Production Of Ferrosilicon

In the production of ferrosilicon, the main equipment used is submerged arc reduction furnace, the main raw materials are coke, steel chips, quartz (or silica). The silicon content of ferrosilicon is controlled by the addition of iron raw materials. In addition to the selection of pure silica and reducing agent, the production of high purity ferrosilicon should be refined outside the furnace to reduce the impurities such as aluminum, calcium and carbon in the alloy. Ferrosilicon with Si≤ 65% can be smelted by closed electric furnace, and ferrosilicon with Si≥ 70% can be smelted by open electric furnace or semi-closed electric furnace.

Electrical steel requires high purity ferrosilicon, and some elements such as Ti and Mn need to be pure raw materials to meet the requirements. The Al, Ca and c in ferrosilicon are solved by off-furnace refining. There are three kinds of refining methods for ferrosilicon outside furnace: slag refining, oxygen refining and chlorine evaporation. Among them, slag refining method is to melt fossil quartz, limestone and dolomite in an electric furnace to get synthetic slag, will be out of the oven and slag in the ladle mixed, through a package of furnace repeatedly dumped several times, can get Al< 0.01% ferrosilicon. Refining 1t of ferrosilicon consumes 2000 ~ 2500kWh of electric energy. Synthetic slag containing 45% ~ 55% SiO2, 25% ~ 30% CaO, 10% ~ 13% CaF2 and 8% ~ 10% FeO is used, and the dosage is 13% ~ 17% of the weight of ferrosilicon.