silicon product and China's silicon smelting industry situation
What is a silicon product?
The silicon content is between 14% and 99%. The rest are impurities or another major element. The alloy obtained by smelting is commonly known as a silicon product. Usually include industrial silicon, ferrosilicon, silicon germanium, silicon carbide, silicon calcium and the like. The most commonly used are industrial silicon and ferrosilicon.
Smelting any kind of silicon product must involve the ore material. Mining can damage forests and vegetation. At the same time, the smelting process will also produce a lot of pollution. It belongs to the metallurgical industry that consumes resources, has high pollution and has low technical content.
Therefore, developed countries generally do not produce. Mainly rely on imports. Due to the wide use of silicon products, it is determined that its largest consumer is developed countries. Therefore, in addition to their own consumption, most of the silicon products produced in developing countries are used for export in exchange for foreign exchange.
Smelting silicon products must have two basic conditions:
1. A place with strong environmental purification ability.
2. Rich low-cost power supply. Because silicon is a high-energy industry. Taking industrial silicon as an example, the average power consumption per ton of finished products is 12,000 degrees. It is usually only possible to use low-cost hydropower as a source of energy.
Due to heavy pollution, high-energy silicon metallurgical enterprises can only be distributed in remote, hydropower-rich areas. Due to the power shortage, in the dry season, the production is often reduced or stopped due to power cuts.
China's silicon smelting industry situation
The Sanming area of Fujian is the first place in China to produce silicon products such as industrial silicon. Due to the lack of hydropower and over-exploitation of resources in recent years, the current scale of silicon smelting in Fujian is mostly small.
In the past five years, Guizhou and Yunnan have become China's largest silicon production bases by utilizing their abundant hydropower resources. In particular, Guizhou's production accounts for more than 50% of the country's total. Sichuan, Hunan, Jiangxi, Xining, Inner Mongolia, and Northeast China are also the places where silicon products are produced.
In addition to individual small factories, silicon iron furnaces are now above 6300KVA. With the country's rectification of the ferroalloy industry and environmental protection requirements, small-capacity electric furnaces and furnaces that fail to meet environmental protection requirements will inevitably be eliminated.
Silicon product use
1. Industrial silicon, commonly known as metal silicon or crystalline silicon. Strictly speaking, industrial silicon is not a ferroalloy industry. It is customary for the smelting of industrial silicon to be carried out using a submerged arc furnace. Industrial silicon is divided into the ferroalloy industry.
Industrial silicon refers to pure silicon products containing silicon in an amount of 98.5% or more. Among them, the three impurity contents of iron, aluminum and calcium are divided into sub-categories. Such as 553, 441, 331, 2202 and so on.
Among them, 553 represents that the industrial silicon contains less than or equal to 0.5% iron, aluminum content is less than or equal to 0.5%, and calcium content is less than or equal to 0.3%. 331 industrial silicon means iron is less than or equal to 0.3%, aluminum is less than or equal to 0.3%, and calcium is less than or equal to 0.1%. And so on. For customary reasons, 2202 is also abbreviated as 220. Represents calcium less than or equal to 0.02%. The industrial silicon at the beginning of 2 is also called chemical silicon.
The main use of industrial silicon: industrial silicon as an additive to non-ferrous based alloys. Industrial silicon is also used as an alloying agent for demanding silicon steel. Smelting deoxidizers for special steels and non-ferrous alloys. Industrial silicon can be drawn into single crystal silicon after a series of processes. For the electronics industry. Used in the chemical industry to produce silicones and the like. Therefore it has the name of magic metal. It is very versatile.
Industrial silicon is added to metals such as aluminum and iron to improve or enhance the excellent properties of the metal. Automotive aluminum has a considerable demand for industrial silicon. Therefore, the development of the automobile industry in a region and country has a direct impact on the rise and fall of the industrial silicon market.
Industrial silicon is further purified to 99.999% or more to form polycrystalline silicon. It is then mechanically cut into silicon single wafers. A large number of applications in the electronic information industry. Such as various types of IC cards, VCD cards, DVD cards, and so on.
At present, China's purification technology is not very mature. Basically rely on Japanese imports. That is, Japan imports industrial silicon raw materials from China at a price of about 7,300 yuan to 7,600 yuan per ton. Further purification will be produced at relevant prices in China for about RMB 300,000 per ton.
In terms of cutting monocrystalline silicon wafers, there is still a certain technological gap between China and developed countries. Especially in the post-finishing of silicon wafers and surface coatings, the gap is quite large.