Metallic silicon block is mainly used as an additive for non-ferrous alloys. It is a non-metallic element, gray and metallic in color, hard and brittle. The silicon content accounts for about 26% of the shell mass; the relative atomic mass is 28.8. The density is 2.33g/cm3. The melting point is 1410°C, the boiling point is 2355°C, and the resistivity is 2140Ω·m.
According to the content of iron, aluminum and calcium in the metal silicon block, the metal silicon block can be divided into different brands such as 553, 441, 411, 421, 3303, 3305, 2202, 2502, 1501, 1101 and so on.
Industrially, silicon blocks are usually produced by reducing silica with carbon in an electric furnace. Chemical reaction equation: SiO22C→Si2CO The purity of silicon obtained in this way is 97~98%, which is called metallic silicon. After another recasting, the impurities are removed with acid to obtain metallic silicon with a purity of 99.7 to 99.8%. The main component of silicon block is silicon, so it has similar properties to silicon. There are two allotropes, amorphous and shaped. Amorphous is a gray-black powder, which is actually a kind of microcrystalline.
Silicon block is industrially purified elemental silicon and is mainly used for the production of organic silicon, the preparation of high-purity semiconductor materials and the preparation of special-purpose alloys. Mainly used as antioxidant in refractory industry. The main industrial applications of metallic silicon are as follows:
(1) Production of silicone rubber, silicone resin, silicone oil and other silicones
It has good elasticity and high temperature resistance and is used in the manufacture of medical supplies, high temperature resistant gaskets, etc. Silicone resin is used to produce insulating paint, high temperature resistant coatings, etc. Silicone oil is an oily substance whose viscosity is less affected by temperature. It is used to produce lubricants, polishes, fluid springs, dielectric fluids, etc. It can also be processed into colorless and transparent liquids and sprayed on buildings as waterproofing agents. Object surface.
(2) Manufacturing high-purity semiconductors from silicon blocks
Nearly all modern large-scale integrated circuits are made of high-purity metallic silicon, and high-purity silicon blocks are also the main raw material for the production of optical fibers. It can be said that it has become a basic pillar industry in the information age.
(3)Alloy preparation
Silicon block aluminum alloy is an alloy containing a large amount of silicon. Silicon-aluminum alloy is a strong composite deoxidizer. It can replace pure aluminum in the steelmaking process, improve the utilization rate of deoxidizer, purify molten steel, and improve the quality of molten steel. The alloy has low density, small thermal expansion coefficient, good casting performance and wear resistance. The alloy castings cast with it have high impact resistance and good high-pressure density, which can greatly extend the service life. Commonly used in manufacturing aerospace vehicles and the automotive industry.
Chemical silicon production is carried out continuously. The conditions inside the furnace are not permanent either. Chemical silicon production is a process in which electrical energy is converted into thermal energy in an electric furnace, and then the thermal energy is used to directly heat materials to produce chemical reactions. Therefore, the electrical characteristics in the furnace are very important. Melting implements closed arc operation to maintain high temperature of the furnace, improve thermal efficiency, and improve electric furnace utilization.
