Rhenium: a rare metal critical in modern transportation

Abstract

Rhenium is a silvery-white, metallic element with an extremely high melting point (3,180 degrees Celsius) and a heat-stable crystalline structure, making it exceptionally resistant to heat and wear. Since the late 1980s, rhenium has been critical for superalloys used in turbine blades and in catalysts used to produce lead-free gasoline. One of the rarest elements, rhenium has an average abundance of less than one part per billion in the continental crust. Rhenium was the last stable, naturally occurring element discovered. Although its existence was predicted in 1871—Russian chemist Dmitri Mendeleev noted two vacant slots below manganese on the periodic table of elements—rhenium was not isolated until 1925, when German chemists Walker Noddack, Ida Tacke, and Otto Berg detected it in platinum ore. Rhenium rarely occurs as a native element or as its own sulfide mineral—rheniite (ReS 2 )—and often occurs as a substitute for molybdenum in molybdenite (MoS 2 ). Most extracted rhenium is a byproduct of copper mining, with about 80 percent recovered from flue dust during the processing of molybdenite concentrates from porphyry copper deposits.