Tantalum

Tantalum is a chemical element with the symbol Ta and atomic number 73. It is a blue-grey metal that is dense and notably resistant to corrosion at room temperature. It belongs to the group of metals known as refractory metals, meaning they have extremely high melting points—around 3000 degrees Celsius.

Tantalum does not occur in nature in pure form; it is extracted from ores such as tantalite and columbite. The ore mixture containing both tantalum and niobium is commonly known as coltan. Processing is complicated by the need to separate tantalum and niobium, since the two elements have very similar chemical properties.

Physical and chemical properties

When tantalum is exposed to air, a thin oxide layer (tantalum pentoxide) forms on its surface. This layer protects the metal from corrosion, making tantalum highly resistant to most ordinary corrosive environments. The oxide layer also has dielectric properties, which is the basis for its most important application.

Applications

The largest application is in tantalum capacitors—small components that store electrical charge and are found in mobile phones, computers, and medical devices. They are notable for storing significant power in a small space. Tantalum is also used in corrosion-resistant chemical equipment, high-temperature furnace components, and aircraft engine alloys. Because the human body does not react to it, it is used in medical devices such as bone plates and pacemakers.

Production and market issues

Tantalum production is concentrated in a small number of countries. Some coltan ore comes from central Africa, particularly from the Democratic Republic of the Congo and neighboring countries, where its trade has been linked to the financing of armed groups. This has led to international regulations requiring companies to disclose the origin of ore ('conflict minerals'). Other significant producers include Brazil, Australia, and Rwanda. Refineries also depend on recycling tantalum from discarded electronics.

History of the name

The element was discovered in the early 19th century and was named after Tantalus, a figure from ancient Greek mythology. For a long time, chemists were confused about tantalum and niobium, and they were thought to be the same element until they were shown to be distinct.