Manganese, manganese ore, ferromanganese and manganese dioxide:

Manganese, manganese ore, ferromanganese and manganese dioxide:

Manganese (Mn) is a hard, silvery white metal with a melting point of 1,244° C. Ordinarily too brittle to be of structural value itself, it is an essential agent in steelmaking. It has a properties to remove impurities such as sulfur and oxygen and adds important physical properties to steel.

The most important manganese ores are the oxides pyrolusite, romanechite, manganite, and hausmannite and the carbonate ore rhodochrosite. Rhodonite and braunite, both silicate ores, are frequently found with the oxides. Only ores containing greater than 35 percent manganese are considered commercially exploitable.

Some manganese ores are upgraded by washing, jigging and undersized ores can be agglomerated by sintering.

Manganese is used principally in the form of alloys with iron. The most important of these alloys, which are used in steelmaking, are ferromanganese. Ferromanganese, an alloy of iron and manganese, used in the production of steel. This is a product of the blast furnace, obtained by treating pyrolusite (manganese ore) in a blast furnace with iron ore and carbon. It is containing, besides iron, 74 to 82% of manganese and some silicon, phosphorus, sulfur and carbon. It is used as a deoxidizer and for the introduction of manganese into steel.

It is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon in a furnace. They undergo thermal decomposition reaction. Standard ferromanganese specifications given below:

Mn - 74.0-82.0%

C - 7.5% max.

Si - 1.2% max.

P - 0.35% max.

S - 0.05% max.

In cast iron, manganese is used mainly to counteract the bad effects of sulfur. In steel, manganese acts as a deoxidizer and combines with sulfur, thereby improving the hot-working properties of the steel. Also improves the strength, toughness of steel.

Other use of manganese ore is in batteries as manganese dioxide. Manganese dioxide (MnO2) is blackish or brown solid in color, occurs naturally as the mineral pyrolusite, which is the main ore of manganese. The principal use for MnO2 is for dry-cell batteries, such as the alkaline battery and the zinc-carbon battery.