What is High Purity Quartz?
High-purity quartz refers to quartz and its products with high SIO2 purity and very low content of impurities, which are widely used in semiconductors, photovoltaics, optical fibers, precision optics, advanced lighting equipment, new glass and other industries. However, due to the different industries that require different quality quartz, there is no universal quality evaluation index for high-purity quartz. Different people have different definitions. Early studies believed that the impurity content of high-purity quartz should be less than 50-10-6, that is, the purity of SiO2 should be greater than 99995% of the quartz is high-purity quartz. The Norwegian Geological Survey put forward more detailed indicators, requiring that not only the total mass of impurities should be less than 5 parts per 100,000, but also the content of Al should be less than 3 parts per 100,000, the content of Ti should be less than 1 part per 100,000, the content of Na and K should be less than 8 parts per million, the content of Li and Ca should be less than 5 parts per million, the content of Fe should be less than 3 parts per million, the content of P should be less than 2 parts per million, and the content of B should be less than 1 part per million. In 2014, according to the needs of the market industry, Flook proposed a new quality index, which considered the purity of SiO2 to be 99Quartz with 95% and a total impurity content of less than 5/10,000 is high-purity quartz, with a purity of 995%~99.8% quartz can meet the requirements of semiconductor filler, optical fiber, LCD screen production industry, and the purity is less than 995% quartz can be used in the clear glass industry.
Wang Ling scholars in China believe that the purity of SiO2 is greater than 999% quartz is high-purity quartz. In recent years, the emerging new glass industry such as photovoltaic glass and ultra-clear float glass has reduced the purity requirements for SiO2. Therefore, based on different index systems, considering the quality of raw material ores, testing methods, existing purification processes and industry quality requirements, the standard of high-purity quartz adopted in China is: SiO2 purity is greater than 999% quartz.
Quartz is often doped with trace impurities in the process of natural crystallization, mainly gangue minerals, inclusions, lattice impurities, etc. Like our common river sand and natural sand, there are too many impurities, and the silicon content of river sand is generally 65% to 85%, and the silicon content is too low to be used to produce chips. The type and content of impurity elements will affect the performance of quartz, for example, the presence of Al will affect the light conduction rate in quartz, Fe, Mn and other metal elements reduce the light transmittance of quartz, P and B content of quartz can not be used in the photovoltaic industry, so in the production of high-purity quartz, the raw material ore must be purified, as far as possible to reduce the content of AL, K, NA, LI, CA, MG, FE, MN, CU, CR, NI, B, P and other impurities.
Compared with ordinary glass, ultra-clear glass is crystal clear, high light transmittance, and has a very low iron content (Fe2O3 mass fraction does not exceed 150 10-6), which is only 1 10 of ordinary glass, or even lower. And ultra-clear glass is more safe, its self-explosion rate is only about 1/10,000, far lower than ordinary glass (self-explosion rate is about 3/1000), especially suitable for the construction of important buildings and high-rise buildings, such as the Beijing Olympic Games "Bird's Nest", "Water Cube" stadiums, Shanghai World Expo "China Pavilion", as well as Beijing National Centre for the Performing Arts, Nanjing China Art Center, etc. Therefore, in terms of impurity element content and silicon content requirements, the new glass industry and semiconductor industry will be more stringent and demanding.
Strictly speaking, high-purity quartz is not a mineral, but a product purified by crystal, vein quartz, quartzite, granite pegmatite and other ores as raw materials. This high-purity quartz sand does not exist in nature and needs to be mined and purified from quartz ore before it can be used in semiconductor manufacturing. Therefore, deposits that can be purified to produce high-purity quartz are called high-purity quartz raw material ores. The most ideal choice for the preparation of high-purity quartz sand is the raw material of high-purity quartz ore, quartz or quartzite are common, but high-purity quartz ore, especially high-purity quartz ore with economic mining value, is very rare.
