Application fields and characteristics of mullite-based composites
Mullite is a binary solid solution compound composed of alumina and silicon oxide. It is the most stable compound in the Al2O3-SiO2 binary phase diagram. There are very few natural minerals. At present, aluminum-containing and silicon-containing raw materials are mostly synthesized at high temperature.
Mullite has many excellent physical properties, such as high fracture toughness, high temperature resistance, oxidation resistance, thermal shock resistance, creep resistance, low thermal conductivity, strong electrical insulation, and low dielectric coefficient. In addition, mullite also has high chemical stability, and has good corrosion resistance in alkaline fluxes and carbonated fluxes. Therefore, mullite can be used in a variety of composite materials, and has been widely researched and applied in the fields of chemical industry, energy, environment and so on.
1. Coating material
Because of its excellent stability and low thermal expansion coefficient, mullite is often used in coating materials to increase the thermal shock resistance and oxidation resistance of the material. Because mullite has good heat and corrosion resistance, the use of mullite in coatings can also enhance the high temperature corrosion resistance of the material.
2. Polymer materials
Adding mullite to polymer materials can significantly improve the properties of the materials. Feng et al. uniformly distributed acicular mullite whiskers into epoxy resin to prepare mullite whisker epoxy resin composite material, which can increase the flexural strength of epoxy resin from 4.2MPa to 47.6MPa, and the wear rate is also significant reduce. In addition, the addition of mullite can also improve the vulcanization characteristics and resilience of SBR.
3. Thermal storage materials
Phase change materials/ceramic matrix composite energy storage materials have become one of the important research directions of thermal energy storage materials. Mullite-based porous ceramic material is a good heat storage and energy storage matrix material due to its large heat capacity, good thermal shock resistance and high porosity.
Cordierite-mullite composite ceramics are one of the most promising thermal storage materials for next-generation solar thermal power systems. Wu et al. prepared a series of cordierite-mullite composite ceramic materials using different aluminum and silicon raw materials, which can be used as the matrix of thermal storage materials.
4. Wave-transmitting material
Mullite-based wave-transmitting ceramic materials have excellent thermal shock resistance, high-temperature mechanical properties, chemical stability and excellent mid-infrared wave-transmitting properties, and can be used as special high-temperature optical window materials, such as radomes and antenna windows for high-speed aircraft. Wait. Its wave transmittance is mainly affected by its microstructure, such as impurities, grain boundaries, pores, microcracks and surface roughness. The preparation process includes hot isostatic pressing, vacuum sintering, microwave sintering and spark plasma sintering.
Chromium-aluminum phosphate material is also an ideal wave-transmitting material, but its mechanical properties are poor, and its composite with mullite can improve its mechanical properties and thermal shock resistance. Zhou Pingsen et al. used multiphase composite ceramic technology to prepare mullite reinforced chromium aluminum phosphate high temperature wave-transmitting ceramics. The results show that with the increase of mullite content, the thermal shock resistance and mechanical properties of multiphase ceramics are improved. .
5. Thermal insulation materials
Mullite fiber-based porous material has the advantages of low density, low thermal conductivity and certain strength, and is an ideal thermal insulation material. Among them, mullite fiber mainly has two kinds of external introduction method and in situ synthesis method.
6. Ceramic membrane material
As a new type of separation medium, ceramic membrane has the advantages of high temperature and high pressure resistance, corrosion resistance, high separation efficiency, easy cleaning and regeneration, etc. It is widely used in environmental engineering, food, medicine, biotechnology and other separation processes. Due to its unique fibrous structure, mullite is often used to prepare ceramic separation membrane materials.
Electronic grade polysilicon: the "food" of the electronic information industry
With the vigorous development of the photovoltaic industry, the domestic polysilicon industry has reached the world's largest output in just over ten years, and the production cost has also reached the world's advanced level. High-purity polysilicon material is the basic raw material for the information industry and solar photovoltaic power generation industry, and many developed countries in the world regard it as a strategic material.
