Quartz has different application fields according to its content, of which 99.5% ~ 99.99% is used in light source industry, more than 99.99% is used in high-end optical devices and laser devices, and 99.995% ~ 99.9999% is used in semiconductor, photovoltaic and other industries.

What is high purity quartz?

High purity quartz is a high-tech strategic mineral resource that is scarce in the world and in China. It is an irreplaceable mineral raw material for manufacturing high-tech quartz glass and a scarce common high value-added mineral resource required by strategic emerging industries. There is no clear standard for the concept and classification of high-purity quartz in China. Based on the viewpoints of researchers and the current international technical level, we can integrate the purity ω (SiO2)≥3 N～5 N、 ω (Fe2O3)＜10 × The quartz of 10-6 is called high-purity quartz, and the quartz of 6 N to 7 n is called ultra-high-purity quartz.

High purity quartz products are widely used in high-tech industries such as electric light sources, optical fiber communications, solar cells, semiconductor integrated circuits, precision optical instruments, medical utensils, aerospace and aviation. They play an important role in a country's scientific and Technological Development and are resources of strategic significance.

Some high purity quartz products

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High purity quartz has different application fields according to its content, of which 99.5% ~ 99.99% is used in light source industry, higher than 99.99% is used in high-end optical devices and laser devices, and 99.995% ~ 99.9999% is used in semiconductor, photovoltaic and other industries.

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(1) semiconductor industry

The semiconductor industry is the foundation of the global information industry. The wide application of semiconductor products has promoted the advent of the era of information and intelligence. Chip manufacturing mainly consists of single crystal growth, wafer processing and manufacturing, integrated circuit wafer production and later packaging. Crystal growth requires quartz crucibles and quartz devices. In the etching, diffusion, oxidation, annealing and other steps of wafer processing, a large number of auxiliary materials such as quartz glass, such as high-purity quartz products such as quartz sheets, quartz rings and quartz boats, are required. The diffusion step is to diffuse elements such as boron and phosphorus into the silicon wafer in a quartz furnace tube at about 1000 ℃. China has issued a series of industry standards, such as transparent quartz glass tubes for semiconductors, transparent quartz glass devices for semiconductors and transparent quartz glass rods for semiconductors.

(2) optical fiber industry

The communication industry is the "information industry expressway". The quartz fiber made of high-purity quartz is used as the high-speed intelligent "pipeline" of information, which will provide basic guarantee for Industry 4.0 and Internet +. Quartz optical fiber is a very fine filament with a diameter of less than 8mm. Digital data is transmitted through optical fiber in the form of light, which is widely used in the field of communication, microelectronics and optoelectronic devices. Compared with other transmission media (cable or copper wire), quartz optical fiber has stronger anti electromagnetic interference ability, corrosion resistance, better bandwidth and capacity, and less resource loss. According to different materials, quartz glass optical fiber can be divided into pure quartz glass optical fiber and doped quartz optical fiber. Doped quartz fiber mainly includes rare earth doped quartz fiber, fluorine doped quartz fiber and nitrogen doped quartz fiber. Rare earth doped fiber has good laser performance, and fluorine doped quartz fiber and nitrogen doped quartz fiber have radiation resistance. By adjusting the structural design, refractive index distribution, doping process, pre irradiation treatment and post irradiation treatment of optical fiber, its anti space radiation performance can be improved. Therefore, optical fiber is not only used in the traditional communication field, but also in the special high-energy radiation environment, such as the internal detection of fusion reactor, the amplifier of highly distributed data network in aerospace, the broadband super light source of fiber optic gyroscope, and the fiber laser that provides signals of fission reactor. In addition, high-purity quartz also has certain optical characteristics, which can form polarized laser beams. Using high-purity quartz as a window, a fiber laser is manufactured with prisms, filters and timing devices. High quality quartz crystal is also used in prisms and lenses of optical instruments. It can be seen that the optical fiber made of high-purity quartz has very high added value.

(3) photovoltaic industry

Photovoltaic is the abbreviation of solar power generation system. As a green industry with sustainable development, photovoltaic is receiving more and more attention. Its application cost has been greatly reduced in recent years, and it is rapidly popularized in the civil field. High purity quartz is one of the key raw materials in the photovoltaic industry. The main application forms are quartz crucibles, quartz tubes and various quartz equipment. The solar quartz crucible is a consumable used in the photovoltaic industry. It is a consumable container for pulling large-diameter single crystal and polycrystalline silicon products. The use temperature is about 1500 ° C and the use frequency is only once. China has issued a series of industry standards, "quartz boat for solar cell silicon" and "quartz glass diffusion tube for solar cell silicon". The quartz boat and quartz glass diffusion tube for solar cell silicon wafer shall meet the quality requirements of Grade T products, as shown in the following table.

Impurity content requirements of quartz boat and quartz glass diffusion tube for solar cell silicon wafer

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(4) optics and light source

Optical quartz glass is widely used in the optical field because of its high temperature resistance, corrosion resistance and low expansion rate. High purity quartz glass is used for the production of telescope lenses, laboratory optical equipment, communication equipment, diffractive lenses, projection displays, scanning equipment, printers, optics, lasers, cameras, hyperplane TV screens, flame control equipment, etc. Electric light source glass can be divided into potassium calcium glass, lead containing silicon glass, boron containing silicon glass, aluminum containing silicon glass and quartz glass according to its chemical composition. Electric light source products produced with high-purity quartz glass as raw materials include high-pressure mercury lamps, metal halide lamps, halogen dock lamps, xenon based lamps, automobile lamps, etc., which can withstand high temperatures and provide high transmission characteristics.