Metallic silicon, also known as crystalline silicon or industrial silicon, its main purpose is as a non-ferrous alloy additives. Metal silicon is made of quartz and coke in the electric furnace smelting into the product, the main component of silicon content of about 98% (in recent years, containing 99.99% of Si is also included in the metal silicon), the remaining impurities for the iron, aluminum , Calcium and so on.
The nature of silicon
Silicon is one of the semi-metals, formerly known as "silicon". The melting point of 1420 ℃, the density of 2.34 grams per cubic centimeter. Hard and brittle. At room temperature insoluble in acid, soluble in alkali. The nature of metallic silicon and germanium, lead, tin similar to the semiconductor properties. Silicon in the crust is extremely rich in resources, second only to oxygen, accounting for more than a quarter of the total crust, in the form of silica or silicate. The purest silicon mineral is quartz or silica. Silicon has two kinds of allotropes: one for the dark brown amorphous powder, the nature of lively, can burn in the air; the other for the stability of the crystal (crystalline silicon). General silica and quartz for glass and other building materials, high quality quartz for the production of alloys, metals and single crystals
The use of silicon
Silicon for a large number of smelting into ferrosilicon alloy for the steel industry alloy elements, in a variety of metal smelting as a reducing agent. Silicon or aluminum alloy in the good components, the vast majority of cast aluminum alloy contains silicon. Silicon is the electronics industry, ultra-pure silicon raw materials, ultra-pure semiconductor monocrystalline silicon electronic devices with small size, light weight, good reliability and long life and other advantages. High-power transistors, rectifiers and solar cells made of silicon single crystals doped with specific trace impurities are better than those made with germanium monocrystals. Amorphous silicon solar cell research progress quickly, the conversion rate of more than 8%. Silicon molybdenum rod electric components up to the maximum temperature of 1700 ℃, with resistance is not easy to aging and good oxidation resistance. Silicon production of trichlorosilane, can be prepared hundreds of silicone lubricants and waterproof compounds. In addition, silicon carbide can be used as abrasive, high purity silica made of quartz tube is high purity metal smelting and lighting important material. The paper of the eighties - silicon people called silicon "eighties paper". This is because the paper can only record information, and silicon can not only record information, but also the processing of information processing to obtain new information. 1945 made the world's first electronic computer, equipped with 18,000 tubes, 70,000 resistors, 10,000 capacitors, the whole machine weight 30 tons, covering 170 square meters, equivalent to 10 house size. Today's electronic computers, due to advances in technology and material improvements, can accommodate tens of thousands of transistors on a nail-sized silicon, and have a range of functions such as input, output, operation, storage and control information. Microporous silicon calcium insulation material microporous silicon calcium insulation material is an excellent insulation material. It has the characteristics of small heat capacity, high mechanical strength, low thermal conductivity, no burning, non-toxic and tasteless, cutting and convenient transportation. It can be widely used in various thermal equipment and pipelines such as metallurgy, electric power, chemical industry and ship. The test, energy efficiency is better than asbestos, cement, vermiculite and cement perlite and other insulation materials. Special silicon calcium material can be used as a catalyst carrier, in the oil refining, automobile exhaust purification and other widely used.
Ultra-pure silicon (no more than a few atoms per atom of atoms) is the most important semiconductor materials, widely used in computers, microwave communications, optical fiber communications, solar power and so on. Semiconductor silicon material developed rapidly, the annual amount of monocrystalline silicon more than 2,500 tons, silicon consumption of 2.5 billion square inches. China's silicon material research and production has also been great development, the diameter of 3 inches below the single crystal has reached the international level, and the establishment of cutting, grinding, throwing process and equipment, but the overall level and the international there is a certain gap. Therefore, China's ultra-pure silicon development potential is great, long way to go.
Why is the current era known as the silicon era? At the Seventh International Conference on crystalline silicon production, scientists called the era of silicon. Why does silicon mention such a high position? This is because the world today is in the era of information from the industrial age. In the industrial age, the lead is steel, so steel production marks a country's economic and military strength. In the information age, the lead is the semiconductor material - silicon. There are many varieties of semiconductor materials, but there are not many varieties of industrial production, mainly silicon, germanium, gallium arsenide and gallium phosphide, which accounted for about 90% of the total semiconductor material production. This is why people call the times now the era of silicon.