The purity requirements of electronic grade polysilicon are extremely high, and it is the purest substance that can be obtained by human industrialization.
Electronic grade polysilicon can be divided into electronic grade polysilicon for zone melting and electronic grade Czochralski polysilicon. The quality requirements of polysilicon for electronic grade zone melting are more stringent. The monocrystalline silicon produced by the zone melting method has low oxygen and carbon content, low carrier concentration and high resistivity. It is mainly used in the manufacture of IGBTs, high-voltage rectifiers, thyristors, and high-voltage transistors. and other high-voltage and high-power semiconductor devices. The monocrystalline silicon wafers produced by the Czochralski method are widely used in integrated circuit memories, microprocessors, mobile phone chips, low-voltage transistors, electronic devices and other electronic products. %above.
In addition, my country's electronic-grade polysilicon testing equipment still relies on imports. On the manufacturing side, my country has basically solved the localized substitution of related equipment and materials. However, the core testing equipment for polysilicon products is completely dependent on imports, such as low-temperature Fourier transform infrared spectrometer LT-FTIR, inductively coupled plasma mass spectrometer ICP-MS, etc., and the testing process requires extremely high levels of testing personnel.
Judging from the current international development of electronic-grade polysilicon production technology, the production processes mainly include silane method, gas-liquid deposition method, fluidized bed, and improved Siemens.
The production cost of silane method is high, and the silane used is explosive, flammable, and has poor safety. Even at room temperature, there will be a fire hazard. The gas-liquid deposition method was developed and controlled by Japan. In production, a tubular reactor is mainly used, and the operating temperature condition is controlled at 1500 °C to generate liquid silicon directly in the gas. Currently, it is still in the research and test stage. Not used for mass production. The fluidized bed process method is mainly to carry out comprehensive control of product impurities, so it cannot produce high-quality electronic-grade polysilicon.
Electronic grade polysilicon is the most basic strategic material in the electronic information industry, which is related to my country's national economy, society and national defense security. How to continuously and stably produce high-purity electronic-grade polysilicon to meet the needs of downstream enterprises for electronic-grade silicon materials is an important research topic faced by polysilicon enterprises. It is necessary to strictly control all processes in the whole process of polysilicon production, reduce various factors that may cause pollution to a minimum, and further implement lean and refined operations in the operation process, change bad habits, and improve management. Electronic grade polysilicon has a place in the market.
The formula for surface modification is actually not simple!
1. Why should powder surface modification be carried out?
Surface modification can make inorganic powder change from general filler to functional modifier, and the purpose of modification is to select the necessary premise of modification method:
In order to enhance the compatibility between inorganic powder and organic polymer and the dispersibility in organic matter, to improve the mechanical strength and comprehensive performance of the material, organic surface modification can be selected;
To obtain new mineral intercalation compounds, such as clay or graphite intercalation compounds, intercalation modification can be selected;
In order to replace silica and supplement the deficiencies of silica in some properties, the surface can be coated with silica;
To replace titanium dioxide or reduce the amount of titanium dioxide, the surface can be coated with titanium dioxide;
In order to improve some special properties of rubber products, metal particles can be selected on the surface;
In order to improve the optical efficiency and visual effect of the product, metal oxides such as titanium oxide, chromium oxide and iron oxide can be selected on the surface.
2. How to choose a surface modifier?
The selection of surface modifier is the key to achieve the expected purpose of powder surface modification, and it has strong pertinence.
From the point of view of the interaction between the surface modifier molecules and the surface of the inorganic powder, the surface modifier that can chemically react or chemically adsorb with the surface of the powder particles should be selected as much as possible, because the physical adsorption is strong in the subsequent application process. Easy to desorb under stirring or squeezing, for example:
Inorganic powders (fillers or pigments) used for various plastics, rubbers, adhesives, oil-based or solvent-based coatings require good surface lipophilicity, that is, good affinity or compatibility with organic polymer binders, which It is required to select a surface modifier that can make the surface of inorganic powder hydrophobic and lipophilic;
The surface functional groups and reactive sites of calcined kaolin are mainly Si-O and Al-O bonds, so surface modifiers that are easy to form chemical coordination with Si-O and Al-O bonds should be selected;
For acidic minerals such as quartz powder, clay, wollastonite, and diaspore that contain more silicic acid, it is better to use silane coupling agent.
