There are two types of reduction smelting of ferromanganese: flux method (also called low manganese slag method) and fluxless method (high manganese slag method). The principle of flux method is the same as that of blast furnace smelting, except that the coke used for heating is replaced by electric energy. By adding lime to form a high basicity slag (CaO/SiO2 is 1.3 ~ 1.6) to reduce the loss of manganese.
In the flux-free smelting process, lime is not added, and low-iron low-phosphorus manganese-rich slag with low alkalinity (CaO/SiO2 less than 1.0) and high manganese content is formed. This method has a small amount of slag, which can reduce power consumption, and can reduce the evaporation loss of manganese due to the lower slag temperature. At the same time, the by-product manganese-rich slag (containing 25-40% of manganese) can be used as a raw material for smelting manganese-silicon alloys, achieving a higher Comprehensive recovery rate of manganese (over 90%).
