered to be non-toxic.

Characteristics:

• Tantalum is a rare, shiny, gray, dense metal. It is highly ductile and can be drawn into a thin wire.
• Its chemical properties are very similar to those of niobium. Tantalum is highly corrosion resistant due to the formation of an oxide film. It is an excellent conductor of heat and electricity.
• The metal has a melting point exceeded only by tungsten and rhenium. Tantalum is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refractory metals are tungsten, molybdenum, rhenium and niobium.

Uses of Tantalum

• Tantalum is used in the electronics industry for capacitors and high power resistors.
• It is also used to make alloys to increase strength, ductility and corrosion resistance.
• The metal is used in dental and surgical instruments and implants, as it causes no immune response.