Titanate and aluminate coupling agents have chemical adsorption with basic minerals such as calcium carbonate under certain conditions and to a certain extent.
3. How to choose the surface modification process?
The surface modification process must meet the application requirements or application conditions of the surface modifier, have good dispersibility of the surface modifier, and can achieve uniform and firm coating of the surface modifier on the surface of the powder; at the same time, it requires a simple process and parameters. Good controllability, stable product quality, low energy consumption and low pollution.
Therefore, when selecting a surface modification process, at least the following factors should be considered:
Characteristics of the surface modifier, such as water solubility, hydrolyzability, boiling point or decomposition temperature;
Whether the front-end pulverization or powder preparation is wet or dry;
Modified process conditions, such as reaction temperature and reaction time.
4. How to choose surface modification equipment?
There are many types of powder surface modification equipment, including dry modification equipment and wet modification equipment. The selection is based on the surface modification method and process. The selection principles are as follows:
Good dispersibility for powders and surface modifiers. Only with good dispersibility can the powder and the surface modifier have a more equal opportunity and effect, and the amount of the surface modifier can be reduced.
The modification temperature and residence time can be adjusted within a certain range.
Low energy consumption and low wear per unit product. In addition to modifiers, the main cost of surface modification is energy consumption. Modification equipment with low energy consumption can reduce production costs and improve product competitiveness; low abrasion can not only avoid the pollution of modified materials, but also improve the operation of equipment. efficiency and lower operating costs.
In short, the purpose, method, process, equipment and other aspects of surface modification affect each other. It is necessary to consider comprehensively, take into account both left and right, and continue to explore in the correct thinking and direction, in order to find the most suitable surface modification technology for oneself.
Influence of talc purity on plastic modification effect
Plastic reinforcement modification is an important application field of talc, especially for polypropylene modification in the automotive and home appliance industries. Talc can increase the heat distortion temperature of products, increase dimensional stability, and reduce molding shrinkage. Ultrafine talc improves the rigidity, creep resistance, and impact strength of products. Therefore, many of the interior parts, exterior parts and structural parts of vehicles use talc-reinforced modified polypropylene materials.
Purity refers to the talc content of the product. The higher the purity of talc, the better its reinforcing effect. The direct measurement of talc purity is more complicated and can be estimated by the loss on ignition at 1050 °C, which is generally expressed by SiO2. The lower the loss on ignition, the higher the SiO2 value and the higher the purity. The SiO2 content of pure talc is 63.47%, and the loss on ignition is 4.75%. The enhancement and modification effect of talc powder with loss on ignition <8.5% is obvious; the enhancement effect of modification with loss on ignition is 8.5% to 16% is weak;
Natural talc contains impurity minerals, which will have various adverse effects on the modification effect. These impurities include: magnesite, dolomite, chlorite, quartz, iron salts, heavy metals, etc.
Studies have shown that the types and contents of talc impurities in different origins are different, and their effects on reinforcement and modification are also different. Magnesite and dolomite have obvious adverse effects on flexural modulus and thermal stability, and chlorite also has The adverse effects are smaller than those of magnesite and dolomite; heavy metals and iron salts have adverse effects on the anti-aging and thermal stability of plastics; the effects of heavy metals need to be treated differently, and the heavy metals in the talc structure are higher than those in carbon. Heavy metals in acid salts and other impurity mineral structures have less effect.
Therefore, when choosing a type of talc, not only should pay attention to its purity, but also understand the source of origin and the type and content of impurities in it.
