Cobalt: From Magnets to Medicine

Cobalt compounds were first used centuries ago to impart a distinctive blue color to glass, glazes and ceramics.  Egyptian sculptures, Persian jewelry from the third millennium BC, objects from the Pompeii ruins and in China’s Tang and Ming dynasties all show evidence of cobalt.  Cobalt glass ingots have been recovered from shipwrecks from the Minoan era.

Today, cobalt salts are still used for the production of brilliant and permanent blue colors in paint pigments, porcelain, glass, pottery, tiles, and enamels.

But cobalt applications go far beyond aesthetics.  It is a strategic and critical metal used in many diverse commercial, industrial, and military applications.  Nearly one-half of cobalt consumed in the U.S. are used in superalloys, which, in turn, are used to make parts for gas turbine aircraft engines.   Alloyed with iron, nickel and other metals it is used to make Alnico, an alloy of unusual magnetic strength with essential uses in jet and gas turbine engines.

In medicine, Cobalt-60, an artificially-produced radioactive isotope of the element, is an important radioactive tracer and radiotherapeutic cancer-treatment agent.

Cobalt-60  is also valuable in industry, as a gamma ray source, because it can be produced in predictable quantity by simply exposing natural cobalt to neutrons in a reactor for a given time. It is used in applications like medical sterilization, cold pasteurization, weld integrity radiographs and concrete density measurements.

Cobalt is also used in the preparation of magnetic, high-strength and corrosion- and wear-resistant alloys; high-speed steels; cemented carbides (hardmetals) and diamond tools; as catalysts in the petroleum and chemical industries; drying agents for paints, varnishes, and inks; ground coats for porcelain enamels; lithium-ion battery electrodes; steel-belted radial tires; and magnetic recording media.  It is used in electroplating because of its appearance, hardness, and resistance to oxidation.

The United States does not currently mine or refine cobalt.  Over 80% of our cobalt is imported; the remainder is contained in purchased scrap that is recycled.  The Democratic Republic of the Congo is the world’s top producer of cobalt with almost 40% world share. The U.S. uses about 11,300 metric tonnes of cobalt each year; Birch Lake would product 2.9 million pounds.