Silicon manganese alloy is an alloy composed of manganese, silicon, iron, a small amount of carbon, and other elements. It is a widely used and high-yield iron alloy. Silicon manganese alloy is a commonly used composite deoxidizer in steelmaking, as well as a reducing agent for low-carbon manganese iron and electric silicon thermal production of metallic manganese in production. Silicon manganese alloys can be smelted continuously in large, medium, and small submerged arc furnaces.

    The consumption of silicon manganese alloy ranks second among electric furnace ferroalloy products. The silicon and manganese in silicon manganese alloys have a strong affinity for oxygen. When using silicon manganese alloys in steelmaking, the deoxidation products MnSiO3 and MnSiO4 produced melt at 1270 ℃ and 1327 ℃, respectively. They have the advantages of low melting point, large particles, easy floating, and good deoxidation effect. Under the same conditions, using manganese or silicon for deoxidation alone resulted in burn loss rates of 46% and 37%, respectively, while using silicon manganese alloy for deoxidation resulted in a burn loss rate of 29% for both. Therefore, it has been widely used in steelmaking, with a production growth rate higher than the average growth rate of ferroalloys, becoming an indispensable composite deoxidizer and alloy additive in the steel industry. Silicon manganese alloys with carbon content below 1.9% are still used as semi-finished products for the production of medium to low carbon ferromanganese and electric silicon thermal manganese metal. In ferroalloy production enterprises, the silicon manganese alloy used for steelmaking is usually referred to as commercial silicon manganese alloy, the silicon manganese alloy used for smelting low-carbon iron is referred to as self use silicon manganese alloy, and the silicon manganese alloy used for smelting metals is referred to as high silicon silicon manganese alloy. Manganese can react with silicon to form silicides MnSiO3, MnSiO, and MnSiO3. From the silicon manganese state diagram, it can be seen that the stable silicide is MnSi. Due to the negative value of the free energy for the formation of silicides in manganese, it is much greater than the negative value of the free energy for the production of carbides in manganese. In silicon manganese alloys, the higher the silicon content, the lower the carbon content.

    Silicon manganese alloys are produced by simultaneously reducing manganese oxide and silicon dioxide in manganese ore (including manganese rich slag) and silica using charcoal in a mineral thermal furnace. The indicators of normal furnace conditions in the production of silicon manganese alloy are stable working current, able to operate at full load, balanced and deep electrode insertion, uniform electrode consumption speed, normal lowering, with a lowering length of about 200mm per hour, easy opening and blocking of furnace holes, smooth iron and slag tapping, high temperature, good slag iron fluidity, and easy separation. The alloy composition is stable, with m (CaO+MgO)/m (SiO2) in the slag ranging from 0.7 to 0.8 and MnO below 10%. The normal composition of furnace gas is O2 less than 2% and H2 less than 8%. There is a slight negative pressure (-49Pa) inside the furnace, and the temperature inside the furnace is below 600 ℃.