Short answers, pulled from the story.
Tantalum is a chemical element with symbol Ta and atomic number 73. Its largest commercial use is in tantalum electrolytic capacitors for electronic devices such as smartphones, personal computers, and cameras. It is also used for surgical implants, aerospace shielding on spacecraft such as Voyager 1 and Voyager 2, alloys for jet engine components, and is being investigated for superconducting resonators in quantum processors.
Tantalum was discovered by the Swedish chemist Anders Ekeberg in 1802, from two mineral samples - one from Sweden and one from Finland. Ekeberg named the element after Tantalus, a figure from Greek mythology, partly because of tantalum's inability to absorb acid when immersed in it.
Tantalum is linked to armed conflict through coltan, a mineral from which tantalum is extracted and which is mined in Central Africa. A United Nations report from the 23rd of October, 2003 found that coltan smuggling helped fuel the war in the Democratic Republic of the Congo, a conflict that caused approximately 5.4 million deaths since 1998. As of January 2021 USGS data, close to 40% of global tantalum mine production came from the Democratic Republic of the Congo.
Tantalum forms a lasting and durable structural bond with human hard tissue, making it uniquely suited for bone and dental implants. It is also non-ferrous and non-magnetic, so patients with tantalum implants can safely undergo MRI procedures. Tantalum coatings are applied to titanium surgical implants to provide a biologically stable bond with hard tissue.
Tantalum and niobium have nearly identical chemical properties, making their separation one of the most demanding processes in industrial metallurgy. The standard approach is hydrometallurgy: dissolving the ore in hydrofluoric acid with sulfuric or hydrochloric acid, then selectively extracting tantalum. The two elements are finally separated by lowering the ionic strength of the acid mixture, which causes niobium to dissolve in the aqueous phase while tantalum remains in the organic solvent.
Tantalum has a melting point of 3017 degrees Celsius and a boiling point of 5458 degrees Celsius. Among metals, only tungsten, rhenium, and osmium have higher melting points. This extreme heat resistance places tantalum in the refractory metals group and makes it valuable for vacuum furnace parts, jet engine superalloys, and other high-temperature applications.