Discovered in 1778 by Carl Wilhelm Scheele, Molybdenum is a chemical element with symbol Mo and atomic number 42. Its name is derived from the Neo-Latin molybdaenum, and Ancient Greek molybdos, both meaning lead, as the element was originally found in a mineral known as molybdenite which had been confused for a lead compound. It is not a naturally occurring free metal, but rather materialises in various oxidation states in minerals. It is the 42nd most abundant element in the Universe and the 54th most abundant element in the Earth’s crust.
For about a century after its isolation, Molybdenum had no industrial use owing to the difficulty of extracting it. It was not until 1913 that Frank E. Elmore developed a froth flotation process to recover molybdenite from ores, which is still the primary isolation process today.
Molybdenum has the sixth highest melting point of any element and is used to make the electrodes for electrically heated glass furnaces, as well as some electrical filaments. This property makes it incredibly versatile. Its ability to withstand temperatures without significantly expanding makes it useful in the manufacture of armour, aircraft parts and industrial motors too. Some steels which have additions of molybdenum can withstand pressures of up to 300,000 pounds per square inch.
The primary metallurgical use of Molybdenum is as an alloying agent in steel. It has many properties and is used to make steels for a wide range of applications for example construction, earth moving, automotive and marine. The HSLA.grades have perhaps the lowest levels of molybdenum often less than 1% however additions of up to 9% are found in the “M” series range of high speed steels. It is often alloyed with Nickel and chromium to form heat and corrosion resistant materials used in the chemical industry. Molybdenum is also present in cutlery grades like 440C and in tool steels where it helps improve wear resistance and hardness.
In addition to its commercial uses, Molybdenum is also an essential trace element and crucial to the survival of lifeforms. It functions as a cofactor for a number of enzymes that catalyse important chemical transformations in the global carbon, nitrogen and sulphur cycles. The human body contains 0.07 mg of Molybdenum per kilogram of weight and it is also present in tooth enamel, helping to prevent decay.
William Rowland is the UK appointed sales agent and distributor for the Kennecott Molybdenum Company.