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.

Silicomanganese (SiMn), a ferroalloy with high contents of manganese and silicon, is made by heating a mixture of the oxides manganese oxide (MnO2), silicon dioxide (SiO2), and iron oxide (Fe2O3), with carbon in a furnace. They undergo a thermal decomposition reaction. It is used as a deoxidizer and an alloying element in steel.