Application of Inorganic Filler in Coating Industry and Market Status
As an important material, coatings are widely used in construction and industrial fields. According to the application field, it can be divided into architectural coatings, industrial coatings, general coatings and auxiliary materials.
Architectural coatings: wall coatings, waterproof coatings, floor coatings, functional architectural coatings, etc.;
Industrial coatings: automotive coatings, wood coatings, light industrial coatings, marine coatings, anti-corrosion coatings, etc.;
General and auxiliary materials: blending paint, varnish, enamel, primer, putty, auxiliary materials (thinner, moisture-proof agent, drier, curing agent, etc.).
As the most used powder material in coatings, pigment fillers play an important role in improving, enhancing, and innovating the performance of coatings (coating films). Pigments for coatings include carbon black, iron oxide, titanium dioxide, etc., and fillers are also called inert pigments, volume pigments, and brighteners, which refer to white and colorless pigments that do not have tinting power and hiding power. According to different mineralogical characteristics and basic chemical composition, fillers can be roughly divided into carbonate, silicate, silica, barium sulfate and aluminum hydroxide.
- The role of inorganic fillers in coatings
Cost reduction: The thickness of the coating film can be increased by filling, which acts as a skeleton in the coating, making the coating film plump and thick, and therefore can reduce the cost of coating production.
Incremental enhancement: The filler can adjust the rheological properties of the coating, such as thickening, anti-settling, etc., and can also improve the mechanical strength of the coating film, such as improving abrasion resistance and durability.
Improve performance: The chemical composition, light, heat, electricity, magnetism and other properties of inorganic fillers can give coatings some functions.
- Selection index of inorganic filler
There are many types and specifications of fillers, and the use of high-quality and stable products is very important to ensure the performance of the coating. In the selection of fillers, in addition to paying attention to its chemical composition and mineral form, the filler's particle size and distribution, hardness, oil absorption value, aspect ratio and other characteristics are also indicators that must be considered.
Application of Inorganic Filler in Coating Industry
- Calcium carbonate
Basic performance: the most versatile extender pigment; chemically active, reducing film blistering, anti-mildew, and flame retardant; it not only reduces the cost but also acts as a skeleton, can increase the thickness of the film, improve the mechanical strength, abrasion resistance, and suspension.
High-quality natural calcium carbonate products are made of calcite, with high whiteness, and can be made into powders of various meshes required for coatings. Synthetic calcium carbonate is also called light calcium carbonate or precipitated calcium carbonate. Because the particles are finer, the oil absorption is greatly increased, and it is slightly alkaline. Synthetic calcium carbonate should not be used with pigments with poor alkali resistance. It can be used as a filler for water-based interior wall coatings in architectural coatings, but due to weather resistance and color retention It has poor performance and is rarely used in exterior wall coatings.
- Dolomite
Basic performance: The theoretical composition is w(CaO)=30.4%, w(MgO)=21.7%, w(CO2)=47.9%, often containing impurities such as Fe, Si and Mn. It has the characteristics of surface adsorption, can provide magnesium and calcium source, high refractoriness, large specific surface area, good heat insulation and heat preservation effect.
Dolomite powder can be used as a pigment filler in the coating industry to improve the weather resistance, rarity and scrub resistance of coatings. Mainly used in industrial protective coatings and marine coatings.
- Kaolin
Basic performance: The chemical composition is hydrated aluminum silicate, which has the properties of white color, low cost, good fluidity and suspension, chemical inertness, strong covering power, etc.; outstanding light resistance, acid, alkali and salt resistance, and good anti-settling effect.
Kaolin can increase the hiding power of titanium dioxide or other white pigments, and improve the rheology and gloss of coatings. In the paint, it mainly plays the role of filler and pigment substitute, and can reduce the demand for anggu dyes. Kaolin can also increase the hardness of the coating film, improve the quality of the coating film, and make the coating have good anti-corrosion, opacity and anti-settling properties. It can be widely used in water-based or solvent-based flat paint, semi-gloss paint, eggshell paint and special paint.
- Barium sulfate
Basic performance: There are usually two existing forms, namely natural barite powder and precipitated barium sulfate. Barium sulfate is an inert substance with high chemical stability, increased density, acid and alkali resistance, light resistance and heat resistance.
Barite powder is mainly used in primers in the coating industry. With its low oil absorption and low paint consumption, it can be made into thick film primers. And it has good filling, leveling and permeability resistance, which can increase the hardness and abrasion resistance of the coating film. Generally speaking, the performance of precipitated barium sulfate is better than that of natural products. It has high whiteness, fine texture and anti-blooming. The disadvantage is that it is dense and easy to precipitate.
