Ferrosilicon is a common additive in steel smelting process.It has a good deoxidizing effect in steel smelting process.This is because ferrosilicon reacts with the oxygen in liquid steel to form silica,which floats on the surface of liquid steel,thus achieving good deoxidizing effect.The choice of ferrosilicon raw materials also has a great impact on the quality of ferrosilicon.In order to deepen our understanding,we follow ferrosilicon manufacturers to see how to choose ferrosilicon raw materials.Ferrosilicon is mainly used as deoxidizer and alloy for steelmaking.Phosphorus(P)and sulfur(S)are impurities which have great influence on the quality of steel.Therefore,the phosphorus and sulfur content is very low.Phosphorus exists in silica as phosphorus pentoxide(P2O5),and most of phosphorus pentoxide is reduced into ferrosilicon by carbon during smelting.Therefore,phosphorus pentoxide in silica is required to be no more than 0.02%.Sulfur content in silica,due to the smelting process of sulfur(S)and silicon(Si)formed silicon sulfide,such as SiS,SiS2 and other compounds,these compounds at high temperature volatile away,so silica sulfur content is not required.The content of calcium oxide(CaO)and magnesium oxide(MgO)in silica is relatively high,which will increase the amount of slag and erode the iron mouth during smelting.Therefore,the total content of calcium oxide and magnesium oxide in silica is required to be less than 1%.