Use of silica

Obtained from the silica matting agent in many ways, according to its manufacturing process can be divided into two categories. One is the hydrothermal method of manufacture, production of silica morphology is relatively soft. Products made with silica gel texture is hard. After treatment, the two products can be made of standard silica matting agent. Process is the use of organic (wax) or an inorganic material to a certain degree of the silica surface modification. Compared with the silica matting agent, the treated silica with a different particle size, size distribution and pore volume. Hydrothermal method matting agent in particle size and distribution are also different. Unprocessed and processed products are different. Currently only one matting agent suitable for special occasions, the matting agent using pyrolysis manufacture, possess strong extinction efficiency, and particularly suitable for water-based coating systems.
Silica matting effect is relatively strong, higher concentrations may result in increased viscosity. A precipitate during storage of the trend, particularly in untreated silica. In order to avoid the accumulation, we can use paraffin or fumed silica. The matting agent can be adjusted 45 °, 60 ° and 85 ° azimuth extinction. Added silica matting agent can be cover coated with paint. All of these are 'stir-in' products.
Synthetic aluminum silicate can partially replace titanium dioxide used as a high-quality extender can be used in emulsion primer. The product was dried latex paint film can exhibit a balanced matting effect. In the long oil alkyd resin system can be used as a matting agent, but must be dispersed pigments and fillers. In addition to the powder coating systems, the silica matting agent can be applied to all of the coatings.

What is corundum

White fused alumina powder as raw materials in industry, at more than 2000 degrees by arc melting temperature after cooling is made by crushing plastic, magnetic separation to iron, sieving into a variety of particle size, its texture is dense, high hardness, grain formation of sharp corners form for use in manufacture of ceramics, resin bonded abrasives and grinding, polishing, sandblasting, precision casting (casting special corundum), etc., can be used to manufacture high-grade refractories, code-named "WA" on internationally accepted standards, national standards , the majority for export, there is a certain amount of supply domestic users.
Particle size in accordance with international standards and national standards of production, processing granularity according to user requirements. General size number of F4 ~ F320, depending on its chemical composition and different particle sizes. Prominent feature is the small crystal size, impact resistance, if the self-processing mill crushed particles are mostly spherical particles, dry surface cleaning, easy binding agent combination.
Corundum density:
Density is divided into two, one corundum bulk density, the second is the true density corundum.

Silica

Silica (quartzite) quartz as main mineral composition of the siliceous rocks. Manufacture of refractories refractory raw materials. 1820 by the British Young (wwYoun jealous digested first with lime made from silica sand silica, and then with British rock made of silicon silica.
Siliceous refractory silica sand can be used as raw materials for monolithic refractories.
According to the structure of dense silica is generally divided into two types of crystalline silica and silica cementation. Crystalline silica can be divided into veins of quartz and quartzite; cemented with silica quartz sandstone tunnel is divided into Shiyan and so on. By crystal transformation rate can be divided into fast, medium, slow, slow conversion of four special categories.
China Refractory materials zBD53ool at a price of silica quartz is a hexagonal Shao, also known as low-temperature quartz. Quartz is the high temperature quartz. Its crystal transition Fig. The melting point of cristobalite 1713 ℃, tridymite is 1 690 ℃.
Quartz heating process has a volume expansion of the conversion stage. Tridymite which best performance. In a more tridymite the existence of the products to form a strong skeleton. Tridymite easily soluble in the liquid phase, which makes the products, not because of the emergence of a liquid is deformed only when tridymite melted, to make products damage. So close to the softening temperature of the load of silica tridymite melting point. But to make quartz into tridymite mineralizing agent must be added to achieve. When the addition of iron scale (Feo + Fe: Oa) or flat slag can accelerate the transformation, heated to 140. ℃ above conversion intense and accompanied by a large volume expansion (when a mineralization agent), tridymite converted from the quartz, the volume expansion of 12% to 13%, without mineralizing agent, by the quartz British transforming the right volume when the prescription of 17% to 18 expansion write.
China silica rich in resources, mining more, Liaoning, Hebei, Shanxi, Shandong, Henan and other provinces. Silica generated during the grinding dust, easy to make people suffer from silicosis. Fused silica silica brick is mainly used for masonry carbonization chamber coke ovens and glass melting furnace, open-hearth furnace regenerators, etc., in the 1950s and before, are used for open-hearth furnace roof, brick after alkaline replaced.