- Wollastonite
Basic performance: The chemical composition is calcium metasilicate, and its length is 13 to 15 times the diameter. It has the characteristics of enhanced filling, chemical stability, good thermal stability and dimensional stability, excellent electrical properties, and high whiteness and brightness.
Wollastonite can increase the bright tone of white paint, and can replace white powder and titanium dioxide without reducing the whiteness and hiding power of the paint. Wollastonite can also improve the leveling of coatings and can also be used as a good suspending agent for coatings. Wollastonite used in primers can provide anti-corrosion performance, and can improve scratch resistance and crack resistance.
- Mica powder
Basic performance: Mica powder exists in nature in the form of multi-layer crystalline flakes. It has good transparency and high refractive index, high insulation strength and large electrical resistance, and excellent corona resistance and Mechanical properties and acid and alkali resistance.
Mica powder can impart flexibility, water resistance, weather resistance, chemical resistance, heat resistance and electrical insulation to the coating film. The horizontal arrangement in the paint can prevent ultraviolet radiation and protect the coating film, and can also prevent moisture from penetrating. In architectural coatings, the introduction of mica powder can improve the crack resistance of the coating film and improve the scrubbing resistance. A small amount of mica is used as a special component of steel structure primer, which can improve salt spray resistance and durability.
- Talcum powder
Basic performance: Talc powder is a magnesium silicate mineral. The layered basic unit structure is stacked on each other through extremely weak van der Waals force, and the layers are easily separated, giving it a certain degree of softness. It has good electrical insulation, heat resistance, chemical stability, lubricity, oil absorption, hiding power and mechanical processing properties.
In the field of industrial coatings, especially in primers, the introduction of talc powder can improve the corrosion resistance and crack resistance of the coating film, and can improve the adhesion and sanding properties, and can also play a role in preventing settling and sagging.
- Feldspar powder
It is a typical frame-like structure of mineral filler. According to different cations, feldspar powder mainly exists in three forms of albite, potash feldspar and anorthite. The morphology of feldspar powder is composed of nodular particles with edges and corners. Compared with spherical or ordinary block fillers, it can form a denser coating film, impart high wear resistance and scratch resistance to the coating film, and improve the coating film performance. Anti-corrosion performance.
- Silica
It can be divided into two categories: natural and artificial.
Natural products include crystalline silica, that is, quartz sand, which is mainly used in the preparation of architectural real stone paint.
There is also amorphous natural silicon dioxide, namely diatomaceous earth. Due to its low density and porosity, it is commonly used in interior wall coatings to absorb and eliminate odors. In addition, diatomaceous earth has an ionic effect, which can decompose water molecules into positive and negative ions, thereby generating strong oxidation and having a certain sterilization effect.
Artificial products include precipitated silica and synthetic fumed silica.
Precipitated silica uniformly dispersed in the coating film can produce a micro-rough surface, which makes the light diffusely reflected and has a strong matting effect.
Synthetic fumed silica, also known as white carbon black, has a thickening effect and exhibits certain thixotropy in coatings. In the water-based acrylic system, the introduction of silica may reduce the aging resistance of the coating film. This is because the metal ion impurities contained in silica will cause the coating film to undergo photo-oxidative degradation under ultraviolet light irradiation, and the silanol groups in the silica channels will also promote the photodegradation reaction.
- Bentonite
Basic properties: The special layered structure gives bentonite special properties, such as water absorption, swelling, thixotropy, rheology, etc.
Bentonite is mainly used as an auxiliary agent in coatings, such as thickeners, anti-settling agents, dispersants, etc., to prevent the sedimentation of pigments and fillers in the coatings.
According to the type of bentonite, calcium-based bentonite and sodium-based bentonite are mainly used in water-based coatings, while organic bentonite is mainly used in solvent-based coatings, and lithium-based bentonite can be used in water-based coatings.
- Aluminum hydroxide
As a flame-retardant filler, aluminum hydroxide has good thermal stability and has the three major functions of flame-retardant, smoke suppression and filling. It is the most important inorganic filler in fire-retardant coatings. The flame-retardant principle is that aluminum hydroxide releases water at high temperatures, an endothermic reaction occurs, and the water evaporates and consumes additional energy. After the aluminum hydroxide is decomposed, a barrier layer is formed, which can slow down the flow of oxygen and the rate of generation of other gases. The resulting aluminum oxide residue is deposited on the surface to isolate the oxygen and achieve the effect of inhibiting combustion. In addition, aluminum hydroxide's low absorption of ultraviolet light makes it very suitable for UV curing coating systems.
