1. Overview
Quartz sand, quartz sandstone and quartzite in nature are collectively called siliceous raw materials and are widely distributed. Quartz is the main mineral component of siliceous raw materials. It is a mineral resource with very stable physical and chemical properties. It is widely used in industries such as optics, glass, electronics, chemistry, and refractory materials.
2. Rock Mineralogical Characteristics
The main mineral component of siliceous raw material ores is quartz, and the secondary minerals include various types of feldspar, rock debris, heavy minerals (garnet, Tourmaline, pyroxene, amphibole, fine stone, topaz, epidote, ilmenite, etc.) and mica, chlorite, clay minerals, etc. Quartz is the most common mineral formed by SiO2 alone in nature, including low-temperature quartz of the trigonal system (α-quartz) and high-temperature quartz of the hexagonal system (β-quartz). Most of the common ones are low-temperature quartz, generally referred to as quartz. Quartz aggregates are in the form of clusters or granular, massive, stalactite, or nodule shapes, without cleavage, with shell-shaped fractures, glass luster, and the fracture often has a grease luster. Pure ones are colorless and transparent, but most of them are gray, yellow to orange, purple, deep purple, pink, gray brown, brown, and black due to containing trace pigment ions or finely dispersed inclusions, or having color centers, and the transparency is reduced. . Streaks white. Density 2.65～2.66g/cm3. Mohs hardness 7. The refractive index is 1.533~1.541, the birefringence difference is 0.009, and the dispersion is 0.013. Its chemical, thermal and mechanical properties have obvious anisotropy, it is insoluble in acid and slightly soluble in KOH solution. Quartz crystal has optical activity, pyroelectricity, and piezoelectricity. There are often solid, liquid and gas inclusions in quartz crystals.
Quartz sand refers to various sands with an absolute dominant quartz component, such as sea sand, river sand, lake sand, etc. Quartz sandstone is a consolidated sandy rock with a quartz and siliciclastic content generally above 95%. The accessory minerals are mostly feldspar, mica and clay minerals, and the heavy mineral content is very small. Common heavy minerals include tourmaline, rutile, magnetite, ilmenite, etc. The cement is generally siliceous. Quartzite is a metamorphic rock formed by metamorphism of quartz sandstone or other siliceous rocks.
The grade of raw ore of siliceous raw materials in my country is not high. Generally speaking, the quality of rock ore is better than sand ore, quartzite is better than quartz sandstone, northern sandstone is better than southern sandstone, and marine sand is better than continental sand. good. The chemical composition of quartz sandstone and quartzite ores is relatively stable. The SiO2 content is generally greater than 97%, the Al2O3 content is generally 0.4% to 1.3%, and the Fe2O3 content is generally 0.04% to 0.39%. The chemical composition of quartz placer varies greatly from place to place, with SiO2 content of 82% to 99%, Al2O3 content of 0.2% to 6%, and Fe2O3 content of 0.07% to 1.38%. The main harmful impurities in siliceous raw material ores are iron compounds. The Fe2O3 content in quartz rock is 0.12% to 1%, most of which are less than 0.2%; the Fe2O3 content of quartz sandstone is 0.06% to 1.12%, most of which is less than 0.3%; the Fe2O3 content of quartz sand is 0.1% to 2.5%, most of which is less than 0.6%. The Al2O3 content is related to the feldspar content, with a low of 0.1% and a high of up to 10%.
3. Application
Silicon raw materials are widely used in glass, refractory materials, ceramics, casting, petroleum, chemical industry, environmental protection, grinding and other industries.
1) Metallurgical industry: Quartz has high refractory properties and is mainly used for manufacturing refractory materials (silica bricks), smelting silicon alloys (ferrosilicon, silicon manganese, silicon chromium) and as flux. Pure crystalline silicon can be produced. Crystalline silicon is the main raw material for the production of single crystal silicon, and can also be used to produce silicon aluminum and organic silicon. Sand used for molding in the foundry industry. In the metallurgical industry, it can be used as smelting additives, fluxes and various ferrosilicon alloys. In the refractory material industry, it can be used as high-temperature bricks for kilns, ordinary bricks, refractory materials, etc.
2) Glass industry: It is the main raw material for making glass, and can also be made into refractory bricks for the lining of glass melting furnaces. Glass products are made of siliceous rock (sand) as the main raw material, generally accounting for about 70% of the raw material composition. Dolomite, limestone, feldspar, soda ash, Glauber's salt, carbon powder and other ingredients are added, and through melting, shaping, annealing, cutting, etc. Made with craftsmanship.
