Silicon-manganese alloys with a carbon content of less than 1.9% are also semi-finished products used for the production of medium and low carbon ferromanganese and electro-silicothermal metal manganese. In ferroalloy production enterprises, the silicon-manganese alloy used in steelmaking is usually called commercial silicon-manganese alloy, the silicon-manganese alloy used in smelting low carbon iron is called self-use silicon-manganese alloy, and the silicon-manganese alloy used in metal smelting is called high silicon alloy. Silicon manganese alloy. Manganese can be combined with silicon to form silicides MnSiO3, MnSiO and MnSiO3. It can be seen from the silicon manganese state diagram that the most stable silicide is MnSi. Due to the negative value of the free energy of manganese silicide generation, it is far greater than the negative value of the free energy of manganese carbide production. The higher the silicon content in the silicon-manganese alloy, the lower the carbon content.
Under the same conditions, using manganese or silicon alone for deoxidation, the burning loss rate is 46% and 37%, respectively, while with silicon-manganese alloy deoxidation, the burning loss rate of the two is 29%. Therefore, it has been widely used in steelmaking, and its output growth rate is higher than the average growth rate of ferroalloys, and it has become an indispensable composite deoxidizer and alloy additive in the iron and steel industry.
The raw materials for the production of manganese-silicon alloys are manganese ore, manganese-rich slag, silica, coke, dolomite (or limestone), and fluorite. One manganese ore or a mixture of several manganese ores (including manganese-rich slag) can be used to produce manganese-silicon alloys. Since manganese-silicon alloy requires lower iron and phosphorus content than high-carbon ferromanganese, manganese ore for smelting manganese-silicon alloy is required to have higher manganese-iron ratio and manganese-phosphorus ratio. The higher the manganese content of the manganese ore used, the better the indicators.