Ferrosilicon is an iron alloy made of iron and silicon. Ferrosilicon is an iron silicon alloy made of coke, steel chip, quartz (or silica) as raw materials by electric furnace smelting. Because silicon and oxygen are easy to combine into silicon dioxide, so ferrosilicon is often used in steelmaking as a deoxidizer, and because of the generation of SiO2 release a lot of heat, in the deoxygenation at the same time, to improve the temperature of molten steel is also beneficial. At the same time, ferrosilicon can also be used as an alloying element additive, 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.
Silicon (Taiwan, Hong Kong called silicon) is a chemical element, its chemical symbol is Si, the old silicon. Atomic number 14, relative atomic mass 28.09, there are two kinds of amorphous and crystalline allomorphs, allomorphs have amorphous silicon and crystalline silicon. A metalloid element belonging to group IVA on the periodic table.
Crystalline silicon is steel gray, amorphous silicon is black, density 2.4g/cm3, melting point 1420℃, boiling point 2355℃, crystalline silicon belongs to atomic crystal, hard and shiny, semiconductor properties. The chemical properties of silicon are more active, can be combined with oxygen and other elements at high temperature, insoluble in water, nitric acid and hydrochloric acid, soluble in hydrofluoric acid and alkali, used to make alloys such as ferrosilicon, silicon steel, etc., single crystal silicon is an important semiconductor material, used in the manufacture of high-power transistors, rectifiers, solar cells, etc. Silicon is widely distributed in nature, containing about 27.6% in the earth's crust, mainly in the form of silica and silicate. Crystalline silicon is dark blue, very brittle, and is a typical semiconductor. The chemical properties are very stable. At room temperature, it is difficult to react with other substances except hydrogen fluoride.
Uses of silicon:
High purity monocrystalline silicon is an important semiconductor material. P-type silicon semiconductor is formed by adding trace of group IIIA element into single crystal silicon. By mixing in small amounts of Group VA elements, N-type and P-type semiconductors are combined to make solar cells that convert radiant energy into electricity. It is a promising material for developing energy sources.
(2) cermet, an important material for space navigation. The ceramic and metal mixed sintering, made of cermet composite material, it is high temperature resistant, rich toughness, can be cut, both inherited the respective advantages of metal and ceramic, and make up for the congenital defects of both. The first space shuttle, the Columbia, was able to withstand the heat of friction as it sped through a dense atmosphere thanks to its shell of 31,000 silicon tiles.
Optical fiber communication, the latest means of modern communication. Using pure silica to pull out high transparency glass fiber, laser in the glass fiber path, countless times of total reflection forward transmission, instead of heavy cable. Fiber optic communication capacity is high, a hair so fine glass fiber, can simultaneously transmit 256 telephone, it is not subject to electrical, magnetic interference, not afraid of eavesdropping, with a high degree of confidentiality. Optical fiber communication will revolutionize human life in the 21st century.
④ excellent performance of silicon organic compounds. For example, silicone plastic is an excellent waterproof coating material. Spraying silicone on the walls of the underground railway can solve the problem of water seeping once and for all. On the appearance of ancient cultural relics and sculptures, a thin layer of silicone plastic can prevent the growth of moss and resist wind and rain and weathering. The Monument to the People's Heroes in Tian 'anmen Square is made of silicone plastic, so it is always white and fresh.
In addition, in steelmaking industry, ferrosilicon powder is often used as ingot cap heating agent to improve the quality and recovery rate of steel ingot because it can release a lot of heat at high temperature.
(2) Used as inoculant and spheroidizing agent in the 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 earthquake resistance than steel. Especially ductile iron, its mechanical properties reach or close to the mechanical properties of steel. Adding a certain amount of ferrosilicon in 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 ductile iron.
(3) Used as reducing agent in ferroalloy production. Not only the chemical affinity between silicon and oxygen is very large, but also the carbon content of high silicon ferrosilicon is very low. Therefore, high silicon ferrosilicon (or silicon alloy) is a kind of reducing agent commonly used in the production of low carbon ferroalloys in the ferroalloy industry.
(4)75# ferrosilicon is often used in the high temperature smelting process of magnesium metal in the PI Jiang method, and the magnesium in CaO.MgO is replaced. Every ton of magnesium metal is consumed about 1.2 tons of ferrosilicon, which plays a great role in the production of magnesium metal.
(5) Other uses. The fine or atomized ferrosilicon powder can be used as suspension phase in the mineral processing industry. It can be used as coating of electrode in welding rod manufacturing. High silicon ferrosilicon is used in the chemical industry to make products such as silicone.
Among these uses, the steelmaking industry, the casting industry, and the ferroalloy industry are the largest users of ferrosilicon. Together, they consume about 90% or more of the ferrosilicon. In a variety of different grades of ferrosilicon, the most widely used is 75% ferrosilicon. In the steelmaking industry, about 3-5kg75% ferrosilicon is consumed per 1t of steel produced.
Ferrosilicon is an essential deoxidizer in steelmaking industry. In torch steel, ferrosilicon is used for precipitation deoxygenation and diffusion deoxygenation. Brick iron is also used as an alloying agent in steelmaking. Adding a certain amount of silicon to the steel can significantly improve the strength, hardness and elasticity of the steel, improve the magnetic permeability of the steel, and reduce the hysteresis loss of the transformer steel. The silicon in general steel is 0.15%-0.35%, the silicon in structural steel is 0.40%-1.75%, the silicon in tool steel is 0.30%-1.80%, the silicon in spring steel is 0.40%-2.80%, the silicon in stainless acid-resistant steel is 3.40%-4.00%, and the silicon in heat-resistant steel is 1.00%-3.00%. Silicon steel contains 2% ~ 3% or more silicon.
High silicon ferrosilicon or silicic alloys are used in the ferroalloy industry as reducing agents for the production of low carbon ferroalloys. The addition of ferrosilicon to cast iron can be used as the inoculating agent of ductile iron, and can prevent the formation of carbide, promote the precipitation and spheroidization of graphite, and improve the performance of cast iron.
