Metal silicon, also known as crystalline silicon or industrial silicon, is mainly used as an additive to non-ferrous based alloys. Silicon is a non-metallic element that is gray, metallic, hard and brittle. The content of silicon is about 26% of the mass of the earth's crust; the relative atomic mass is 28.8, the density is 2.33 g/cm3, the melting point is 1410 ° C, the boiling point is 2355 ° C, and the electrical resistivity is 2140 Ω·m.
Additional products of metal silicon include silicon micropowder, side skin silicon, black skin silicon, metal silicon slag, and the like. Among them, silicon micropowder, also known as silicon powder, micro silicon powder or silica fume, is widely used in refractory materials and concrete industries.


Industrially, metal silicon is usually produced by reducing silica from carbon in an electric furnace. Chemical reaction equation: SiO2 + 2C → Si + 2CO The purity of the silicon obtained is 97~98%, called metal silicon. Further, it is melted, recrystallized, and the impurities are removed with an acid to obtain metal silicon having a purity of 99.7 to 99.8%. The metal silicon component is mainly silicon and thus has similar properties to silicon. Silicon has two allotropes of amorphous silicon and crystalline silicon. Amorphous silicon is a gray-black powder and is actually a microcrystal. Crystalline silicon has the crystal structure and semiconducting properties of diamond, melting point 1410 ° C, boiling point 2355 ° C, Mohs hardness 7, brittleness. Amorphous silicon is chemically active and can burn intensely in oxygen. It reacts with non-metals such as halogen, nitrogen and carbon at high temperatures, and also reacts with metals such as magnesium, calcium and iron to form silicides. Amorphous silicon is hardly soluble in all inorganic and organic acids including hydrofluoric acid, but is soluble in a mixed acid of nitric acid and hydrofluoric acid. The concentrated sodium hydroxide solution dissolves amorphous silicon and releases hydrogen. Crystalline silicon is relatively inactive, does not combine with oxygen even at high temperatures, it is not soluble in any inorganic acid and organic acid, but is soluble in mixed acid of nitric acid and hydrofluoric acid and concentrated sodium hydroxide solution.




Metallic silicon is an industrially purified elemental silicon that is mainly used in the production of silicones, the preparation of high-purity semiconductor materials, and the preparation of alloys for special applications. In the refractory industry, it is mainly used as an antioxidant. The main applications of metal silicon in the industry are as follows:




(1) Production of silicone rubber, silicone resin, silicone oil and other silicones


Silicone rubber has good elasticity and high temperature resistance, and is used for making medical supplies and high temperature resistant gaskets.


Silicone resin is used to produce insulating varnish, high temperature coating, etc.


Silicone oil is an oil whose viscosity is little affected by temperature. It is used to produce advanced lubricants, polishes, fluid springs, dielectric liquids, etc. It can also be processed into a colorless and transparent liquid, which is sprayed as a high-grade waterproofing agent. On the surface of the building.


(2) Manufacturing high-purity semiconductors


Modern large-scale integrated circuits are almost all made of high-purity metal silicon, and high-purity metal silicon is also the main raw material for producing optical fibers. It can be said that metal silicon has become the basic pillar industry in the information age.


(3) Formulating alloy


Silicon-aluminum alloy is the largest amount of silicon alloy. Silicon-aluminum alloy is a strong composite deoxidizer. It can improve the utilization rate of deoxidizer in the process of steel making, and can purify molten steel and improve the quality of steel. Small, low coefficient of thermal expansion, good casting performance and anti-wear performance. The alloy castings cast with it have high impact resistance and good high-pressure compactness, which can greatly improve the service life. It is commonly used to produce spacecraft and auto parts. .


Silicon-copper alloy has good welding performance, and is not easy to generate sparks when subjected to impact. It has an explosion-proof function and can be used for making storage tanks.


The addition of silicon to the steel to form a silicon steel sheet can greatly improve the magnetic permeability of the steel and reduce the hysteresis and eddy current losses. It can be used to manufacture the core of the transformer and the motor to improve the performance of the transformer and the motor.


The main producing areas of metal silicon: Yunnan, Sichuan, Guizhou, Guangxi in the southwest, Hunan and Hubei in Central China, Fujian in the east, and Heihe, Linjiang and Jilin and Liaoning in Heilongjiang, and Inner Mongolia.