Market overview of the coating industry
The increase in demand in the coatings market is mainly due to the growth of investment in the construction industry, the development of the automobile industry, the increase in urban population and the improvement of the global economy. According to data from the World Paint and Coatings Industry Association (WPCIA), with the exception of 2015, the global coatings market showed a growth trend from 2012 to 2019. In 2019, the global coatings market was worth 172.8 billion U.S. dollars, an increase of 4.8% compared to 2018.
Competition in the global coatings market is fierce. Due to the large number of coating categories and the large differences in downstream demand in the industry, there are a large number of companies and the industry is relatively fragmented. From a regional perspective, Asia Pacific, Europe and North America are the leading regions in the global coatings industry. The Asia-Pacific region is the world's largest coatings market. The Asia-Pacific region accounted for 57% of sales in 2019, an increase of 7pct compared to 2018.
Article source: China Powder Network
The development trend of superfine grinding equipment
Ultrafine pulverization technology is a new pulverization technology developed to meet the requirements of modern technology. It can process raw materials into micron or even nanometer-sized powder. It has been used in chemicals, food, pesticides, cosmetics, dyes, coatings, electronics, aviation It is widely used in many fields such as aerospace.
With the continuous increase of social demand, ultra-fine grinding equipment is facing great challenges in terms of performance, finished product quality, service life and other issues. Therefore, equipment manufacturers are increasing their own research and development efforts, and constantly improving equipment in the ultra-fine grinding The adjustment and control technology of crushing force, particle size distribution, grain shape and crystal shape at work, in order to achieve more efficient production.
This requires all machinery manufacturers to make targeted improvements to the environmental protection and low-consumption performance of ultra-fine powder processing and production equipment, and strive to achieve low energy consumption, high output, no pollution, and good particle size of finished materials in ultra-fine grinding technology. Unique performance advantages such as good dispersibility can improve the competitiveness and market share of ultra-fine grinding equipment.
Modern production not only pursues production efficiency and finished product quality, but also develops in the direction of environmental protection and energy saving. The same is true in the pharmaceutical machinery industry. Looking at the requirements of modern social productivity, the overall development trend of material ultrafine grinding technology is the reverse development of low cost, high efficiency, strong controllability, good dispersion, and stable quality. Various types of ultrafine grinding equipment put forward higher technical requirements.
Modern engineering technology will require more and more high-purity ultra-fine powder, and ultra-fine powder technology will play an increasingly important role in high-tech research and development. High-purity ultra-fine powder is prepared by chemical synthesis, but the cost is too high and it is extremely difficult to use in industrial production. The main method of obtaining ultra-fine powder is still mechanical pulverization. Ultra-fine pulverization technology is a synthesis of various technologies, and its development also depends on the progress of related technologies. Therefore, the main development trends of ultrafine grinding equipment are as follows:
(1) Develop fine grading equipment matched with ultra-fine grinding equipment.
(2) Develop ultra-fine grinding equipment with low energy consumption, small footprint and large processing capacity.
(3) Integrated development of equipment and process research. Superfine grinding and supporting equipment must adapt to specific material characteristics and product indicators, and scale models must adapt to a large range.
Principles and advantages of activated carbon ultrafine pulverizer
Activated carbon material has stable chemical properties, high mechanical strength, acid resistance, alkali resistance, heat resistance, insoluble in water and organic solvents, and can be recycled. It has been widely used in chemical engineering, environmental protection, food processing, metallurgy, drug refining, military chemical protection And so on in various fields. At present, modified activated carbon materials are widely used in sewage treatment, air pollution control and other fields, showing bright prospects in the treatment of environmental pollution. Activated carbon can exert its value to a greater extent after being superfinely pulverized.
Activated carbon has the characteristics of developed pore structure, large specific surface area and smooth surface, so ordinary powder crushing equipment is not suitable for crushing activated carbon. In view of the high production cost and low production efficiency of activated carbon, the ultra-fine pulverizer uses hammers, blades, rods, etc. on the high-speed rotating body to impact the crushed materials, and uses the fierce impact of the material and the rotating body to fly at high speed. The high-speed impact between the materials and the shearing and grinding of the rotating body and the stator or the side wall realize the purpose of ultra-fine crushing of the materials.
The unique crushing mechanism determines its wide range of applications, powerful functions and changeable characteristics: it can be applied to plant fiber materials, plant shell materials, and non-mineral light calcium, heavy calcium crushing, etc. . Compared with the traditional coarse crusher, its fineness can be crushed to finer: the finest can reach 1500 mesh (8 microns); the single processing capacity is larger: the current maximum processing capacity is 8 tons per hour at 1000 mesh.
