Standard ferromanganese, also known as high-carbon ferromanganese, is one of the ferromanganese alloys directly smelted from manganese ore. The manganese content is between 74% and 82%, and the carbon content is between 7% and 7.5%. It is produced by a blast furnace or a submerged arc furnace. The alloy is smelted by the high manganese slag method or abandoned slag method. The high manganese slag is actually slag containing 30-42% Mn. Due to its high manganese value, the slag is recycled as a raw material for the production of manganese metal by the electrolytic process or for the production of silicomanganese alloys. Avoid adding lime to maintain high manganese levels. The practice of rejecting slag is to use slag containing 10-20% Mn. This level is too low to economically extract more manganese value. Lime is used to keep the manganese content of the slag low.
Silico-manganese is produced by the carbothermal reduction of manganese ore in a submerged arc furnace. It contains 65–68% Mn, 12.5–18.5% Si and 1.5–3% C. As with ferrochrome, high silicon content reduces the carbon content in manganese alloys. The smelting of silicon manganese requires a silicon source and a manganese source. In addition to manganese ore and flux, the charge also includes high manganese slag, siliceous manganese ore, or quartz. Due to the reduction of silica, the melting temperature is higher than that of standard ferromanganese alloys.
Ferromanganese–silicon is also known as low-carbon silicon manganese. It contains 63–66%Mn, 28–32%Si and less than 0.08%C. Its low carbon content is due to the high silicon content. High silicon is obtained by reducing quartz in the presence of silicomanganese. The alloy is primarily used as a master alloy for the production of low-carbon-grade ferromanganese alloys and is also used in stainless steel manufacturing processes.