5G commercial upgrade, CCL functional fillers usher in new opportunities
As the main material for processing and manufacturing printed circuit boards (PCBs), CCL can be used in the production of high-speed transmission equipment such as servers and memories, as well as components such as antennas, power amplifiers, and radars. It is widely used in televisions, radios, computers, computers, Mobile communications and other electronic products.
In 5G base stations, the circuit boards processed and manufactured by CCL are mainly used to produce communication equipment such as communication base station antennas and power amplifiers, which are installed in the communication network. Due to the substantial increase in communication frequency and transmission rate brought about by the upgrade of 5G communication technology, traditional CCL cannot meet the production requirements, and high-frequency and high-speed CCL has become the current main development trend of CCL.
According to the data, functional fillers are the main bearers of mechanical strength in substrate composites, so they are usually regarded as one of the most important research directions in the upgrading of copper clad laminate technology. The rapidly expanding and upgrading market also puts forward higher requirements for the supply of upstream materials in related industries. The domestic high-frequency and high-speed circuit board packing and mobile phone HDI board packing industries are expected to benefit from this industrial upgrading wave and achieve rapid development.
In order to meet the needs of high-frequency and high-speed data transmission, high-performance circuit substrates have become a necessary choice for making high-frequency and high-speed copper clad laminates. At present, with excellent dielectric constant and low dielectric loss performance, silica material is filled in polytetrafluoroethylene (PTFE) substrate as a reinforcing material, which has become the most important technical route for high-frequency and high-speed copper clad laminates. After adding silica functional filler, the dielectric properties and signal transmission quality of high-frequency and high-speed copper clad laminates can be improved to meet the quality requirements of 5G communication. At the same time, the silica functional filler also effectively improves the heat resistance and reliability of the circuit board.
In the current global high-end silica functional filler market, Japanese and American manufacturers still occupy a major position. However, with the further upgrading of my country's 5G market, the copper clad laminate industry will gradually concentrate in China, and my country has also achieved large-scale production of spherical silicon micropowder, gradually forming a domestic alternative.
The high-end electronics industry is developing rapidly, and the market demand for spherical silica powder is large
Spherical silica powder is made of selected angular silica powder as raw material and processed into spherical silica powder material by flame method. It has good fluidity, low stress, small specific surface area and high bulk density. It can be obtained as a filler. Higher filling rate and uniformity are widely used in high-end PCB boards, epoxy molding compounds for large-scale integrated circuits, high-end coatings, special ceramics, etc. The price is 3-5 times that of angular silicon powder.
Silicon micropowder is one of the core basic raw materials of the electronics industry, and the expansion of the advanced packaging market has driven the growth of the demand for spherical powder. According to Yole data, with the upgrading of the electronics industry, the scale of the advanced packaging market has gradually expanded. It is expected to occupy nearly 50% of the packaging market share in 2024, which is expected to further drive the growth of spherical silicon micropowder demand.
With the vigorous development of high-end electronic industries such as 5G intelligence, high-performance copper clad laminates and chip packaging industries are expected to drive the incremental market for silicon micropowder fillers. According to Absolute reports, the global sales of spherical silica for fillers will reach 159,000 tons in 2023, and its market size will reach US$660 million in 2024, with CARG5 reaching 9.2%. The output of spherical silica in the same year is estimated to be 184,900 tons, and the overall production and sales continued to grow. According to the data of the global copper clad laminate and chip packaging industry calculated by Guotai Junan Securities Research Institute, the total global demand for spherical silicon micropowder is expected to increase from 225,800 tons in 2020 to 396,200 tons in 2025, with an average compound growth rate of 11.90 tons from 2020 to 2025. %.
There is a broad prospect for automobile intelligence. The demand for printed circuit boards (PCB) for a single new energy vehicle is more than 5 times that of ordinary vehicles. According to industry chain research and other data, it is estimated that the demand for spherical silicon powder for new energy vehicles will reach 28,231.6 tons, of which the new energy vehicle copper clad laminate and the spherical silicon micro-powder for chip packaging increased to 15,880.3/12,351.3 tons respectively.