After the reorganization of the main machine structure and the adjustment of the rear supporting components, this machine can be made into a high-efficiency dispersing machine. Its dispersing efficiency is high: a single unit has a large processing capacity; a high dispersing fineness: it has been applied to nano-active carbonic acid. Dispersion of calcium; wide range of applications: when the hardness of the material is moderate, it can be used to disperse the material under conditions such as compaction after drying, agglomeration after long-term storage, and long-term dampness. During the break up operation, this machine also has the advantages of maintaining the original crystal grain shape and protecting the surface film of the powder.
The complete set of equipment comes standard with an impact mill host, a vertical high-precision turbine classifier, a cyclone collector, an electronic pulse bag dust collector, and supporting motors and electronic control components.
Application and market of barite
The main chemical composition of barite is BaSO4, BaO accounts for 65.7%, SO3 accounts for 34.3%, of which Ba will be replaced by Pb, Sr and Ca. Pure barite is colorless and transparent, but there are often impurities and various mixed substances that cause its color to change. The actual ore will appear white, gray, light red, light yellow, etc.
The characteristics of barite are high density, insoluble in water and acid, non-toxic and stable in chemical and thermodynamic properties.
Application of barite
Barite is widely used in more than ten industries such as chemical industry, electronics, building materials, metallurgy, textiles, medicine, etc. The most important role is the weighting agent of oil and natural gas drilling mud, cooling drill bits and strengthening well walls. It can prevent blowout accidents; secondly, it is the production of basic barium salts, such as barium sulfate, barium chloride, barium carbonate, and various barium compounds such as barium hydroxide, lithopone, and barium oxide.
- Oil industry
Barite can be used as a weighting agent for drilling mud to cool the drill bit and reinforce the well wall to avoid blowout accidents caused by the imbalance of mud weight and underground oil and gas pressure.
- Chemical industry
The barium salt factory uses barite as raw material to produce lithopone, precipitated barium sulfate, and barium carbonate.
- Paint industry
It can be used as a filler for paints and coatings instead of precipitated barium sulfate, lithopone, titanium dioxide, active silica and other relatively expensive raw materials. It is suitable for controlling the viscosity of the paint, and the product has a bright color and good stability. In paint, adding barite can increase the thickness, durability and strength of the paint film.
- Plastic Industry
It can be used as a filler for plastic ABS raw materials to make the product shiny and bright, and it can also improve the strength, rigidity and wear resistance of the product.
- Rubber industry
Products below 500 mesh can be used in large quantities in rubber products as fillers, reduce costs, improve product hardness, acid and alkali resistance and water resistance, etc., and have a good reinforcing effect on natural rubber and synthetic rubber.
- Paper industry
High-fineness barite powder can be used as filler and coating filler for white paperboard and copper paperboard to improve whiteness and surface coverage. Product specifications: 325 mesh, 400 mesh, 600 mesh, 800 mesh, 1250 mesh, 1500 mesh, 2000 mesh, 2500 mesh, 3000 mesh, 4000 mesh, 5000 mesh, 6000 mesh.
- Cement industry
Compound mineralizers such as barite, fluorite, gypsum, etc.
- Glass industry
Used as oxygen scavenger, clarifying agent, fluxing agent, can increase the optical stability, gloss and strength of glass.
- Architecture industry
It is used as concrete aggregate, paving material, heavy pressure on buried pipelines in swamp areas, instead of lead plates for shielding in nuclear facilities, nuclear power plants, X-ray laboratories, etc., to extend the life of roads.
- Other companies
Barite powder can also be used as a high-quality filler in ceramics and other industries.
The market for barite
The world's barite mineral resources are widely distributed and are found in more than 40 countries around the world. According to data released by the U.S. Geological Survey, as of the end of 2019, the world’s proven barite reserves were 300 million tons, of which Kazakhstan, Turkey, India, China, Iran, Thailand, Pakistan, Russia and other countries are relatively rich in resources. Accounted for 89.7% of the world's total.
Article source: China Powder Network
Precautions for the use and maintenance of the grinder
After the grinder is installed and debugged, before the operator takes over the production and operation, please read the product manual carefully, understand the structure principle of the grinder, be familiar with the performance and operating procedures of the grinder, operate strictly in accordance with the operating procedures, and follow the operating procedures and Precautions for roving inspections.