Benefits and use of corundum

Corundum benefits: a high temperature, corrosion resistance, high strength and other properties, it poured with steel sliding gate, smelting rare metals, special alloys, ceramics, blast furnace lining (walls and tubes); chemical containers, spark plugs, anti- Thermal oxidation coating.
1, corundum is called dental industry: mainly used in the refractory, grinding wheels, sand blasting.
Sandblasting corundum - blasting abrasive hardness, high packing density, no free silica, heavy, good toughness, Okay corundum is the ideal "green" blasting material, widely used in aluminum, copper profiles of glass, washed jeans precision molds and other fields;
2, free grinding - grinding grade abrasives used in kinescope, optical glass, silicon, lenses, clocks, glass, crystal glass, jade and other areas of freedom ground, is commonly used advanced abrasive material;
3, resin abrasive - Abrasive have the right color, hardness, toughness, suitable particle section types and edge retention, resin abrasive used, the results are satisfactory;
4, Coated Abrasives - Abrasive sandpaper, gauze and other manufacturers of raw materials;
5, corundum functional filler - mainly used for automobile brake parts, specialty tires, specialty building products in areas such as construction of motorways, runways, terminals, parking lots, industrial flooring, sports and other wear-resistant materials ;
6. the filter media - is a new type of abrasive applications, the use of particulate abrasive medium as the bottom of the filter bed, to purify drinking water or waste water, is home to a new water filtration material, especially for non-ferrous metal processing, oil drilling mud weighting agent :
7, abrasive water-jet cutting - is abrasive cutting media, relying on high-pressure water jet cutting basic, used in oil (gas) pipelines, steel and other components of the cutting, is a new, environmentally friendly, safe cutting.
Customers: washing plant denim sandblasting workshop shipyard shipyard steel plant powder factory Shalun sandpaper, emery cloth factory floor crystal glass industry building industry, steel industry, metal industry, electronics industry, Qi car manufacturing docks, parking Hospital Stadium. Spray sands industry and other cooperation to meet various user needs in aggregate and abrasive floor.

The main function of corundum

(1) Due to high temperature, corrosion resistance, high strength and other properties, it poured with steel sliding gate, smelting rare metals, special alloys, ceramics, blast furnace lining (walls and tubes); chemical containers, spark plugs, thermal oxidation resistant coating.
(2) Because of hardness, wear resistance, high strength characteristics, in chemical systems, used a variety of responses utensils and pipes, chemical pump parts; doing mechanical parts, various molds, such as wire drawing dies, extrusion die nozzle pencil, etc.; make tools, dies abrasive, bulletproof material, human joints, sealing ring mold.
(3) corundum insulation materials, such as lightweight corundum bricks, corundum hollow spheres and fiber products, widely used in various high-temperature kiln furnace wall and roof, both high temperature insulation.
Size sand corundum corundum block by artificial selection, using the roll, milling, processing Barmac other equipment, particle size by the F8-F325. Mainly used for polishing, grinding, industrial grinding, etc., can also according to customer requirements for washing, pickling and other processing methods to meet the different needs of customers.

Green silicon carbide abrasives uses and characteristics

Green silicon carbide is quartz sand and coke for raw materials as a good thermal conductivity, high hardness of man-made materials. Green silicon carbide even at high temperatures with high strength, the elastic modulus when the temperature reaches 1600 ℃, only begins to decay. At a temperature of 2815 ° C begin to separate, but it does not melt at atmospheric pressure. Green silicon carbide suitable for use as super refractories, is also widely used for grinding areas.
Uses: 3-12 inch monocrystalline silicon, polycrystalline silicon, GaAs, quartz crystal wire cutting. Solar photovoltaic industry, the semiconductor industry, piezoelectric crystal engineering of industrial processing materials.
Features:
1, high-purity, large crystal silicon carbide material, the cutting of silicon carbide powder to ensure excellent cutting performance and stability of the physical condition.
2, plot size and shape of such a front edge, to ensure cutting edge material as silicon carbide powder balanced self-sharpening to ensure the material being cut TTV is minimized.
3, the particle size distribution is narrow and uniform.
4, a high thermal shock resistance and load softening temperature, which ensures that the cutting load of the small coefficient of linear expansion, thus ensuring the stability of the cutting; cutting machines and able to have a good adaptation of.
5, the surface is specially treated, powder with a large specific surface area and clean appearance, and polyethylene glycol coolant has good suitability.