3) Cement industry: Quartz can be used as a correction material for Portland cement, and sand can also be used as cement ingredients, aerated concrete, ordinary products, etc.
4) Construction industry: It can be used as an important building cornerstone, road filling stone and railway ballast.
5) Chemical industry: It can produce various silicides, silicates and nitrates, and those with good quality can be used as fillings in acid-resistant sulfuric acid towers. It can also be used to produce lead silicate, potassium silicate, sodium metasilicate, water glass, silica gel, desiccant, petroleum refining catalyst, exterior wall paint, road line paint, etc.
6) Abrasive materials: Quartzite and quartz sandstone can be made into grinding stones, oil stones, sandpaper, silicon carbonate and other abrasive materials; quartz sand is also commonly used for sawing stones, polishing glass, grinding metal products and stone tools The surface of the product is also used to polish jewelry.
7) Sandblasting abrasive: Quartz sand can be used as sandblasting abrasive to remove oxide scale on the surface of various aluminum alloy parts and perform surface treatment on granite and marble.
8) Other industries: can be used for enamel and ceramic raw materials, water treatment. Pure ones are widely used in insulating materials, decorative materials, radio industry, optical instruments, resonators, oscillators, filters, communication networks, wireless data transmission, high-speed digital data transmission, infrared detectors, thermoelectric laser calorimeters, night Visual instruments, spectrometer receivers, medical quartz lamps, ultrasonic technology, modern defense and cutting-edge technology.
IV. Geological Characteristics
There are five main types of siliceous raw material deposits in my country.
1) Sedimentary metamorphic quartzite deposits. Most of them were generated in the structural subsidence zone at the edge of the platform, belonging to coastal-foreshore facies deposits, and were later formed by diagenesis and slight shallow metamorphism. Examples of this type include quartzite deposits such as Xiaopingdingshan in Benxi, Liaoning and Laoqingshan in Fengyang, Anhui. Most of them are large in scale. The ore body is layered, tens to hundreds of meters thick, contains little or no interlayers, and the interlayers are regularly distributed. The mineral composition of the ore accounts for more than 95% to 99% of quartz, and contains little or no feldspar, clay minerals and rock debris. Common trace minerals include mica, tourmaline, zircon, rutile, magnetite, apatite, etc. . Silica cementation, secondary iron staining is not serious. Chemical composition of ore: SiO2 96.42% ~ 99.78%, generally not more than 97%; Al2O3 0.14% ~ 1.5%; generally less than 1%; Fe2O3 0.08% ~ 0.2%, generally less than 0.15%. The quality of the ore is good, and the particle size is mainly fine, generally between 0.2 and 0.4mm.
2) Sedimentary quartz sandstone deposits. Generated in the continental margin and seaside at the edge of ancient continents or ancient uplifts, they are mostly intertidal to supratidal zone deposits. Belonging to this type are quartz sandstone deposits such as Qingmingshan in Suzhou, Jiangsu, Lei Zipai in Xiangtan, Hunan, and Wanchao in Kaili, Guizhou. The scales are mainly large. The ore body is layered, usually with 2 to 3 or 4 to 5 layers of ore. The layer thickness is usually tens of meters, but rarely exceeds 50 m. The shape of the ore body is still stable, mostly containing layered or lens interlayers, and the distribution is irregular. The mineral composition of the ore accounts for more than 95% of quartz content. The particle size is mainly 0.2 to 0.5 mm, and it is angular to sub-round. It contains a small amount of feldspar, clay minerals and rock debris. Common trace minerals include mica, tourmaline, Zircon, rutile, magnetite, ilmenite, hematite, apatite, etc. Siliceous and clayey cement, with varying degrees of secondary iron staining. Chemical composition of ore: SiO2 95.58% ~ 99.75%, generally greater than 96%; Al2O3 0.29% ~ 3%; generally less than 1.5%; Fe2O3 0.01% ~ 0.24%, generally less than 0.2%. The raw ore quality of this type of ore is generally inferior to that of quartzite ore, and the quality of ore in different deposits also varies greatly. However, the selectability of the ore is generally better, and high-quality concentrate can be obtained after beneficiation. In addition, the Mesozoic quartz sandstone deposits distributed in Jiangjin, Yongchuan, Sichuan, and Dangyang, Hubei, are inland lacustrine sedimentary deposits.