While operating in strict accordance with the operating procedures, you must also keep in mind the following tasks:
(1) The grinder motor has been lead-sealed before leaving the factory, and the coupling has been calibrated, please do not loosen it;
(2) Regularly clean the iron impurities on the permanent magnet cylinder and the permanent magnet plate of the feeder of the crusher;
(3) Regularly check the fineness of crushed products;
(4) Regularly clean or replace the dust collector bag (to ensure that the bag is ventilated), and regularly check the working condition of the solenoid valve (to see if it can work normally);
(5) Regularly check the wear and tear of the vulnerable parts of the crusher to see if it is normal wear and tear;
(6) Always pay attention to the vibration of the crusher;
(7) When the hammer of the crusher is seriously worn and needs to be replaced, pay attention to weighing to ensure that the weight difference between the two opposite hammers on the hammer pin shaft of the two opposite (1800 direction) hammers is ≤1g and the two opposite (1800 direction) hammers The total weight difference of the hammers on the pin shaft is less than or equal to 2g;
(8) When the grinder screen is severely worn and needs to be replaced, pay attention to the flatness of the new screen and whether the size of the screen is reasonable, whether the installation is in place, it is best to install the screen with the wool side facing inward;
(9) The opening degree of the air supply door of the impeller feeder should be adjusted appropriately;
(10) If abnormal conditions such as large vibration and high noise are found, the pulverizer should be shut down immediately for inspection;
(11) 80 grams of grease should be added to the spindle bearing after every 40 hours of operation, but it can only be added to 60%. After 1800 hours of operation, the bearing box cover should be removed and all used grease should be replaced. When changing to fresh grease, add grease to the area around the rollers and bearing rings, and add 1/3 to 1/2 of the grease to the bottom case. Do not add too much grease;
(12) When it is found that the output of the pulverizer suddenly drops, in addition to the factors of raw materials, check whether the air supply door is in place, whether the pipeline is leaking, whether the pulse cloth bag is blocked, whether the solenoid valve, the fan are working normally, etc.
Spherical aluminum powder classification adopts inert gas protective gas flow classifier
Ultra-fine spherical aluminum powder is mainly used in chemical raw materials, metal coatings, metal pigments, solid rocket propellants, paints, fireworks, etc. It is also used in the metallurgical industry. Inert gas shielding air current classifiers are generally used for the classification of spherical aluminum powder.
The spherical aluminum powder inert gas shielded airflow classifier has the characteristics of: fully closed circuit design, nitrogen protection low temperature operation, high classification accuracy, uniform particle size distribution, and large output. It can be widely used in tungsten carbide, cemented carbide, superhard material crushing and Graded batch production.
According to the physical characteristics of the spherical aluminum powder, a high-precision air classifier is used to precisely control the grading particle size. The characteristics of the equipment are as follows:
- Full negative pressure operation during processing, no dust pollution on site, to ensure a clean environment.
- Tungsten carbide can achieve precise control and grading, and the particle size of 1-30 microns can be adjusted arbitrarily.
- The crushing and grading accuracy of cemented carbide superhard materials can be adjusted arbitrarily between D97=3-74 microns.
- Large processing capacity, high purity and low temperature operation.
- Special airflow classifier for spherical aluminum powder inert gas protection. The entire system adopts nitrogen protection and airtight operation. The whole process is monitored by an oxygen content tester to effectively prevent the oxidation of materials.
- Adopt bag type dust removal, split back blowing, off-line dust removal, and the collection rate is over 95%, effectively reducing the loss of raw materials.
Application and market of silicon powder
Silicon micropowder is a kind of non-toxic, odorless and non-polluting silica powder processed by grinding, precision classification, impurity removal, high-temperature spheroidization and other processes as raw materials of crystalline quartz, fused quartz, etc. 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.
Classification and varieties of silica powder
Purity (%) by use and w(SiO2): ordinary silicon powder (>99%), electrical grade silicon powder (>99. 6%), electronic grade silicon powder (>99. 7%), semiconductor grade silicon powder (>99.9%) etc.
According to chemical composition: pure SiO2 silicon powder, composite silicon powder with SiO2 as the main component, etc.
According to particle shape: angular silicon powder, spherical silicon powder, etc.
In addition, there are classifications based on particle size, surface activity, etc.
- Angular silicon powder
According to the types of raw materials, it can be further subdivided into crystalline silicon powder and fused silicon powder.
Crystalline silicon powder is a silica powder material made of quartz block, quartz sand, etc., which is processed through grinding, precision classification, and impurity removal. It improves the linear expansion coefficient and electrical properties of copper clad laminates and epoxy resins. The performance of packaging materials and other products.
Fused silica powder is made of fused silica, glass, etc. as raw materials, and is made through grinding, precision classification and impurity removal processes, and its performance is greatly improved compared with crystalline silica powder.
- Spherical silica powder
Using selected angular silicon micropowder as raw material, it is processed into spherical silica powder material by flame method and other processes. It has excellent characteristics such as good fluidity, low stress, small specific surface area and high bulk density.
Compared with spherical silicon powder, the production process of angular silicon powder is relatively simple, and the application field is relatively low, so the value is relatively low; while spherical silicon powder has better fluidity, it can be used as a filler to obtain higher filling rate and uniformity, and the price Relatively high, so the price is 3 to 5 times that of angular silicon powder.