The nature of quartz sand structure and classification

Quartz sand is a hard, wear-resistant, chemical stability of silicate minerals, the main mineral component is SiO2, quartz sand color is white or colorless, translucent, hardness 7, brittle no cleavage, conchoidal fracture, oil sheen, the relative density of 2.65, its chemical, thermal and mechanical properties have obvious anisotropy, acid-insoluble, slightly soluble in KOH solution, melting point 1750 ℃.
Quartz can be classified according to the quality of ordinary quartz sand, fine quartz sand, high purity quartz sand, fused silica sand.
1, ordinary quartz sand:
SiO2 ≥ 90-99% Fe2O2 ≤ 0.06-0.02%, refractoriness 1750 --- 1800 ℃, the appearance of some large particles, the surface of yellow cysts. Particle size range 5-220 mesh, users can request granularity production. Main purpose: metallurgy, ink silicon carbide, glass and glass products, ceramic, steel, water filtration, sodium silicate, chemical, jet noise and other industries.
2, refined quartz sand:
SiO2 ≥ 99-99.5% Fe2O3 ≤ 0.02-0.015%, selected high-quality ore complex processing. With 5-480 mesh size range, according to user requirements, the appearance of a white or crystalline. Main purpose: High quality glass, glass, refractories, smelting stone, precision casting, grinding wheel and other materials.
3, high purity quartz sand:
SiO2 ≥ 99.5-99.9% Fe2O2 ≤ 0.005%, is the use of 1-3 grade natural crystal stones and high quality natural stone, carefully selected, fine processing. Particle size range of 1-0.5mm, 0.5-0.1mm, 0.1-0.01mm, 0.01-0.005mm, according to user requirements.
4, fused quartz sand
Chemical composition: SiO2 99.9-99.99% Fe2O3 10PPM-25PPM maxLi2O 1-2PPM maxAl2O3 20-30PPM maxK2O 20-25PPM maxNa2O 10-20PPM max Physical Properties: colorless transparent block, granules or white powder. True specific gravity: 2.21; Mohs hardness: 7.0; PH value: 6.0.

Corundum and widespread use of the chemical composition

The origin of most of the bauxite and corundum origin are closely related. Rich country of Henan bauxite, bauxite production giant, it has also become the largest producer of corundum area. Corundum has a hardness, toughness, resistance to crushing ability, high temperature, anti-oxidation, anti-corrosion, low cost, for other characteristics.
Corundum widely used in abrasives, refractories, sandblasting, grinding and polishing, carborundum wearable Floor, precision casting shell mold making, with high purity, good crystalline liquidity strong, low coefficient of linear expansion, corrosion-resistant characteristics .
Brown fused aluminum oxide (Al2O3) is not less than 92.5% corundum widely often used in wear industry, which there are many types, the most common is washed corundum.
Corundum is often used in an ink jet washing of production, this is because, under extreme pressure, it can use its sharp corners hit the surface which is the other advantages not corundum. Then washed for inkjet corundum dust generated when handling relatively small, to a certain extent, to ensure the operator's health. As slag relatively brittle, the jet mill process, the formation of small particles easily crashing, relatively small proportion of the slag, slag resulting small particles suspended in the air, causing environmental pollution, too, is a very delicate quartz sand abrasive, but definitely not comparable and corundum.

Corundum main function

(1) Due to high temperature, corrosion resistance, high strength and other properties, it poured with steel sliding gate, smelting rare metals, special alloys, ceramics, blast furnace lining (walls and tubes); chemical containers, spark plugs, anti- Thermal oxidation resistant coating.
(2) Because of hardness, wear resistance, high strength characteristics, the chemical system, the various reactions used utensils and pipes, chemical pump parts; doing mechanical parts, various molds, such as wire drawing dies, extrusion die nozzle pencil, etc.; make tools, dies abrasive, bulletproof material, human joints, sealing ring mold.
(3) corundum insulation materials, such as lightweight corundum bricks, corundum hollow balls and fiber products, widely used in various high-temperature kiln furnace wall and roof, both high temperature insulation.
Size sand corundum corundum block by artificial selection, using the roll, milling, processing Barmac other equipment, particle size by the F8-F325. Mainly used for polishing,
After the blast furnace carbon corundum and special process of re-treatment, reducing the residual carbon content of corundum, the product is not in use powder, not burst, toughness is the abrasives industry, refractory materials industry of choice. Mainly used in ceramic abrasive, high-grade abrasive, organic abrasive, abrasive belt, coated abrasives, etc., according to the residual carbon content is divided into: calcined corundum C ≤ 0.05%, carbon corundum C ≤ 0.10%, ordinary brown corundum C ≤ 0.15%.
grinding, industrial grinding, etc., can also according to customer requirements for washing, pickling and other processing methods to meet the different needs of customers.