High-purity quartz sand is an indispensable raw material for chip manufacturing and the material basis for high-end products in the silicon industry, while high-purity quartz raw material ore is extremely scarce. China is rich in siliceous resources, but most of the deposits are ordinary silica mines, which are used for ordinary glass, stone, construction sand, etc. At the same time, limited by the quality of the ore, the products produced are mainly low-end high-purity quartz. For high-purity quartz sand, raw ore and high-end quartz products, a large number of imports are relied on every year. Therefore, we must have an understanding of the distribution and development status of global high-purity quartz raw material ores. At present, high-purity quartz raw material deposits are mainly distributed in 7 countries, including the United States, Norway, Australia, Russia, Mauritania, China, and Canada. In addition to China, the Spruce Pine mine in the United States has the largest high-purity quartz raw material resources, exceeding 10 million tonsThe smallest resource is the Drag mine in Norway, with only 2670,000 tons (Wang Jiuyi, 2021;Table 1).
Distribution of high-purity quartz raw material ores in seven major countries in the world.
United States. 1.1 Spruce Pine Deposit.
The Spruce Pine high-purity quartz feedstock mine is located in Spruce Pine, Mitchell County, western North Carolina, USA. The mining area has a long mining history of more than 100 years. The content of impurity elements in quartz is very low, and after mechanical and chemical purification, the high-purity and ultra-pure quartz prepared are mainly used in semiconductor crystals, precision optical glass, photovoltaics, lighting and other industries. The mine supplies more than 90% of the world's demand for high-purity quartz sand, and is even the only place for a long time. In 2009, the BBC called it "the most strategically valuable square acre on earth" (Nelson, 2009).
1.2 Beauville deposits.
The Beauville Mine is located in Bovill, Latah County, Latah County, northern Idaho. According to the electron probe analysis, the purity of the quartz crystals in the ore is greater than 999%。In 2010, I-Minerals, Inc) completed the pre-feasibility study and developed SiO2 purity of 999%~99.997% high-purity quartz sand product. The proven resources of the deposit of potassium feldspar and quartz are 43780,000 tons, with a controlled resource of 88570,000 tons, a total of 132350,000 tonnes (i-minerals, 2020a). The high-purity quartz resources of Beauville mine are huge, and the difficulty of ore purification and processing is low. Using the traditional flotation purification process, high-purity quartz sand can be produced.
2.Australia.
Australia is rich in quartz resources, mainly found in northern Queensland, Victoria and Western Australia. Among them, the northern part of Queensland is the main high-purity quartz raw material mine, and many mineral deposits such as Lighthouse, Sugarbag Hill, White Springs, and Quartz Hill have been discovered.
2.1 lighthouse deposit.
The deposit is located in the Georgetown borough of northern Queensland. The town of Einasleigh, 16km southwest of the mine, is the nearest town. The lighthouse deposit is made up of two lighthouse-like peaks in the east and west, about 440 meters above the surface, hence the name. The ore in the mine is pure, translucent or milky white, lumpy, and nearly upright and filled in faults. The ore purity of the east and west ore bodies has been tested to be 999%, the content of the main impurity elements Al, Ti, Fe, P, Ca, etc. is low, and the purity can reach 99 after simple mechanical purificationMore than 95%, which proves that the lighthouse deposit is a high-quality high-purity quartz raw material mine.
2.2 Sugar Bag Mountain Deposits.
The deposit is located in the Georgetown district, about 25km northwest of Georgetown Town and 60km east of Lighthouse Mine. The ore quality is extremely high, with an in-situ SiO2 purity of up to 99More than 99%. The 2016 survey results indicated that the orebody was approximately 600m long with an average thickness of 20m, with drilling revealing an orebody depth of 60 to 80m (Alper, 2019). After sampling test and beneficiation and purification experiment, the purity of high-purity quartz sand can be prepared up to 99995%~99.999% to meet the quality requirements of the solar and semiconductor industries. At present, the sugar bag mountain deposit has not mined and produced high-purity quartz sand, but its proven and controlled resources are considerable in scale and can be mined in open pit.