Spherical silicon powder is classified according to its particle size and can be divided into three types: micron spherical silicon powder (1-100μm), submicron spherical silicon powder (0.1-1.0μm) and nano-spherical silicon powder (1-100nm).
With the rapid development of the global electronic information industry and the continuous improvement of 4G, 5G and other technologies, higher technical requirements have been put forward for the lightness, thinness and shortness of electronic products, the packaging performance of the chip and the carrier board for carrying the chip. The spherical silicon micropowder is also moving towards Development in the direction of small particle size and excellent performance. Submicron spherical silica powder has the advantages of small particle size, proper particle size distribution, high purity, smooth surface and no agglomeration between particles, which can make up for the shortcomings of micron spherical silica powder.
Preparation methods of submicron spherical silicon powder: gas phase method, chemical synthesis method, flame method, self-propagating low-temperature combustion method, VMC method... ...
Gas phase method：the prepared product contains high impurities such as HCI and low pH. It cannot be used as the main material in electronic products. It can only be added in a small amount to adjust the viscosity and increase the strength. In addition, the raw materials are expensive, the equipment requirements are high, and the technology More complicated.
Chemical synthesis method：the prepared sub-micron spherical silicon powder is usually low in density, often contains more pores, resulting in a large specific surface area, and there are disadvantages such as the production process is not environmentally friendly.
Flame method：The raw materials used are silicon-source organics, and the safety design requirements of the feed system are stricter and the price of the raw materials is higher, which often results in higher production costs.
Self-propagating low-temperature combustion method：large-scale industrial production has not yet been achieved, and whether it can be industrialized requires further verification.
VMC method：the sub-micron spherical silica powder prepared from metallic silicon has the characteristics of smooth surface and high amorphous content. However, the raw material metallic silicon used is prone to dust deflagration, and there is a greater safety hazard in the production process.
Application and market overview of silicon powder
As a functional filler, silica powder products have unique physical and chemical properties such as high heat resistance, high insulation, low linear expansion coefficient and good thermal conductivity. They can be widely used in copper clad laminates, epoxy plastic packaging materials, electrical insulation materials, adhesives, Ceramics, coatings, fine chemicals, advanced building materials and other fields have penetrated deeply in consumer electronics, household appliances, mobile communications, automotive industry, aerospace, defense and military industry, wind power and other industries. The good development prospects of the downstream application industry provide a good guarantee for the market growth space of the silicon powder industry.
- Copper Clad Laminate
Copper clad laminate is an electronic basic material made by impregnating glass fiber cloth or other reinforcing materials with a resin matrix, one or both sides with copper foil and hot pressing. Fillers are required between the base material and the reinforcing materials. In order to improve the heat resistance and reliability of the printed circuit board (PCB board).
Silicon micropowder has excellent performance in reducing linear expansion coefficient, reducing dielectric properties, improving thermal conductivity, and high insulation. Adding silicon micropowder can improve the physical properties of printed circuit boards such as linear expansion coefficient and thermal conductivity, thereby effectively improving the performance of electronic products. Reliability and heat dissipation; and because the silicon powder has good dielectric properties, it can improve the quality of signal transmission.
At present, the filling ratio of resin in industry practice is about 50%, and the filling ratio of silicon powder in the resin is generally 30%, that is, the weight ratio of silicon powder in the copper clad laminate can reach 15%.
Copper clad laminate is a basic electronic material, and PCB is the key support for circuit components and devices in electronic products, and it is the main downstream industry of copper clad laminate. At present, PCB output value in Asia has accounted for more than 90% of the world's total, and China's PCB output value has accounted for more than 50%.
- Epoxy molding compound
Epoxy molding compound is a key material used to encapsulate chips in electronic products. The filling ratio of silicon micropowder in epoxy molding compound is between 70% and 90%. Taking the average filling ratio of 80% for calculation, the market capacity of silicon micropowder in the domestic epoxy molding compound industry is 80,000 tons.
High-performance integrated circuits have high requirements for materials, and the penetration rate of high-end silicon powder continues to increase. Ultra-large-scale and ultra-large-scale integrated circuits represented by high-end chips have extremely high requirements for packaging materials, not only requiring the use of ultra-fine fillers in packaging materials, but also requiring high purity and low radioactive element content. Traditional angular silicon micropowders have been difficult to meet the requirements. . Spherical silicon powder, especially sub-micron products, has excellent properties such as high heat resistance, high humidity resistance, high filling rate, low expansion, low stress, low impurity, and low friction coefficient, making it indispensable in ultra-large-scale and ultra-large-scale integrated circuit packaging materials. Missing functional filling materials. Therefore, the domestic semiconductor design, manufacturing, packaging and testing and other links continue to be replaced by localization, and the demand for high-end silicon powder has also grown rapidly.