White fused alumina production process

Corundum smelting mainly frit France and dumping French.
Corundum and corundum smelting different points:
Production of white fused alumina, white fused alumina lining construction materials commonly used sand or aluminum oxide powder.
Access package of linerless access package and have access package liner. Linerless access package to force water, there are generally lined with graphite or white fused alumina refractory products for the bag lining.
Frit production of corundum, lining require good thermal insulation performance, and good ventilation, furnace divided into two kinds of liners and no lining.
There are generally require the use of sintered products lining, no lining heat loss larger, generally accounting for more than 24% of energy consumption, backed heat loss accounted for only about 4%.

Corundum refractories used in

Brown fused alumina is a high-grade synthetic material. Is the use of high-quality bauxite as main raw material, coke, iron and other auxiliary materials, high-temperature smelting in electric arc furnace purified from.
Generally were brown corundum, Al2O3 ≥ 94.5%, SiO2 ≤ 2.5%, TiO2 ≤ 3.5%, Fe2O3 ≤ 1%, mineral composition to α-Al2o3 main center of the diamond-shaped crystal, slab type and with crack particles have more peripheral silicon oxide, calcium Melt Crystallization, elongated plate, the coarse crystal grains become skeletal-like sheet. Corundum hue is largely dependent on the remnants of the titanium oxide.
Corundum is mainly used as an abrasive. Refractory materials have been widely used in recent years, such as hooks castable, no blisters mud, corundum brick, precast, air brick, ladle brick, magnesia carbon bricks.
Brown fused alumina for refractory aggregate and powder is generally used to do, it has the advantage of high refractoriness, wear resistance, erosion, corrosion resistance, bulk density, high alumina content, mainly for aluminum lines and alumina. When do products have a high load softening temperature and high-temperature dimensional stability. But corundum impurities in the products in the course of life. Since smelting impurities not removed completely, so corundum also contains six calcium aluminate, calcium plagioclase, spinel, rutile and other times crystalline phase and glass phase, ferro alloys and solid solutions. In a large sense, corundum smelting process and smelting time determines the performance and quality of its products.

Green silicon carbide wheel replacement process and other considerations Precautions during replacement

Any grinding wheel wear problems has its use of a certain wear requirements, wear reaches a certain level must be re-replacement of the grinding wheel. Not in order to save material, it requires the use of ultra-wear, which is a very unsafe violations. General rule, when the wheel wear to chuck diameter than the diameter of 10mm, it should be replaced with new wheel. Valid questions from the Treasury brought out a new wheel is not necessarily qualified wheel, or even buy a new wheel from the factory are not necessarily qualified wheel. Any wheel has its certain expiration date, the expiration date of use, it is qualified wheel; than valid to use, it is not necessarily qualified wheel. Statutes provides that "wheel should be used within the validity period, resin and rubber bonded grinding wheel storage after one year must be approved by rotation test, those who pass before using." Texture problems in the course, if we find the local wheel cracks should immediately stop using and re-replacement of the grinding wheel, grinding wheel to avoid crushing injury accident.
Other Precautions
Environmental issues grinder wheel should generally be set up private room, and is prohibited in the room or grinder wheel stacked near flammable items, to avoid fire or explosion, nor should a grinder near misplacing other parts or items. Management issues should be specifically responsible grinders, where non-unit personnel wishing to grinder to grind objects, subject to full-time person in charge of licensing and strict compliance with safety procedures, is strictly prohibited without the consent of the responsible officer, unauthorized outsiders mess with grinders. In addition, the wheel should also be specifically responsible for replacement, prohibit others from unauthorized change, installation of wheel. Shutdown problem after the operator stops working, you should immediately turn off the car. In the absence of prohibited use grinders, unattended case idling. In addition, after use should be kept shortwave turbine clean.
Shape can be divided according to level grinding wheels, bevel wheel, cylindrical grinding wheels, cup wheels, disc wheel, etc.; binding agents can be classified according to the ceramic grinding wheel, resin grinding wheel, rubber wheel, metal grinding wheel. The wheel parameters are abrasive, viscosity, hardness, binders, shape, size and so on. Since wheel usually work at high speed, thus turning test should be carried out before use (guaranteed wheel at the maximum operating speed, not break) and static balance test (to prevent machine vibrations caused by the work). Grindstone at work for some time, should be trimmed to restore grinding performance and correct geometry.