The general trend of the Metaverse is driving the development and upgrading of computing power. On the one hand, the growth of servers has expanded the demand for PCBs; on the other hand, high-speed, large-capacity, and high-performance servers will continue to develop, creating a large demand for high-level, high-density, and high-speed PCB products. According to industry chain research and other data, it is estimated that the demand for spherical silicon powder for servers will reach 18,542.1 tons in 2025, of which the filling volume of spherical silicon powder for copper clad laminates and chip packaging will increase to 10,429.9/8,112.2 tons in 2025, respectively.
The demand for high-performance PCB drives the expansion of the spherical microsilica market. The short-wave and high-frequency characteristics of 5G communication technology have higher requirements on the transmission speed, transmission loss, heat dissipation and other performance of the PCB, and the investment in routers, switches, IDCs and other equipment required to carry larger bandwidth traffic has increased accordingly. High-frequency and high-speed copper clad laminates need to use low-dielectric, low-loss fused silicon micropowder and spherical silicon micropowder as key functional fillers, and require low powder impurity content and high filling rate. Therefore, the demand for high-performance spherical silicon micropowder is gradually expanding. According to industry chain research and other data, it is expected that the total filling volume of spherical silicon micropowder for 5G base stations will increase to 1,295.8 tons in 2022.
Main application fields and characteristics of inorganic salt whiskers
Due to their high aspect ratio, high strength and tensile properties, inorganic salt whiskers can often be used as an important reinforcing material to be added to flame retardant materials, building materials, composite materials and friction materials. The action mechanism of whiskers in composites is mainly reflected in four aspects: load transfer, crack bridging, crack deflection and pull-out effect. Due to the high strength and high modulus of inorganic salt whiskers, when added to the composite material, it can play a certain role in strengthening and toughening the composite material.
1. Flame retardant materials
Research on the fire performance of new building materials is an important part of public protection and a necessary condition for large-scale application in construction projects. Due to its excellent high temperature resistance, inorganic salt whiskers are often added to other materials as flame retardant materials to improve the flame retardant properties of composite materials.
2. Building materials
At present, in the material consumption industry, the construction industry is one of the largest material consumption industries, accounting for about 24% of the global material consumption. In building materials, inorganic whiskers are widely used in building materials due to their certain aspect ratio and their excellent physical and chemical properties. Inorganic whiskers have crack resistance and filling effects at the microscale, so doping the whiskers into the composite material can effectively improve the comprehensive performance of the composite material.
3. Composite materials
Inorganic whiskers, as fillers, can enhance the physical and mechanical properties of composites to a certain extent. At the same time, the study pointed out that proper modification of whiskers can improve the comprehensive properties of composites.
4. Friction material
In recent years, whiskers as functional fillers have a certain enhancement effect on the improvement of automobile braking friction performance. RAJ et al. explored the effect of calcium sulfate whiskers as functional fillers on the friction performance of automobile brakes. By changing the content of calcium sulfate whiskers, according to the JASOC406 standard, a tribological study was carried out on an inertial brake dynamometer. The results showed that the mechanical properties of the material with the addition of 10% calcium sulfate whiskers were improved, and the friction was improved at the same time. performance, friction materials containing calcium sulfate whiskers wear less.
Commonly used modification equipment and characteristics of traditional Chinese medicine powder
The research on traditional Chinese medicine powder modification equipment started late, and the development is relatively lagging behind, mainly from the chemical industry, plastics, crushing, dispersion and other industries for reference. At present, the equipment used for traditional Chinese medicine powder modification mainly includes spray dryer, fluidized bed, ball mill, vibration mill, high-speed stirring mixer, airflow impact coating machine, continuous surface modification machine, Comil grinding and granulating machine, etc.