- Demands for honeycomb ceramics, coatings, and high-end building materials are all in force
The main raw materials of honeycomb ceramic products are talc, microsilica powder, alumina, kaolin, cellulose, etc., and microsilica powder for coatings has also increased objectively. Silica powder has a similar structure to titanium dioxide, has excellent performance and low cost, and can effectively replace titanium dioxide.
Benefiting from the implementation of national environmental protection standards, industries such as environmentally friendly adhesives and artificial quartz panels have obtained better development opportunities. Special adhesives used in bridges and high-rise buildings, automotive ignition coil packaging, wind turbines and other fields have quickly obtained With the development, the high-end artificial quartz board industry has also improved. In addition, with the promotion of the country's circular economy and the upgrading of the green environmental protection industry, artificial marble is expected to continue to replace traditional ceramic tiles and natural stones and become a new type of advanced environmentally friendly building materials. It is predicted that in 2025, the demand for silicon powder in the field of advanced building materials may increase by 358%.
Article source: China Powder Network
Air classifier can be used to classify, break up and remove large particles
Airflow classifiers are widely used in chemical, mining, metallurgical and other industries and various dry powder materials to superfine, break up and remove large particles, and can classify spherical, flake and fibrous particles; suitable for chemical, mineral, and building materials , Electronics, pharmaceuticals, pesticides, coatings, dyes, metallurgy and other industries, can perform dry classification of various organic and inorganic substances.
The air current classifier is composed of a set of classification system with cyclone separator, dust collector and induced draft fan. The materials are first moved to the classification area from the inlet of the lower end of the air flow classifier under the suction of the fan, and then move to the classification area at a high speed with the ascending airflow. The gap of the classification wheel blade enters the cyclone separator or dust collector to collect, and the speed of the coarse particles entrained by the part of the fine particles hits the wall and disappears, and then descends along the cylinder wall to the secondary air outlet. The coarse and fine particles are separated, the fine particles rise to the classification zone for secondary classification, and the coarse particles fall to the discharge port for discharge.
Structural characteristics of air classifier:
(1) The air flow classifier is under the action of the high-speed rotating impeller with the jet fine particle ring. When the pressure of the gas flowing through the impeller rises, the high-pressure airflow will flow out of the impeller and pass through the jet fine particle ring. Curved shape, the airflow classifier has a large inlet cross-sectional area and a small outlet cross-sectional area, so the airflow pressure at the outlet is reduced, the speed increases, and it flows out in a rotating direction, which is conducive to classification.
(2) The adjustment mechanism of the air classifier is equipped with three adjustment rods, and a chain is used to keep it moving in synchronization. When the adjusting lever moves upward, the fine powder increases; when the adjusting lever moves downward, the fine powder decreases. The classification point can be continuously adjusted and the particle size of the classification product can reach D97: 3～150 microns. The air flow classifier is suitable for the fine classification of dry micron products.
(3) The control ring is equipped with a control ring to ensure that a suitable cross section is formed between the control ring and the injection fine particle ring, and the flow rate of the control airflow is stable.
(4) The residual air vent is avoided from the dry materials to bring in excess gas, and the temperature in the classification room is higher, and the air will expand, so a residual air vent is designed to keep the airflow in the classification room stable and balanced.
Application scope of air classifier:
1. The air flow classifier for high hardness materials is suitable for silicon carbide, various corundum, boron carbide, alumina, zirconia, garnet, zircon sand, diamond, etc.
2. In terms of non-metallic minerals, the air classifier is used for quartz, graphite, kaolin, calcium carbonate, mica, barite, mullite, medical stone, wollastonite, talc, pyrophyllite, etc.
3. In terms of chemical technology, aluminum hydroxide, silica gel, various dyes, epoxy resins, various additives, etc.
4. In terms of food, the jet mill is used for pollen, hawthorn, pearl powder, various vegetable powder, various Chinese herbal medicines, various cosmetics, antibiotics, etc.
5. In terms of metal materials, jet mills are also used for aluminum powder, magnesium powder, zinc powder, tin powder, copper powder, etc. Jet mills are also used in ceramic materials, refractory materials, electronic materials, magnetic materials, rare earth materials, phosphors, copy material powder, etc.
