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Niobium treated with sodium hydroxide forms a porous layer that aids osseointegration. [109] Like titanium, tantalum, and aluminium, niobium can be heated and anodized ("reactive metal anodization") to produce a wide array of iridescent colours for jewelry, [110] [111] where its hypoallergenic property is highly desirable. [112]
Tantalite (Fe, Mn)Ta 2 O 6 is the most important mineral for tantalum extraction. Tantalite has the same mineral structure as columbite (Fe, Mn) (Ta, Nb) 2 O 6; when there is more tantalum than niobium it is called tantalite and when there is more niobium than tantalum is it called columbite (or niobite).
The mineral group tantalite [(Fe, Mn)Ta 2 O 6] is the primary source of the chemical element tantalum, a corrosion (heat and acid) resistant metal. It is chemically similar to columbite , and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides.
Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original American name columbium), and the tantalum-dominant mineral is tantalite. [1] Tantalum from coltan is ...
Apollo CSM with the dark rocket nozzle made from niobium-titanium alloy . Niobium is nearly always found together with tantalum, and was named after Niobe, the daughter of the mythical Greek king Tantalus for whom tantalum was named. Niobium has many uses, some of which it shares with other refractory metals.
In 1809, English chemist William Hyde Wollaston compared the oxides derived from both columbium—columbite, with a density 5.918 g/cm 3, and tantalum—tantalite, with a density over 8 g/cm 3, and concluded that the two oxides, despite the significant difference in density, were identical; thus he kept the name tantalum. [14]
Tantalum ores often contain significant amounts of niobium, which is itself a valuable metal.As such, both metals are extracted so that they may be sold. The overall process is one of hydrometallurgy and begins with a leaching step; in which the ore is treated with hydrofluoric acid and sulfuric acid to produce water-soluble hydrogen fluorides, such as the heptafluorotantalate.
In 1846, Heinrich Rose discovered that tantalite contained an element similar to tantalum and named it niobium. [7] [8] In the 1860s, it was found that niobium and columbium are the same element and are distinct from tantalum. [9] IUPAC officially adopted niobium in 1950 after 100 years of controversy. [10]