Among them, spray dryer, fluidized bed, ball mill and vibration mill are widely used in the field of traditional Chinese medicine powder modification. High-speed mixing mixer, air impact coating machine, continuous surface modification machine, Comil pulverizing and granulating machine, etc. have their own specific advantages in powder modification.
1. High-speed mixing mixer
When the high-speed mixing mixer is working, the material moves tangentially along the impeller with the help of the friction between the surface of the high-speed rotating blade and the material and the thrust of the side to the material. Due to the action of centrifugal force and gravity, the material is thrown to the inner wall of the mixing chamber. And it rises along the wall to a certain height and then falls back to the center of the impeller. This reciprocation causes the material to continuously move up and down in a spiral shape in the mixing chamber. The surface temperature of the material increases correspondingly, which promotes sufficient cross-mixing and adsorption between the drug powder particles and the modifier, so that the surface modifier coats the surface of the drug particles to achieve the purpose of powder surface modification.
2. Air impact cladding machine
There are many series of air impact cladding machines, and now the HYB system is taken as an example. The HYB system was developed by Tokyo University of Science and Nara Machinery in 1986. The main engine consists of a high-speed rotating rotor, stator and circulation loop.
3. Continuous Surface Modifier
When working, the material and modifier pass through the three mixing chambers in turn from the feeding port. The high-speed rotation of the rotor in the mixing chamber is forced to loosen the material and form a vortex two-phase flow. At the same time, the material passes through the impact and shear of the rotor and stator in the mixing chamber The energy required for surface modification is generated by the friction effect, so that the surface modifier can quickly interact with the surface of the drug powder particles to realize the powder coating modification effect.
4. Comil crushing and granulating machine
In recent years, some progress has been made in the application of Comil pulverizer and granulator to surface modification of chemical powder to improve the fluidity of chemical powder. Yu Yanhong et al. applied Comil pulverizer to improve the surface modification of traditional Chinese medicine extract powder The fluidity of traditional Chinese medicine extract powder has also achieved certain results.
3 Major Degradable Plastic Modification Technologies
At present, the price of degradable plastic resin is relatively high, and most of the degradable plastic products are ordinary daily necessities, which will seriously hinder the large-scale promotion and application of degradable plastic products. The development of cheap degradable plastic products is one of the core contents of the application of degradable plastics. Therefore, starch, calcium carbonate, talc, etc., which do not affect the degradation performance of products and can be absorbed by the environment, are used in the modification system of degradable plastics. In particular, the high proportion of filling technology has become one of the important technologies in the development of degradable plastic products.
Common modification techniques in the application process of degradable plastics include filling modification, alloying modification and copolymerization modification.
1. Filling modification
Filling modification is to add non-melting powder additives to the degradable plastic resin, mainly including starch and inorganic powder. Its main purpose is to prepare cheap special materials, and sometimes it can also improve the mechanical properties such as the strength of special materials.
A commonly used filler aid is starch. It is a common natural degradable polymer with a wide range of sources and low price. The degradation products are carbon dioxide and water, which do not pollute the environment, and it is a renewable biomass resource. The most important thing to pay attention to in this filling technology is the treatment of starch, because the compatibility of starch and degraded plastics is poor, and it is necessary to plasticize the starch so that the starch can be better combined with the plastic matrix.
Another filling aid is inorganic powders such as calcium carbonate and talc. They are all natural mineral powders, which can be absorbed by nature after returning to nature, so they will not affect the degradation performance of the entire degradable plastic system, but can effectively reduce the cost of modified materials and improve the strength of materials to a certain extent. Therefore, it is very common to use calcium carbonate and other fillers in products that do not require high mechanical properties. The filling technology should pay attention to the coupling treatment of the powder surface, which will directly affect the product performance and the amount of inorganic powder that can be added.
2. Alloying modification
Alloying modification is one of the most important technologies in the application of degradable plastic modification. Alloying material refers to a special material composed of two or more different varieties of degradable plastics by melt blending and compounding, generally containing one continuous component and other dispersed components. Some properties of the material show continuous phase properties and some properties show dispersed phase properties. Therefore, new special materials can be obtained that concentrate the advantages of several degradable plastics, which can meet the needs of more products.
