Quartz sand is an important industrial mineral raw material with a wide range of uses, including glass, casting, ceramics and refractory materials, metallurgy, construction, chemical, plastic, rubber, abrasive and other industries. More than that, high-end quartz sand also plays an important role in electronic information, optical fiber, photovoltaic and other industries, as well as in defense and military industry, aerospace and other fields. It can be said that small grains of sand support large industries.(Vertical ring high gradient magnetic separator）
At present, what kinds of quartz sand do you know?
01 Quartz sand of different specifications
Common specifications of quartz sand include: 0.5-1mm, 1-2mm, 2-4mm, 4-8mm, 8-16mm, 16-32mm, 10-20, 20-40, 40-80, 80-120, 100-200, 200 and 325.
The mesh number of quartz sand actually refers to the grain size or fineness of quartz sand. Generally, it refers to the screen within the area of 1 inch X 1 inch. The number of mesh holes that can pass through the screen is defined as the mesh number. The larger the mesh number of quartz sand, the finer the grain size of quartz sand. The smaller the mesh number, the larger the grain size of quartz sand.
02 Quartz sand of different quality
Generally speaking, quartz sand can be called quartz sand only if it contains at least 98.5% silicon dioxide, while the content below 98.5% is generally called silica.
The local standard of Anhui Province DB34/T1056-2009 “Quartz sand” is applicable to industrial quartz sand (excluding casting silica sand) made from quartz stone by grinding.
After years of development, at present, quartz sand is often divided into ordinary quartz sand, refined quartz sand, high-purity quartz sand, fused quartz sand and silica powder in industry.
Ordinary quartz sand
Generally, it is a water treatment filter material made of natural quartz ore after crushing, washing, drying and secondary screening; SiO2 ≥ 90-99%, Fe2O3 ≤ 0.06-0.02%. The filter material is characterized by no angle correction, high density, high mechanical strength, and long service life of pollutant carrying capacity line. It is a material for chemical water treatment. It can be used in metallurgy, graphite silicon carbide, glass and glass products, enamel, cast steel, caustic soda, chemical, jet noise and other industries.
Refined quartz sand
SiO2 ≥ 99-99.5%, Fe2O3 ≤ 0.005%, made of high-quality natural quartz sand, carefully selected and processed. Its main purpose is to produce acid-resistant concrete and mortar by making glass, refractory materials, smelting ferrosilicon, metallurgical flux, ceramics, abrasive materials, casting molding quartz sand, etc. Sometimes the refined quartz sand is also called acid washed quartz sand in the industry.
Glass sand
High-purity quartz sand is made of high-grade quartz stone through a series of processes. At present, the industry has not established a unified industrial standard for high-purity quartz sand, and its definition is not very clear, but generally speaking, high-purity quartz sand refers to quartz sand with SiO2 content of more than 99.95% or higher, Fe2O3 content of less than 0.0001%, and Al2O3 content of less than 0.01%. High-purity quartz sand is widely used in electric light sources, optical fiber communications, solar cells, semiconductor integrated circuits, precision optical instruments, medical utensils, aerospace and other high-tech industries.
Microsilica
Silicon micro-powder is a non-toxic, odorless and pollution-free silicon dioxide powder made from crystalline quartz, fused quartz and other raw materials through grinding, precision grading, impurity removal, high-temperature spheroidization and other processes. It is an inorganic non-metallic material with excellent properties such as high heat resistance, high insulation, low linear expansion coefficient and good thermal conductivity.
Fused quartz sand
Molten quartz sand is amorphous (glass state) of SiO2. It is a form of glass with permeability, and its atomic structure is long and disordered. It improves its temperature and low thermal expansion coefficient through cross linking of three-dimensional structure. The selected high-quality silica raw material SiO2>99% is fused in an electric arc furnace or resistance furnace at a melting temperature of 1695-1720 ℃. Due to the high viscosity of SiO2 melt, which is 10 to the 7th power Pa · s at 1900 ℃, it cannot be formed by casting. After cooling, the glass body is processed, magnetic separation, impurity removal and screening to produce granular fused quartz sand of different specifications and uses.
Fused quartz sand has the advantages of good thermal stability, high purity, stable chemical properties, uniform particle distribution, and thermal expansion rate close to 0. It can be used as filler in chemical industries such as coatings and coatings, and is also the main raw material for epoxy resin casting, electronic sealing materials, casting materials, refractory materials, ceramic glass and other industries.