3) Marine sedimentary quartz sand deposits. The deposits are distributed along the coast and belong to coastal foreshore subtidal-intertidal zone sedimentary sand deposits. Belonging to this type are quartz sand deposits such as Fujian Dongshan Wulong, Guangdong Huidong Bijia, Guangdong Yangdong Dagou, Guangdong Leizhou Qishui, Hainan Dongfang Basuo, Guangxi Beihai Baihutou, Shandong Rongcheng, and Xukou. The size of the deposits is mostly large. Mineral deposits are generally tens of centimeters to about 1m above sea level, and the beach surface or mineral layer slopes toward the sea at a small angle. The bottom of the mineral seam is organic-rich sandy clay of coastal intertidal phase. The ore body is layered, several meters to more than ten meters thick, containing lens interlayers, mostly organic clay sand.
Quartz accounts for more than 90% to 99% of the mineral composition of the ore. It is mostly medium and fine grained, with uniform particle size and good sorting. It contains a small amount of feldspar, clay minerals and rock debris. Common trace minerals include mica, tourmaline, zircon, Rutile, magnetite, ilmenite, white titanite, garnet, monazite, etc., some contain chromium spinel, with varying degrees of secondary iron staining. Chemical composition of ore: SiO2 92.12% ~ 98.45%, generally greater than 92%; Al2O3 0.1% ~ 3.5%, generally less than 2.5%; Fe2O3 0.01% ~ 0.21%, generally less than 0.2%. The quality of the ore is good. Although there are changes in each producing area, there is a certain regularity. The mineral composition, chemical composition and particle composition are closely related.
4) Fluvial and lacustrine sedimentary quartz sand deposits. Distributed on both sides of the middle reaches of the Yellow River, quartz sand deposits such as Hujingzui in Lanzhou, Gansu and Sidaoquan in Etuoke Banner, Inner Mongolia, belong to riverside floodplain deposits; distributed at the junction of Yihe, Shuhe and Luoma Lake in Jiangsu and in the foothills of Maling Mountain Quartz sand deposits such as Baimajian and Chenggang in Xinyi, Suqian, Jiangsu belong to river delta phase deposition. The ore seam has cross-bedding development, complex structure, large thickness changes, poor ore quality, and weak clay cementation. After elutriation, the sand and mud are separated. After further beneficiation and separation of feldspar, high-grade quartz sand concentrate can be obtained. Quartz sand deposits such as Turjishan, Ganqika, and Zhanggutai, which are distributed in the Tongliao Basin in the northeast, belong to fluvial and lacustrine facies sediments. The distribution of the mineral layers is stable, the ore material composition and particle size are uniform, the internal structure of the mineral layers is simple, and the interlayers mostly contain organic matter. The black and gray clay sand layers were aeolian accumulation after the Holocene basin rose up, forming the current aeolian landform landscape. Deposits range in size from small to large. Ore bodies are irregular or lenticular, generally several meters thick, containing lenticular interlayers composed of different ore bodies or clay layers, with irregular distribution. Quartz accounts for 80% to 95% of the mineral composition of the ore, and contains more feldspar, clay minerals and rock debris. Common trace minerals include mica, tourmaline, zircon, rutile, magnetite, ilmenite, and pomegranate seeds. Stone, epidote, chlorite, etc., with varying degrees of secondary iron staining. Chemical composition of the ore: SiO2 81.70% ~ 98.46%, Al2O3 1.5% ~ 9.29%, Fe2O3 0.07% ~ 1.03%.
5) Lacustrine sedimentary quartz sand deposits. It is mainly the modern lakeside facies quartz sand deposits distributed in Hukou, Yongxiu and other places on the east bank of Poyang Lake in Jiangxi Province, and is still receiving lacustrine deposits. Deposits range in size from small to large. The ore body is layered, several meters thick, and the interlayers are distributed regularly. Quartz accounts for more than 90% of the mineral composition, and contains more feldspar and rock debris. Common trace minerals include mica, tourmaline, rutile, magnetite, garnet, epidote, chlorite, etc. With varying degrees of secondary iron staining. Chemical composition of the ore: SiO2 92% ~ 95.54%, generally 93%; Al2O3 0.1% ~ 5.5%, generally 2.5%; Fe2O3 0.07% ~ 0.32%, generally 0.16%.
