Molybdenum (Mo) is the 42nd element on the periodic table. It is a silvery metal and has the sixth highest melting point of any elements, demonstrating its potential uses in construction and metals.
Molybdenum was discovered by Carl Welhelm Scheele, a Swedish chemist, in 1778 in a mineral known as molybdenite (MoS2) which had been confused as a lead compound. Molybdenum was isolated by Peter Jacob Hjelm in 1781. Today, most molybdenum is obtained from molybdenite, wulfenite (PbMoO4) and powellite (CaMoO4). These ores typically occur in conjunction with ores of tin and tungsten. Molybdenum is also obtained as a byproduct of mining and processing tungsten and copper.
There was no viable use of Molybdenum for over a century. This was due to its scarcity and difficulty in acquiring and extracting the pure element. Early molybdenum steel alloys showed great promise in their increased hardness, but efforts to manufacture them on a large scale were hampered by inconsistent results and a tendency toward brittleness and recrystallization. In 1913, Frank E. Elmore developed a flotation process to recover molybdenite from ores; flotation remains the primary isolation process today.
It started to become useful during war times where its strength to weight ratio far exceeded anything else on the market. During World War One, demand for Molybdenum increased dramatically. Molybdenum was used as armor plating for tanks (up to 3” thick molybdenum sheet) and other military vehicles and also as a substitute for tungsten in high speed steels. After the war, its demand dropped and it wasn't until World War Two where it again played another important role. But the use of molybdenum has expanded to various new uses as technology has developed and it now plays a critical role in construction and even in agriculture.
Molybdenum disulphide (MoS2), one of molybdenum's compounds, is used as a high temperature lubricant. Molybdenum trioxide (MoO3), another molybdenum compound, is used to adhere enamels to metals. Other molybdenum compounds include: molybdic acid (H2MoO4), molybdenum hexafluoride (MoF6) and molybdenum phosphide (MoP2).
To break down how molybdenum is approximately used:
37% is used to create construction grade steel.
22% is used in the manufacturing of stainless steel.
15% is used in chemicals such as lubricant grade MoS2.
9% is used in the creation of tool and high-speed steels.
7% goes towards cast iron.
6% in Molybdenum Metal.
4% towards super alloys.
Molybdenum is primarily used as an alloying agent in steel. When added to steel in concentrations between 0.25% and 8%, molybdenum forms ultra-high strength steels that can withstand pressures up to 300,000 pounds per square inch. Molybdenum also improves the strength of steel at high temperatures. When alloyed with nickel, molybdenum forms heat and corrosion resistant materials used in the chemical industry.
In 1906, William D. Coolidge filed a patent for rendering molybdenum ductile, leading to use as a heating element (molybdenum rod) and as shields (molybdenum sheet) for high-temperature furnaces.. Molybdenum sheet also has use in the manufacturing missile and aircraft parts as well as used in the nuclear power industry. Molybdenum is also used as a catalyst in the refining of petroleum.
Molybdenum has the ability to withstand extremely high temperatures without its shape changing, expanding or softening significantly. This ability makes its involvement in high heat situations very useful. It is used in manufacturing of armor, aircraft parts, industrial motors, filaments and electrical contacts. When considering high strength steel alloys, it should be noted that they typically contain between 0.25% and 8% molybdenum.
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