2.3 White Springs and Quartz Mountain deposits.
From the town of Georgetown to the town of Mount Surprise (mtSurprise) is home to the White Springs and Quartz Hill mines along Highway 1. The deposits are all hydrothermal quartz vein-type. The ore quality of Baiquan Mine is excellent, and the purity of raw material SiO2 is 99More than 99%, the inferred high-purity quartz resource is 1.5 million tons. The purity of quartz mountain ore raw materials is greater than 995%, * high-purity quartz resources of 14 million tons, the resource scale is huge. The purity of high-purity quartz sand that can be produced by Baiquan Mine covers 9999%~99.999%, with an annual output of 30,000 tons of high-purity quartz sand, which is used in the photovoltaic and semiconductor industries. At present, the quartz mountain deposit has not yet entered the mining period.
2.4 Cresik deposits.
The deposit is located in the Creswick district in south-central Victoria, Australia. The deposit is of the gold mine tailings type, consisting of tailings from abandoned gold mines during the 19th century gold rush (Hughes, 2013). The ore is 6 200mm quartz gravel in the tailings, with excellent quality and low content of impurity elements, especially B and P content, which can be used in liquid crystal display, photovoltaic, semiconductor, optical glass and other industries. After being treated by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) using traditional mechanical and chemical purification processes, the purity of high-purity quartz sand SiO2 can reach 99995%。
3.Russia.
On the eastern side of the Russian Ural Mountains, there are two high-purity quartz deposits, the Saranpaul deposit in the subpolar Urals and the Kyshtym deposit in the South Urals. Among them, the Keshtem mine has a large scale and a high degree of development, and its high-purity quartz products are of excellent quality, which occupies a certain proportion in the international market.
3.1 Keshtrim deposit.
The Kyshtym deposit is located in Kyshtym, Chelyabinsk Oblast, Russia, 100 km southeast of Chelyabinsk. The deposit is of hydrothermal vein quartz type. The total length of the mining area is 15km, the width is 1 3km, the area is 20km2, and the quartz reserves are 1.36 million tons. The development of the deposit began in the 60-70s of the 20th century and has been more than 50 years now. In the early days, mining was mainly used in traditional industries such as building materials and glass. After 2011, mining began to produce high-purity quartz sand. The production capacity is expected to reach 6,000 tons per year in 2022, and the mine can meet the full capacity of production for 30 years.
3.2 Saranpaul deposits.
The Saranpaul deposit is located on the northwestern edge of the Berezovsky district of the Khanty-Mansi Autonomous Okrug-Ugra region, 85 km southeast of the village of Saranpaul. The deposit is of hydrothermal vein quartz type. The ore is translucent and transparent, with a vitreous luster. According to the 2014 exploration report of the tenement, the resource available for high-purity quartz is 330,000 tonnes (Development Corporation JSC, 2017). In addition, multiple unexplored quartz veins have been identified outside the tenement boundaries and prospective resources are likely to be more substantial.
4.Mauritania.
4.1 um Aquinina deposit.
The deposit is located in the province of Dakhlet Nouadhibou in western Mauritania, 130km west of the port of Nouadhibou. The deposit is of hydrothermal vein quartz type. The ore is light gray translucent, smooth and transparent, and the SiO2 content of some sampled ores is greater than 998%。The outcropping ore body at surface appears as a broken block of vein quartz gravel, which is overlain by a small amount of laterite. The inferred resource of quartz is 500.10 million tonnes (Feytis, 2010), but the amount of resource that could be used as a raw material for high-purity quartz is unknown due to the lack of drill validation and test assays and the necessary beneficiation experiments. No effective mining activities have been carried out to date.
