Ferrosilicon is an alloy of iron and silicon. Ferrosilicon is an iron silicon alloy made from coke, steel chips and quartz (or silica) by electric furnace smelting. Because silicon and oxygen are easy to synthesize silica, ferrosilicon is often used as deoxidizer in steelmaking. At the same time, due to the large amount of heat released during the formation of SiO2, it is also beneficial to improve the temperature of molten steel while deoxidizing. At the same time, ferrosilicon can also be used as an alloying element additive, which is widely used in low-alloy structural steel, spring steel, bearing steel, heat-resistant steel and electrical silicon steel. Ferrosilicon is commonly used as a reducing agent in ferroalloy production and chemical industry.
(1) It is used as deoxidizer and alloying agent in steelmaking industry. In order to obtain steel with qualified chemical composition and ensure the quality of steel, deoxidation must be carried out in the final stage of steelmaking. The chemical affinity between silicon and oxygen is great. Therefore, ferrosilicon is a strong deoxidizer for steelmaking, which is used for precipitation and diffusion deoxidation. Adding a certain amount of silicon to the steel can significantly improve the strength, hardness and elasticity of the steel. Therefore, ferrosilicon is also used as alloying agent when smelting structural steel (containing silicon 0.40-1.75%), tool steel (containing SiO. 30-1.8%), spring steel (containing SiO. 40-2.8%) and silicon steel for transformer (containing silicon 2.81-4.8%).
(2) It is used as inoculant and spheroidizing agent in cast iron industry. Cast iron is an important metal material in modern industry. It is cheaper than steel, easy to melt and smelt, and has excellent casting performance and much better seismic capacity than steel. In particular, the mechanical properties of nodular cast iron are equal to or close to those of steel. Adding a certain amount of ferrosilicon to cast iron can prevent the formation of carbide in iron and promote the precipitation and spheroidization of graphite. Therefore, ferrosilicon is an important inoculant (to help precipitate graphite) and spheroidizing agent in the production of nodular cast iron.
(3) Used as reducing agent in ferroalloy production. Not only the chemical affinity between silicon and oxygen is great, but also the carbon content of high silicon ferrosilicon is very low. Therefore, high silicon ferrosilicon (or siliceous alloy) is a common reducing agent in the production of low-carbon ferroalloy in ferroalloy industry.
(4) 75# ferrosilicon is often used in the high-temperature smelting of metal magnesium in the process of magnesium smelting by Pijiang method The replacement of magnesium in MgO will consume about 1.2 tons of ferrosilicon for each ton of metal magnesium, which plays a great role in the production of metal magnesium.
(5) For other purposes. Ground or atomized ferrosilicon powder can be used as suspended phase in beneficiation industry. It can be used as the coating of electrode in electrode manufacturing industry. High silicon ferrosilicon can be used to manufacture silicone and other products in the chemical industry.
Among these uses, steelmaking industry, foundry industry and ferroalloy industry are the largest users of ferrosilicon. They consume more than 90% of ferrosilicon. Among various brands of ferrosilicon, 75% ferrosilicon is the most widely used at present. In the steelmaking industry, about 3-5kg75% ferrosilicon is consumed for every 1t of steel produced.
