Silicon manganese alloy is mainly used as the intermediate of deoxidizer and alloying agent in steel production, and is also the main raw material for medium and low carbon ferromanganese production. Silicon manganese alloy is an alloy composed of manganese, silicon, iron and a small amount of carbon and other elements. It is a kind of iron alloy with wide use and large output. Its consumption takes the second place in ferroalloy products of electric furnace. Silicon and manganese in silicon manganese alloy have strong affinity with oxygen. When silicon manganese alloy is used in steelmaking, the deoxidized products MnSiO3 and MnSiO4 are melted at 1270 ℃ and 1327 ℃ respectively, which have the advantages of low melting point, large particles, easy floating and good deoxidization effect. Under the same conditions, if manganese or silicon is used for deoxidation alone, the burning loss rate is 46% and 37% respectively, while if silicon manganese alloy is used for deoxidation, the burning loss rate of both is 29%. Therefore, it has been widely used in steelmaking. Its output growth rate is higher than the average growth rate of ferroalloy, and it has become an indispensable composite deoxidizer and alloy additive in the steel industry.
Silicon manganese alloy with carbon content below 1.9% is also used to produce medium and low carbon ferromanganese and semi products of silicothermic manganese metal. In ferroalloy production enterprises, the silicon manganese alloy used for steelmaking is usually called commercial silicon manganese alloy, the silicon manganese alloy used for smelting low-carbon iron is called self use silicon manganese alloy, and the silicon manganese alloy used for smelting metal is called high silicon silicon manganese alloy.
Manganese can be combined with silicon to synthesize silicides MnSiO3, MnSiO and MnSiO3. It can be seen from the silicon manganese state diagram that the * * * stable silicide is MnSi. As the negative value of free energy of manganese silicide production is far greater than the negative value of free energy of manganese carbide production, the higher the silicon content in silicon manganese alloy, the lower the carbon content.