3. Copolymerization modification
Copolymerization modification refers to the introduction of other structural units on the molecular chain of the polymer to change the chemical structure of the polymer and realize the modification of the material. For example, PLA is a hydrophobic polymer, which limits its application in some fields (such as drug carriers). An effective method is to use lactide to copolymerize with hydrophilic polymers (such as polyethylene glycol, polyglycolic acid, polyethylene oxide) to introduce hydrophilic groups or blocks into the PLA molecule. For example, the PLA-PEG-PLA sustained-release material is prepared by ring-opening polymerization of polyethylene glycol and lactide, which improves the hydrophilicity and degradation rate of the PLA material, and the prepared PLA-PEG-PLA can become a sustained-release material. Material of drug-loaded microspheres.
PHBV has many excellent properties such as biocompatibility and optical activity, and is widely used, but its products are hard and brittle and difficult to process. The graft modification method can be used to introduce the polar functional group polyvinylpyrrolidone (PVP) on the main chain of PHBV to synthesize the graft copolymer PHBV-g-PVP of PHBV and PVP. The crystallization rate and crystallinity of the copolymer decreased, the hydrophilicity of the membrane increased, and the sustained drug release rate increased.
7 Types And Uses Of Quartz Mines
Natural quartz deposits have various origins. 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 transparent large quartz crystal mineral, the main component is silicon dioxide. Crystals are mostly formed by natural growth in caves, rock cracks or joints, and faults. Their growth conditions are relatively harsh, and four conditions must be met at the same time: ample growth space, capable of providing silica-rich hydrothermal fluid, and a certain temperature. and stress, enough time to grow.
Natural crystal deposits have small reserves, poor mining conditions, scarce resources, and high prices, making it difficult to meet the needs of large-scale industrial production. However, due to the rich colors of natural crystal, 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 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.
Quartz sandstone deposits are generally large in scale, with stable geological occurrence and good mining conditions. At the same time, the ore hardness is generally relatively low, the natural particle size is moderate, and it is easy to be broken, classified and produced in large-scale industrial production. However, due to the complex composition of quartz sandstone cement, it is usually used in the production of daily glass sand, glass fiber, metal silicon, refractory materials, white carbon black, organic silicon and other fields.
3. Quartzite
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, the associated minerals often contain trace amounts of tourmaline and hematite. and zircon etc. Compared with quartz sandstone, the ore of quartzite is more dense and hard.
4. Pulse Quartz
It is mainly formed under the action of magmatic hydrothermal fluid, usually in the form of a dense block structure. 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, steep in appearance, generally several meters to tens of meters in thickness, and generally ten to several hundred meters in length. A mining area can be composed of one vein or multiple veins.
The resource reserves of vein quartz deposits are generally relatively small, and the mining difficulty is relatively high. However, due to its low impurity content and stable resource quality, it is mostly used for the preparation of SiO2 99% to 99.9% silicon micropowder and low-iron quartz. Sand, optical glass, semiconductor and other high-quality quartz products.
5. Pink Quartz
Sedimentary weathered deposits are usually formed by weathering and disintegration of siliceous parent rocks under special geological structural conditions (temperature and humidity paleoclimate, gentle topography, paleogeography, hydraulic action, etc.). The quartz content is usually 95%~98%. can be as high as 99% or more.
6. Natural quartz sand
Natural quartz sand is a kind of sandy quartz mineral raw material with quartz as the main mineral component, which is 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 amphibole are mainly marine sedimentary placer deposits and river-lake sedimentary placer deposits.
7. Granite
Refers to the quartz in large-grained granite or granite pegmatite (white granite) formed by the consolidation of magma. The quartz grade 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, which is currently mainly produced in Spruce Pine, North Carolina, USA.