Quartz resource is an important non-metallic mineral resource, which can be used as raw materials for processing glass sand and industrial silicon. It is an important raw material for metallurgy, chemical industry, glass, ceramics, casting, rubber and other industries. industry and the cornerstone of the development of silicone new material industry.
There are various causes of quartz deposits in nature. At present, the common industrial types of quartz deposits available for development and utilization include natural crystal, quartz sandstone, quartzite, vein quartz, powder quartz, natural quartz sand and granite quartz.
1. Natural crystal
Natural crystal is a large transparent quartz crystal mineral, the main component is silicon dioxide. Most crystals are naturally grown in caves, rock cracks, joints, and faults. The growth conditions are relatively harsh, and four conditions must be met at the same time: ample growth space, able to provide hydrothermal fluid rich in silica, and a certain temperature and stress, enough time to grow. my country’s natural crystal resources are widely distributed, among which the East China Sea in Jiangsu is the most abundant.
Natural crystal deposits have small reserves, poor mining conditions, scarce resources, and high prices, which are difficult to meet the needs of large-scale industrial production. But because the natural crystal is rich in color, crystal clear, beautiful and pure, it is mainly used for carving various handicrafts at present.
2. Quartz sandstone
Quartz sandstone is a sandy sedimentary rock that has been consolidated by sedimentation. The content of quartz and siliceous clasts is generally >95%. The accessory minerals are mostly feldspar, mica and clay minerals, and the cement is generally siliceous. At present, my country’s quartz sandstone is distributed in all provinces, among which resources are abundant in Daguan, Yanjin, Yiliang in Yunnan and Muchuan in Sichuan.
Quartz sandstone deposits are generally large in scale, with stable geological occurrences and good mining conditions. At the same time, the ore hardness is generally relatively low, and the natural particle size is moderate, which is easy to crush and classify and large-scale industrial production. However, due to the complex composition of quartz sandstone cement, it is usually used in the production of daily-use glass sand, glass fiber, metal silicon, refractory materials, white carbon black, organic silicon and other fields.
Quartzite is usually a metamorphic rock formed by quartz sandstone or other siliceous rocks through regional metamorphism or thermal contact metamorphism. In addition to feldspar, mica and clay minerals, associated minerals often contain trace amounts of tourmaline and hematite and zircon etc. Compared with quartz sandstone, the ore of quartzite is denser and harder. my country’s quartzite resources are very rich, with a large amount of development and utilization, mainly distributed in Fengyang, Anhui and other areas.
The quartzite deposit has the advantages of large scale, stable geological occurrence, and good mining conditions. Large-scale industrial production of products in traditional application fields such as quartz plates with a SiO2 content of about 99%.
4. Vein quartz
It is mainly formed under the action of magma hydrothermal fluid, usually in a dense massive structure, and its mineral composition is single, almost all of which are quartz, and the SiO2 content is generally above 99%. Vein quartz deposits are generally small in scale, with steep occurrences, a thickness of several meters to tens of meters, and a length of tens of meters to hundreds of meters. A mining area may consist of one ore vein or multiple ore veins.
The resource reserves of vein quartz deposits are generally relatively small, and mining is relatively difficult. However, due to its low impurity content and stable resource quality, it is mostly used to prepare SiO2 99%-99.9% silicon micropowder and low-iron quartz. Sand, optical glass, semiconductor and other high-quality quartz products.
5. Powder Quartz
It is usually a sedimentary weathered deposit formed by the weathering and disintegration of siliceous parent rock under special geological structural conditions (temperature and humidity paleoclimate, gentle terrain paleogeography, hydraulic action, etc.), and the quartz content is usually 95% to 98%. can be as high as 99%.
This kind of deposits are widely distributed in southern my country, such as Guiding, Guizhou, Lianhua, Jiangxi, Yunfeng Mountain, East Yu, etc. Compared with quartzite and quartz sandstone, the scale of this type of deposit is relatively small. Its main advantages are high natural whiteness, natural looseness and porosity, easy ultrafine grinding and processing, and can be used as ceramic raw materials and silica powder fillers.
6. Natural quartz sand
Natural quartz sand is a kind of sandy quartz mineral raw material with quartz as the main mineral component formed by the long-term weathering of parent rocks such as granite, quartzite, quartz sandstone and vein quartz. Its associated minerals include feldspar, cuttings, Mica, clay minerals and heavy minerals such as zircon, tourmaline, ilmenite and hornblende are mainly marine sedimentary placer deposits and fluvial and lacustrine sedimentary placer deposits.
The scale of this type of deposit is generally large, and its main advantage is that it usually has a natural moderate particle size and angular shape factor, and is easy to mine. It is an ideal raw material for processing quartz sand products for casting. However, the disadvantage of this type of deposit is that there are many impurities. If the impurities are fully removed, it can be used All quartz products with SiO2 content of about 99% are processed.
7. Granite quartz
Refers to the quartz in large-grained granite or granite pegmatite (white granite) formed due to magmatic consolidation. The grade of quartz in this type of deposit is mostly about 25%, and the mineral impurities mainly come from the fluid inclusion-level lattice impurity elements in the quartz particles. This type of deposit is the main raw material for the production of high-purity quartz, currently mainly produced in Spruce Pine, North Carolina, USA.