03 Quartz sand for different purposes
Low iron sand for photovoltaic glass（magnetic drum magnetic separator）
Photovoltaic glass is generally used as the packaging panel of photovoltaic modules, which is in direct contact with the external environment. Its weatherability, strength, light transmittance and other indicators play a key role in the life and long-term power generation efficiency of photovoltaic modules. The iron ion in quartz sand is easy to dye. In order to ensure the high solar transmittance of the original glass, the iron content of photovoltaic glass is required to be lower than that of ordinary glass, and low-iron quartz sand with high silicon purity and low impurity content must be used.
High-purity quartz sand for photovoltaic
Solar photovoltaic power generation has become the preferred direction of solar energy utilization, and high-purity quartz sand has an important application in the photovoltaic industry. Quartz devices used in the photovoltaic industry include quartz ceramic crucibles for solar silicon ingots, as well as quartz boats, quartz furnace tubes and boat brackets used in the diffusion and oxidation of photovoltaic manufacturing process, and PECVD process. Among them, quartz crucibles are divided into square quartz crucibles for growing polycrystalline silicon and round quartz crucibles for growing monocrystalline silicon. They are the consumables during the growth of silicon ingots and are the quartz devices with the largest demand in the photovoltaic industry. The main raw material of quartz crucible is high-purity quartz sand.
Plate sand
Quartz stone has the properties of wear resistance, scratch resistance, heat resistance, corrosion resistance and durability. It has strong plasticity and is widely used. It is a benchmark product in the history of the development of artificial building materials. It has also gradually become a new favorite in the home decoration market and is popular with consumers. Generally, 95%~99% quartz sand or quartz powder is bonded and solidified by resin, pigment and other additives, so the quality of quartz sand or quartz powder determines the performance of artificial quartz stone plate to a certain extent.
The quartz sand powder used in the quartz plate industry is generally obtained from high-quality quartz vein and quartzite ore through crushing, screening, magnetic separation and other processes. The quality of raw materials directly affects the quality of quartz. Generally speaking, quartz used for quartz stone slab is divided into fine quartz sand powder (5-100 mesh, used as aggregate, the aggregate usually requires ≥ 98% silicon content) and coarse quartz sand (320-2500 mesh, used for filling and reinforcement). There are certain requirements for hardness, color, impurities, moisture, whiteness, etc.
Foundry sand
Because quartz has high fire resistance and hardness, and its excellent technological performance can meet various basic requirements of casting production, it can be used not only for traditional clay sand molding, but also for advanced molding and core making processes such as resin sand and coated sand, so quartz sand is widely used in casting production.
Water-washed sand: It is the raw sand for casting after natural silica sand is washed and graded.
Scrubbing sand: a kind of raw sand for casting. The natural silica sand has been scrubbed, washed, graded and dried, and the mud content is less than 0.5%.
Dry sand: the dry sand with lower water content and less impurities is produced by using clean deep groundwater as the water source, after three times of desliming and six times of scrubbing, and then drying at 300 ℃ – 450 ℃. It is mainly used to produce high-grade coated sand, as well as chemical, coating, grinding, electronics and other industries.
Coated sand: a layer of resin film is coated with phenolic resin on the surface of scrub sand.
Silica sand used for casting is 97.5%~99.6% (plus or minus 0.5%), Fe2O3<1%. The sand is smooth and clean, with silt content<0.2~0.3%, angular coefficient<1.35~1.47, and water content<6%.
Quartz sand for other purposes
Ceramic field: the quartz sand SiO2 used in the production of ceramics is more than 90%, Fe2O3 ∈ 0.06~0.02%, and the fire resistance reaches 1750 ℃. The particle size range is 1~0.005mm.
Refractory materials: SiO2 ≥ 97.5%, Al2O3 ∈ 0.7~0.3%, Fe2O3 ∈ 0.4~0.1%, H2O ≤ 0.5%, bulk density 1.9~2.1g/m3, liner bulk density 1.75~1.8g/m3, particle size 5.1~0.021mm.
Metallurgical field:
① Abrasive sand: the sand has good roundness, no edges and corners, the particle size is 0.8~1.5mm, SiO2 ＞ 98%, Al2O3 ＜ 0.72%, Fe2O3 ＜ 0.18%.
② Sand blasting: chemical industry often uses sand blasting to remove rust. SiO2 ＞ 99.6%, Al2O3 ＜ 0.18%, Fe2O3 ＜ 0.02%, particle size 50~70 mesh, spherical particle shape, Mohs hardness 7.
Abrasive field: The quality requirements of quartz sand used as abrasive are SiO2 ＞ 98%, Al2O3 ＜ 0.94%, Fe2O3 ＜ 0.24%, CaO ＜ 0.26%, and particle size of 0.5~0.8mm.
Post time: Feb-04-2023