This is an updated version of an article first published on Manganese Investing News on June 13, 2013.
For many investors, manganese may not be a familiar element. However, it’s one of the top four metals used in the world, behind only iron, aluminum and copper. It’s also the world’s fifth-most abundant metal.
Manganese is primarily used to improve the properties of other metals in alloys, with about 90 percent of mined material going towards steel production. Unfortunately, as the International Manganese Institute states in an August 2015 report, the recent decline in steel production has also meant decreases in manganese production around the world.
Manganese uses: steelmaking
As mentioned, the majority of manganese is used as an alloying element in steel. While steel itself is an alloy of iron and carbon, manganese plays a key role in steelmaking because of its ability to combine with sulfur; it is also valued for its powerful deoxidation capacity. When manganese is added to molten steel, it increases the alloy’s strength and makes it more resistant to impact.
At room temperature, iron crystallizes into a cubic structure known as ferrite. At high temperatures above 1,670 degrees Fahrenheit, it then transforms into a cubic form called an austenite. As the steel is slowly cooled down, the carbon within the steel becomes a separate solid called cementite; the austenite then changes back to ferrite, and the two combine to become pearlite.
Manganese is used to lower the temperature at which ferrite is formed. That causes cementite to form at a higher temperature, thereby refining the pearlite. Because the strength and toughness of the resulting steel depends on the integrity of the pearlite, manganese is an extremely important factor in the manufacturing of steel.
Manganese is also used at other points in the steelmaking process. When forged, crude steel contains too much oxygen, as well as some sulfur. Manganese is an essential addition to the forging process because it has a powerful deoxidation capacity and it can combine with sulfur, solving both forging issues.
Today, the majority of multipurpose, low-carbon steel is made up of between 0.15 and 0.8 percent manganese. High-strength steels — those that require a yield strength over 500 megapascals — may contain over 1 percent manganese. While these only represent 3 to 4 percent of the tonnage of steel produced, much of it is high-strength, low-alloy steel. When steel needs to have a very fine ferrite structure, sometimes low-carbon, controlled-rolled steel is produced that contains up to 1.8 percent manganese. The micro-alloying additions strengthen the steel, and it is widely used in oil or gas pipelines, for shipbuilding and in other transportation equipment to help reduce weight.
Because of manganese’s specific qualities, there are no satisfactory substitutes for it in steelmaking.
Manganese uses: batteries
Manganese’s main non-metallurgical application is as manganese dioxide, which is a depolarizer in dry-cell batteries. Manganese dioxide essentially acts as a dehumidifier in the over 20 billion dry-cell units produced every year. Many are familiar with alkaline batteries, the most common battery, although some may not realize they contain manganese dioxide as a key ingredient.
Then there are lithium-manganese-oxide batteries, also commonly called lithium-manganate or lithium-ion-manganese batteries, or li-manganese or spinel. The technology for this type of battery was first discovered in the 1980s, with the first publication on the subject appearing in the Materials Research Bulletin in 1983. The first commercial lithium-ion cell made with a lithium-manganese-oxide as a cathode material was produced in 1996 by Moli Energy.
Lithium-manganese-oxide batteries are notable for their high thermal stability and are also safer than other types of lithium-ion batteries. As a result, they are often used in medical equipment and devices. These types of batteries may also be used in power tools, electric bikes and electrical hobby uses; it is even possible to use them to power laptops and electric powertrain cars.
There are also lithium-nickel-manganese-cobalt-oxide batteries, also known as lithium-manganese-cobalt-oxide batteries, or NMC. Lithium-nickel-manganese-cobalt-oxide batteries are made of several materials common in other lithium-ion batteries. Like other varieties of lithium-ion batteries, NMC batteries can have either a high specific energy or high specific power, and are most commonly used in power tools and in powertrains for vehicles.
Manganese uses: stainless steel
Generally manganese is added to stainless steel during melting to assist in deoxidation, and to prevent the formation of iron-sulfide inclusions, which can cause hot cracking problems.
Traditionally, stainless steel is made from chromium and nickel. The nickel is there to provide strength to the metal, which also contains about 1 percent manganese. However, there is a trend beginning to replace the nickel partly or completely with manganese, bumping the content up to as much as 16 percent and creating the so-called 200 Series. This replacement has been considered for years to help reduce the impact of nickel price fluctuations on the alloy surcharge, according to the European Stainless Steel Development Association.
Securities Disclosure: I, Kristen Moran, hold no direct investment interest in any company mentioned in this article.