4.2 Chami deposits.
The Chami deposit is located in the eastern part of Dakhlet Nouadhibou province, 20km from the um Aquinina mine. The genesis, ore type, surrounding rock, and occurrence characteristics of the deposit are similar to those of the um Aquinina mine, and the ore is translucent, smooth and transparent, and the ore SiO2 content is 98% 999%。Surface layer 2The proven reserves of high-purity quartz raw materials of ore bodies above 7m are 7250,000 tons; 2.The orebody below 7m can be extended to 8m, and there is room for further expansion of proven reserves.
5.Canada.
In the coastal zone of John Beetz Bay in southeastern Quebec, Canada, 10 north-east-south-west trending hydrothermal vein quartz ore bodies are exposed to the surface, namely the John Beetz high-purity quartz raw material mine. The results showed a SiO2 content of 98 in the ore7%~99.6%, and the average content of impurity elements B and P is less than 0., respectively25 10-6 and 02 10-6, which can be used to produce photovoltaic quartz crucibles. After accounting for mining losses, the high-purity quartz controlled resources of vein 2 and vein 9 surface orebodies are 174., respectively30,000 tons and 5070,000 tons, for a total of 2.25 million tons (Bathalon, 2014).
6.Norway. As a mountainous country with a long and narrow north and south, Norway is very rich in quartz resources, and has global quartz industry giants such as TQC and Elkem ASA. Based on the test data of quartz ores in China, the Norwegian Geological Survey also proposed a set of high-purity quartz quality evaluation indicators based on the content of lattice impurity elements (Müller et al.)., 2007; müller et al., 2012)。Currently, the Drager deposit in the north and the Nesodden deposit in the south are the main sources of high-purity quartz raw materials in Norway.
6.1 Drager deposit.
Located near the village of Drag on the west side of the Tysfjord fjord in Norrland County in northern Norway, the Drager mine consists of dozens of pegmatite-type quartz ore bodies distributed over a radius of 5 km2. The quartz crystal is pure, with an average particle size of 6mm, and the lattice impurity elements such as AL, TI, LI, and B all meet the quality requirements of high-purity quartz raw materials (Müller et al, 2012). Mining in the Drager mine began in 1907. Early mines mined potassium feldspar in pegmatites in an open-pit manner, and in 1996 they began mining to produce high-purity quartz sand for optics, lighting equipment, and photovoltaics.
6.2 Nesoden deposits.
The Nesoden mine is located in the city of Kvinnherad in the county of Hodaland in southwestern Norway. The ore body is approximately 580m long, 15m wide and extends 150m, with large quartz crystals in the ore. To date, no high-purity quartz mine has been mined. However, the mine has a considerable impact on the high-purity quartz sand and products industry. The ore deposit has a large amount of resources, and the reserve resources of high-purity quartz in the mining area are quite abundant. The Kvalvik hydrothermal vein quartz mine has also been discovered in the northern section of the fault zone, with an inferred resource of 700,000 tonnes, and its ore quality is similar to that of the Nesoden mine, which can be used as a high-purity quartz feedstock.
7.China. In recent years, some quartz sand mining enterprises in China are striving to develop the purification process of high-purity quartz and have made breakthroughs. High-quality hydrothermal vein quartz from Qichun in Hubei, Donghai in Jiangsu, Jingde in Anhui and Taihu Lake may have the potential for high-purity quartz raw materials (Jiao Lixiang, 2019). The Lingqiu Mountain Quartz Mine is located in Hengche Town, about 20km northwest of Qichun County, Hubei Province. Drill hole sampling results show that the ore is almost entirely composed of quartz, with a crystal size of 1 2 mm. Ore SiO2 purity 9935%，al2o3＜0.22%，fe2o3＜0.02%。At present, the Lingqiushan quartz mine adopts open-pit mining, and its designed mine scale is 1 per year50,000 tons of ore.
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The 2nd Anhui International Quartz Industry Conference and Exhibition 2024.