The Role of Manganese Metal

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Manganese is a silver-gray metal, much like iron, but softer than iron. If small amounts of impurities—-carbon or silicon are contained in the manganese, it will become very hard, and brittle. The most important role of manganese alloys is to manufacture manganese steel.

If 2.5-3.5% manganese powder is added into the steel, the obtained low manganese is simply too brittle to withstand a strike, fragile like glass; however, it will turn into hard and resilient high manganese steel by adding more than 13% manganese. High manganese steel becomes very soft when heated to pale orange, very easy to do all kinds of manganese metal processing. Further, it will not be attracted by a magnet for it is non-magnetic. Now, manganese steel is largely used to produce steel mill, ball bearings, bulldozer and excavator buckets and other components often subject to wear, as well as tracks, bridges and so on. The roof of Shanghai Cultural Plaza auditorium is in an innovative grid structure which is welded with thousands of manganese steel tubes. There is not a single pillar in a 76m in vertical, horizontal 138m fan shaped hall. With manganese steel as the structural material, it is very strong, and the use of materials is less than other steel that the average manganese steel consumption is only 45kg/m2. Militarily, the high-manganese steel can be manufactured into helmets, tanks armor, armour-piercing warheads. Manganese steel refining is to mix 60~70% soft tin with iron ore together.

In addition, manganese is also important manganese alloy, containing 30% manganese, with good mechanical strength. Manganese-copper-nickel alloy (known as manganin), consisting of 84% steel, 12% manganese and 4% nickel, its resistance changes little with temperature, so it’s used to make sophisticated electrical equipment. The principal manganese compound is manganese dioxide, which largely exists in nature in the form of pyrolusite.

Pyrolusite was known back in prehistoric times. Manganese dioxide powder is black. The dry black powder in dry batteries is manganese dioxide. Manganese dioxide can catalyze the oxidation of oil, often added to the paint, in order to speed up the drying. In the manufacture of glass, manganese dioxide was often added to eliminate the green in glass to make it colorless and transparent. Another important compound of manganese is potassium permanganate (referred to as the “gray manganese oxide”). Potassium permanganate is purple needle-like crystal. Just a little potassium permanganate is sufficient to make a big bucket of water purple. It is a strong oxidizing agent, bactericidal. In China public places, a bucket of water violet disinfection is usually put next to a tea mug, known as “gray manganese water” which actually is the potassium permanganate solution, with a millesimal concentration, undrinkable as it is emetic, used as gastric lavage and emetic agent in medicine and an oxidizing agent in analytical chemistry which is as titrant for chemical analysis in the famous potassium permanganate titration. Potassium permanganate is often reduced into manganese dioxide. There is often some black scum in the bottom of “Manganese gray water” and that is manganese dioxide.

Besides, manganese carbonate is an important white pigment, while manganese sulfate is agriculturally utilized as seed germination agents or manganese fertilizer—-micronutrients fertilizer. In the body of animals and plants, the content of manganese is generally no more than a few hundred thousandths, while as much as five ten thousandths in red ants; even up to a few percent in some bacteria. Manganese in humans is four millionths, most located in heart, liver and kidney, mainly having an effect on the body’s growth, the formation of blood and endocrine function.

In nature, manganese is one of the widely distribution elements, accounting for three over ten thousand of the total number of atoms in the earth’s crust. The most important manganese mine is pyrolusite and psilomelane. Although the amount of manganese in seawater is little, but there is up to three thousandths of manganese in the depths of the ocean mud. Some people predict that people will start seabed mining in the near future!