High Purity Quartz – “Panda in Silica”
2022-11-10
Quartz is one of the most common minerals in nature. It is the scientific name of a group of minerals composed of silicon dioxide (SiO2). It is widely used in traditional industries such as glass, architecture, gemstone decoration and so on. Since the 1960s, emerging technologies such as computers, new materials, and new energy have put forward higher requirements for the purity of quartz products, and the concept of high-purity quartz was born.
High-purity quartz is an irreplaceable basic material in the development process of national strategic industries and pillar industries. It is indispensable and irreplaceable for high-tech industries such as semiconductor chips, solar photovoltaics, optical fiber communications, aerospace, precision optics and special glass. Important functional materials are mineral resources that are truly “stuck in the neck”. In nature, although quartz is widely distributed, high-purity quartz with high purity is very rare.
What is High Purity Quartz?
High-purity quartz is naturally formed (such as crystal) or purified and processed from relatively pure quartz raw materials. Due to the different quality requirements of quartz in different industries, there is no uniform quality standard for high-purity quartz in the world today. According to the quality requirements of quartz glass used in the semiconductor and photovoltaic industries, some scholars in Norway and the United States believe that the total impurity content of quartz should be less than 50 parts per million, that is to say, the purity of SiO2 must reach more than 99.995% to be called high purity quartz. Some scholars in my country believe that quartz with a purity of 99.9% or more than 99.99% SiO2 is high-purity quartz.
Generally speaking, the higher the purity of quartz, the lower the impurity element content, and the better the quality. This is because high-purity quartz has better properties such as high temperature resistance, corrosion resistance, low thermal expansion, high insulation and light transmittance, which can meet the quality requirements of high-tech industries such as semiconductor chips, solar photovoltaics, and precision optics.
Preparation of high-purity quartz
There are three main types of preparation methods for high-purity quartz, namely natural crystal grinding, deep purification of quartz minerals, and chemical processing and synthesis.
1. Natural crystal grinding
High-purity quartz was originally obtained by deep purification from primary and secondary natural crystals. The process of preparing high-purity quartz sand from natural crystals is relatively simple. The raw crystal ore is crushed, magnetic separation, flotation, acid leaching, drying, and roasting to obtain finished quartz sand.
2. Deep purification of quartz minerals
Due to the advantages of low price of natural quartz minerals, relatively abundant resources, and low pollution in the preparation process, currently high-purity quartz sand is mainly purified from quartz minerals.
The deep purification of quartz minerals is mainly to remove a small or trace amount of impurities and obtain high-purity quartz. According to the current level of technology, people can purify high-purity quartz from mineral resources such as vein quartz, quartzite, powder quartz and pegmatite, and even from the tailings of some metal mines. Among many quartz mineral deposits, granite pegmatite is the most ideal mineral for purifying high-purity quartz.
However, the global distribution of raw materials that can be processed into high-purity quartz is less distributed and uneven.
3. Chemical processing methods
In recent years, the research on the preparation of high-purity quartz by chemical synthesis has gradually attracted the world’s attention. At present, the chemical processing methods of high-purity quartz mainly include gas-phase synthesis method, chemical precipitation method, sol-gel method, and silicon tetrachloride liquid-phase hydrolysis method.
At present, the world’s major producers of high-purity synthetic quartz materials include Corning Corporation of the United States, Heraeus of Germany, Tosoh Corporation of Japan, Shin-Etsu Quartz Corporation of Japan, and Philippine in China.
High Purity Quartz Applications
Industries and fields such as semiconductors, optical communications, photovoltaics, optics, and electric light sources are important fields that support the development of strategic emerging industries, and are important guarantees for building major projects, improving people’s livelihood, and consolidating national defense and military industries, and occupy an important position in the construction of the national economy. , High-purity quartz is widely used in these industries and fields, and is a rare and common high-value-added mineral resource required by these fields.
Main Application Fields Of High-purity Quartz Products
(Note: ① means SiO2 content of 99.995%; ② means SiO2 content of 99.998%.)
| High Purity Quartz
product |
Main application field | main application | High Purity Quartz Grade |
| Quartz Crucible | semiconductor, Photovoltaic | Containers for the production of silicon crystals in the semiconductor and photovoltaic industries | ≥4N5①,
inner coating of quartz crucible> 4N8② |
| Quartz tube | Aerospace, weapons and equipment, semiconductor new electric light source, optical communication | Quartz fiber, quartz wool, quartz cloth, etc. produced with quartz tubes are used in the fields of aerospace and weaponry. It is used to make fairings, radomes, heat shields, wave-transmitting materials and high-temperature resistant materials; in the new electric light source industry, it is used to produce blister materials for lighting; in the optical communication industry, it is used to produce optical communication control rods; The semiconductor industry is used for the production of quartz diffusion furnace tubes. | ≥4N5① |
| Quartz rod | semiconductor,
Photovoltaic， New electric light source |
In the photovoltaic industry, it is mainly used for the production of single/polysilicon distillation towers, vaporizers and feed pipes and other instruments; the new electric light source industry is used for single-ended halogen lamps; the semiconductor industry is used for semiconductor quartz boat bases and Other auxiliary materials, etc. | ≥4N5① |
| quartz boat,
Quartz Ingot |
semiconductor,
Photovoltaic |
In the semiconductor industry, it is used for quartz bells, flanges, quartz flower baskets and other auxiliary materials, mainly in the silicon wafer diffusion process; in the photovoltaic industry, it is mainly used as consumables for silicon wafer production. | ≥4N5① |