Working principle and applicable industries of airflow ultrafine pulverizer
The jet mill is a large-scale jet ultrafine pulverizer that uses airflow to carry out superfine pulverization. The jet mill, cyclone separator, dust collector, and induced draft fan constitute a complete pulverization system. The crushing process is to filter and dry compressed air into the crushing cavity through a Laval nozzle. After multiple jets of high-pressure airflow, it will form an intersection. The material is repeatedly collided, rubbed, and sheared at the intersection of the high-pressure airflow. After being cut and crushed, the crushed materials move to the classification area with the upward air flow under the action of the fan suction. Under the strong centrifugal force generated by the rotating classification turbine, the coarse and fine materials are separated, and the fine particles that meet the particle size requirements enter the cyclone through the classification wheel. The separator and the dust collector collect, and the coarse particles that do not meet the particle size requirements drop to the crushing area and continue to be crushed.
The airflow ultrafine pulverizer is more suitable for dry pulverization of various materials with a Mohs hardness of 9 or less, and is especially suitable for the pulverization of materials with high hardness, high purity and high added value. The particle size of the material crushed by the airflow ultrafine pulverizer is adjustable between D50:1~45μm, with good particle shape and narrow particle size distribution. And in the crushing process, there is no medium for low-temperature crushing, which is especially suitable for crushing heat-sensitive, low melting point, sugar-containing and volatile materials. The pulverization process of the airflow ultrafine pulverizer relies on the collision between the materials themselves, which is different from the mechanical pulverization which relies on the impact of blades or hammers on the materials, so the equipment is wear-resistant and the product purity is good.
The airflow superfine pulverization, easy disassembly and washing, smooth inside without dead corners, the pulverization process is airtight, no dust pollution, low noise, and the production process is very clean and environmentally friendly. The control system adopts program control, and the operation is simple.
Airflow ultra-fine pulverizers are widely used in chemical, mining, abrasives, refractory materials, battery materials, metallurgy, building materials, pharmaceuticals, ceramics, food, pesticides, feed, new materials, environmental protection and other industries and the ultra-fine grinding of various dry materials, It has a wide range of applications for breaking up and shaping particles.
What are the factors affecting the fineness of the jet mill
In recent years, with the development of technology, new industries have brought a ray of life. Many chemical industries and applications of ultra-fine pulverization of polymer materials (such as carbon black) will use airflow ultra-fine pulverizers. The airflow superfine pulverizer has many advantages. Under the action of the airflow, the material itself can collide to achieve the required fineness, thus ensuring the purity of the material. The better the brittleness of the material, the finer the crushing process, the greater the output.
Jet mill, also known as jet mill, jet mill or fluid energy mill, is a device that uses the energy of airflow (300-500m/s) or superheated steam (300-400℃) to pulverize solid materials. As one of the commonly used ultra-fine grinding equipment, jet mills are widely used in ultra-fine grinding and dispersing forming of ultra-hard materials such as chemical materials, medicines and foods, and metal powders.
The jet mill has a wide range of crushing particle sizes and is simple and convenient to operate. However, in the crushing process, the crushing effect is often different. The crushing effect of the jet mill is mainly affected by the following factors: gas-solid ratio, feed particle size, temperature and pressure of the working fluid, and crushing aids.
- Gas-solid ratio
The gas-solid ratio of the jet mill during smashing is an important technical parameter and also an important index. If the gas-solid ratio is too small, the kinetic energy of the air flow will be insufficient, which will affect the fineness of the product. However, if the gas-solid ratio is too high, not only energy will be wasted, but also the dispersion performance of some pigments will be deteriorated.
- Feed size
When crushing hard materials, there are also strict requirements for the particle size of the feed. As far as titanium powder is concerned, it is necessary to control 100-200 mesh when crushing the calcined material; the material after crushing surface treatment is generally 40-70 mesh, not exceeding 2-5 mesh.
- Working fluid temperature
When the temperature of the working fluid is too high, the flow rate of the gas will increase. Taking air as an example, the critical speed at room temperature is 320m/s. When the temperature rises to 480℃, the critical speed can be increased to 500m/s, that is, the kinetic energy increases by 150%. Therefore, increasing the temperature of the working fluid is beneficial to improve the crushing performance. Effect.
- Working fluid pressure
The pressure of the working fluid is the main parameter that produces the jet flow velocity, and it is also the main parameter that affects the pulverization fineness.
Generally speaking, the higher the working fluid pressure and the faster the speed, the greater the kinetic energy. The crushing pressure mainly depends on the crushability and fineness requirements of the material. For example, when superheated steam is used to pulverize titanium powder, the vapor pressure is generally 0.8-1.7MPa, while the pulverized and calcined material is generally higher, and the surface-treated material after pulverization can be lower.
Jet mills are widely used in chemical, mining, abrasives, refractory materials, battery materials, metallurgy, building materials, pharmaceuticals, ceramics, food, pesticides, feed, new materials, environmental protection and other industries and the ultrafine grinding of various dry powder materials. Dispersion and particle shape shaping have been widely used.