Manganese: An Unsung Hero

July 28, 2009

In the latest installment in our series on minor metals, Hard Assets Investor digs into this critical steelmaking ingredient.
  • Manganese in steel production
  • Who are the major players?
  • How can you invest?

 

It's the world's fourth-most consumed metal by weight, and the twelfth-most abundant in the Earth's crust. All steels contain it. And the U.S. is 100% reliant on imports of it.

But who has ever heard of manganese?f

 

What Is Manganese?

Manganese is a brittle, hard gray-white metal that looks much like iron, and is present in practically everything made of steel. It's also used in a slew of other applications, including dry cell batteries (about 20 billion per year), aluminum cans (about 100 billion per year), electronic circuits as well as fungicides and pesticides. And although manganese may be fatal to bugs and fungus, it's vital to our good health as humans: The recommended daily intake of manganese is 2-5 mg per day.

Manganese has been in use since the Stone Age, when it was used as a pigment in cave paintings. But it was not until 1771 that it was recognized as an element by Swedish chemist Carl Wilhelm Scheele, the same scientist who first identified molybdenum. (See Molybdenum: Mighty Tough.)

By the middle of the nineteenth century, major advances in the use of manganese had occurred. In 1856, Robert Mushet patented its use in ridding steel of excess sulfur and oxygen. Then, in 1866, Sir William Siemens obtained a patent to use ferromanganese to control the levels of sulfur and phosphorus in steel. That same year, French electrical engineer Georges Leclanché patented his dry cell battery - now known as Leclanché cells - which used manganese dioxide as a depolarizer.

 

Uses Of Manganese

Metallurgical

Both historically and currently, the greatest use of manganese - about 90% - is for production of steel and cast iron, for which no suitable substitute for the metal has yet been found. (The remaining 10% is used in making batteries, chemicals and aluminum cans.)

According to the International Manganese Institute (IMnI), of the manganese used in steelmaking, 70% is used as an alloying element, while the remaining 30% is employed for "its properties as a sulphide former and deoxidant."

Although detailed and up-to-date figures are available neither for worldwide manganese consumption by end use nor world steel market consumption, 2006 USGS figures for the U.S. probably remain indicative as to the breadth and depth of its use.

 

 

Notes:    Based on an estimated apparent consumption of 1.05 million tonnes contained manganese

              * Assumed to have been consumed in the manufacture of steel mill products

              Includes steel for converting and processing nonclassified shipments and some steel shipped by steel service centers and   distributors

              Includes forgings not elsewhere classified, industrial fasteners and ordnance and other military products

 

Source: USGS

 

Across all grades, estimates for the average manganese content of steel range from some 0.7% (USGS), to "...around 10kg Mn alloys per mt of steel produced" (IMnI's figure for 2008). In general, however, developing economies use more manganese in their steel than developed ones.

The manganese content of the major different types of steel are:

Alloy Steels: 0.05-2.1% (full alloy steels, high-strength low-alloy steels (HSLA) and tool steels - other than carbon and stainless steel)

Carbon Steels: 0.05-1.65%

Hadfield Steels: 10-14%

Stainless Steels: 0-19%

In steelmaking, manganese is usually added in the form of a ferroalloy. This includes three grades of ferromanganese (FeMn) - one standard (high-carbon - HC) grade containing 65-79% Mn and 7% carbon, and two refined grades with medium-carbon (MC) and low-carbon (LC) - and silicomanganese (SiMn), which contains 60-77% Mn and around 2% carbon. Cost, the type of steel being made and the process being used usually determine which ferroalloy is used.

The U.S. military is a particularly notable consumer of manganese: In its weapons systems and munitions, the Department of Defense uses approximately 25,041.8 short tons of manganese ore chemical/metal grade, 7,897.0 short tons of ferro-manganese (either carbon or silicon) and 1,368.8 short tons of electrolytic manganese metal (EMM) each year.

In addition to its use as an alloy in steel and cast iron, manganese is also employed as an alloy (in very much lesser amounts) with aluminum, copper, nickel, titanium and zinc. It's also used in miniscule amounts for electronic applications, with, amongst other metals, bismuth, gold and silver.

 

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