The chemical affinity between silicon and oxygen is very high, so ferrosilicon is used as a deoxidizer (precipitation deoxidation and diffusion deoxidation) in the steelmaking industry. Except for boiled steel and semi-killed steel, the silicon content in steel should not be less than 0.10%. Silicon does not form carbides in steel, but exists in solid solution in ferrite and austenite. Silicon has a strong effect on improving the strength of the solid solution in steel and the cold working deformation hardening rate, but reduces the toughness and plasticity of the steel; it has a moderate effect on the hardenability of the steel, but it can improve the tempering stability and oxidation resistance of the steel, so silicon Iron is used as an alloying agent in the steelmaking industry. Silicon also has the characteristics of large specific resistance, poor thermal conductivity and strong magnetic conductivity. Steel contains a certain amount of silicon, which can improve the magnetic permeability of steel, reduce hysteresis loss, and reduce eddy current loss. Electrical steel contains 2% to 3% Si, but requires low titanium and boron content. Adding silicon to cast iron can prevent the formation of carbides and promote the precipitation and spheroidization of graphite. Silicon-magnesia iron is a commonly used spheroidizing agent. Ferrosilicon containing barium, zirconium, strontium, bismuth, manganese, rare earths, etc. is used as an inoculant in cast iron production. High-silicon ferrosilicon is a reducing agent used in the ferroalloy industry to produce low-carbon ferroalloys. Ferrosilicon powder containing about 15% silicon (particle size <0.2mm) is used as a weighting agent in heavy media mineral processing.
The ferrosilicon production equipment is a submerged arc reduction electric furnace. The silicon content of ferrosilicon is controlled by the dosage of iron raw materials. In addition to using pure silica and reducing agents to produce high-purity ferrosilicon, refining outside the furnace is also required to reduce impurities such as aluminum, calcium, and carbon in the alloy. The ferrosilicon production process flow is shown in Figure 4. Ferrosilicon containing Si ≤ 65% can be smelted in a closed electric furnace. Ferrosilicon with Si ≥ 70% is smelted in an open electric furnace or a semi-closed electric furnace.
Post time: Apr-17-2024