5. Distribution of mineral deposits
1) Quartz sand deposits. Distributed in Hainan, Jiangxi, Guangdong, Fujian, Inner Mongolia, Jilin, Guangxi, Jiangsu, Shandong, Liaoning, Gansu, Heilongjiang, Xinjiang, Ningxia and other provinces and regions. Hainan accounts for 49.69%, Jiangxi accounts for 11.38%, and Guangdong accounts for 11.14%. Quartz sand deposits in my country are mostly distributed in Quaternary modern coastal sediments in the east and along the coast of Jiaodong Peninsula. The main metallogenic belt is the quartz sand deposit distribution belt on the south coast, starting from southern Fujian in the north, including Huidong, Yangxi, Leizhou and Hainan in Guangdong, and ending in Beihai, Guangxi, is the main development and utilization target of sea sand mines in my country. Fluvio-lacustrine quartz sand deposits are mainly distributed in the Quaternary System of the Tongliao Basin at the junction of Inner Mongolia, Jilin, and Liaoning. The distribution area of ??Tongliao quartz sand deposits includes the West Liaohe-Liuhe area. The deposits are mainly concentrated along the Dazheng Railway. It is one of the main supply bases of glass siliceous raw materials in northern my country. Fluvial alluvial quartz sand (rock) deposits are mainly distributed along the middle reaches of the Yellow River and in the Neogene area in Suqian, Anhui. Lacustrine sedimentary quartz sand deposits are found in the first or second terraces on the east bank of Poyang Lake from Hukou to Yongxiu in Jiangxi. In the fourth series, some of the deposits have been utilized by its nearby glass factories.
2) Quartz sandstone deposits. Distributed in Shandong, Sichuan, Hebei, Jiangxi, Hunan, Jiangsu, Zhejiang, Guizhou, Shanxi, Hubei, Yunnan, Ningxia, Jilin, Guangxi, Shaanxi, Beijing, Xinjiang, Gansu, Inner Mongolia and other provinces (regions, cities). Shandong accounts for 28.16%, Sichuan accounts for 11.83%, and Hebei accounts for 9.03%.
my country’s quartz sandstone deposits are mainly produced in the sedimentary cover of the Yangtze Platform. The production layers are mainly Devonian, followed by Sinian, Cambrian, Jurassic and Triassic. and Neogene, mineral deposits are often found in shallow marine facies or marine-continental alternating facies sediments. The main mineralization area is the quartz sandstone distribution area in the Yangtze River Basin, starting from Jiangsu and Zhejiang in the east, to Hubei in the west, extending to Hanzhong, Shaanxi in the north, and Hunan and Guizhou in the south. There are many mineral deposits with large scale and good quality. In addition, several large quartz sandstone deposits have been discovered in the Cambrian system in Yinan, Cangshan and other places in Shandong, forming another quartz sandstone mineralization area.
3) Quartzite deposits. Distributed in Qinghai, Liaoning, Shaanxi, Anhui, Shandong, Henan, Gansu, Fujian, Shanxi, Zhejiang, Beijing, Inner Mongolia, Jiangsu, Xinjiang, Jiangxi, Jilin and other provinces (regions, cities). Qinghai accounts for 69.25%, Liaoning accounts for 12.45%, and Shaanxi accounts for 7.80%.
my country’s quartzite minerals are mainly produced in the secondary subsidence zone of the North China Platform and the Qilian Fold Belt, and are also distributed in the Yangtze Platform. The ore-bearing layers are mostly Precambrian, and some are Silurian, Devonian system. The main metallogenic areas are the quartzite (quartz sandstone) distribution areas in Liaoning, Hebei, and Henan, starting from Baishan in Jilin, passing through Liaoning, Hebei, Beijing, and Shanxi and ending in Henan. They are roughly distributed in the northeast direction and are strictly affected by the Sinian ore-bearing strata. control; another mineralization area is the Xining-Bohai Bay quartzite (quartz sandstone) distribution belt. The mineral belt is distributed around the western edge of the Sino-Korean platform. The scale and quality of the deposits are not as good as the former, but they are the main mining and utilization targets in northwest my country. The main metallogenic belt of sedimentary metamorphic quartzite is the Liaonan-Fengyang quartzite distribution belt, and the deposits are found in Zhuanghe, Liaoning, Pixian, Jiangsu, Fengyang, Anhui and other places. See Figure 2-46-1 for details.
Figure 2-46-1 Schematic diagram of the distribution of siliceous raw material deposits in China
6. Available resources
As of the end of 2005, there were 228 identified mineral deposits in my country , the identified resource reserves are 47×108t (Table 2-46-1). From a quantitative point of view, my country's supply of siliceous raw material minerals exceeds demand. In addition to meeting domestic needs, some are exported; from a variety point of view, high-quality siliceous raw materials are insufficient, which to a certain extent affects the stability and improvement of flat glass product quality. .
Table 2-46-1 Distribution of identified resource reserves of different types of siliceous raw material deposits in various regions in China (104t, ore)
(According to the Ministry of Land and Resources’ National Mineral Resources Resource Reserve Bulletin, 2005)