Ferromanganese, a ferroalloy with high content of manganese, is made by heating a mixture of the oxides MnO2 and Fe2O3, with carbon in a furnace. They undergo a thermal decomposition reaction. It is used as a deoxidizer for steel. A North American standard specification is ASTM A99. The ten grades covered under this specification includes;
Standard ferromanganese
Medium-carbon ferromanganese
Low-carbon ferromanganese
A similar material is a pig iron with high content of manganese, is called spiegeleisen.