The main function of corundum

(1) Due to high temperature, corrosion resistance, high strength and other properties, it poured with steel sliding gate, smelting rare metals, special alloys, ceramics, blast furnace lining (walls and tubes); chemical containers, spark plugs, thermal oxidation resistant coating.
(2) Because of hardness, wear resistance, high strength characteristics, in chemical systems, used a variety of responses utensils and pipes, chemical pump parts; doing mechanical parts, various molds, such as wire drawing dies, extrusion die nozzle pencil, etc.; make tools, dies abrasive, bulletproof material, human joints, sealing ring mold.
(3) corundum insulation materials, such as lightweight corundum bricks, corundum hollow spheres and fiber products, widely used in various high-temperature kiln furnace wall and roof, both high temperature insulation. Size sand corundum corundum block by artificial selection, using the roll, milling, processing Barmac other equipment, particle size by the F8-F325. Mainly used for polishing, grinding, industrial grinding, etc., can also according to customer requirements for washing, pickling and other processing methods to meet the different needs of customers.

Silicon carbide powder production steps are as follows

Silicon carbide powder production process
Silicon carbide powder production process there are five main steps:
First, take the silicon carbide materials, through the crusher, and sieved to less than 5mm of silicon carbide particles, and then shaping machine shaping them to no more than 2mm of silicon carbide particles, and the particles of which accounted for 80 Oval % or more, performs, pickling to remove impurities, and then during drying
Second, milling, the dried particles of silicon carbide powder mill crushed into d50 = 9.5-11.5μm silicon carbide powder, crushed when the mill is set to host the current 65-75A, fan flow is set to 40-50m3/min, analysis machine speed of 400 - 600 rpm / min for milling process.
Third, grading, grading machine with vortex flow silicon carbide powder grading, grading, vortex flow fan air classifier is 25-43m3/min, classifier wheel rotational speed of 2600 - 3300 rev / min, from grading mouth ceded ds94 = 6.5-5.5μm particle size of the finished product A, cyclone separation ds94 ≤ 5.5μm mouth semi-finished products;
Fourth, the vortex type air classifier with cyclone mouth impeller semi separated gas stream classifier then re-classifying, grading, the impeller of the fan air flow classifier 25-10m3/min, classifier wheel rotation speed is 1300 - 1700 rev / min, separated from the particle size classification mouth ds94 = 4.5-3.0μm finished product B, then the separated product cyclone mouth. Fifth, testing, according to the standard detected in the production of silicon carbide powder is qualified.

Abrasive Equipment selection tips

With the rapid development of the domestic photovoltaic industry, which use ultra-fine abrasive for cutting demand is growing. The current production equipment for the mainstream ultra-fine abrasive jet mill, Raymond mill, etc.
From the perspective of air grinder fineness certainly better than Raymond crushed to fine jet mill can crush the limit can be up to 6,000 head of fine, but the jet mill Raymond relatively high in terms of energy consumption.
From the production is concerned, when the production of high-grade powder jet mill production is higher than Raymond.
Thus, the abrasive equipment selection process, then only consider the production, relatively better choice jet mill; if from the energy point of view, then select Raymond better.
From the actual production situation, high value-added abrasive powder production is a key component grading system. Good performance grading system in a timely, clean surplus powder extract classification.
Grading systems have become a key production, mainly because of large particles of abrasive industry taboo - finished grading requirements absolutely no large particles appear.
Raymond is now the industry because the manufacturers do more for machinery manufacturing experts, mainly for the study of aerodynamic airflow grading equipment advantage is not obvious, therefore, the current high-grade powder jet mill is still mainly based.

Silicon carbide powder production process

Silicon carbide powder production steps are as follows:
Silicon carbide powder production process there are five main steps:
First, take the silicon carbide materials, through the crusher, and sieved to less than 5mm of silicon carbide particles, and then shaping machine shaping them to no more than 2mm of silicon carbide particles, and the particles of which accounted for 80 Oval % or more, performs, pickling to remove impurities, and then during drying
Second, milling, the dried particles of silicon carbide powder mill crushed into d50 = 9.5-11.5μm silicon carbide powder, crushed when the mill is set to host the current 65-75A, fan flow is set to 40-50m3/min, analysis machine speed of 400 - 600 rpm / min for milling process.
Third, grading, grading machine with vortex flow silicon carbide powder grading, grading, vortex flow fan air classifier is 25-43m3/min, classifier wheel rotational speed of 2600 - 3300 rev / min, from grading mouth ceded ds94 = 6.5-5.5μm particle size of the finished product A, cyclone separation ds94 ≤ 5.5μm mouth semi-finished products;
Fourth, the vortex type air classifier with cyclone mouth impeller semi separated gas stream classifier then re-classifying, grading, the impeller of the fan air flow classifier 25-10m3/min, classifier wheel rotation speed is 1300 - 1700 rev / min, separated from the particle size classification mouth ds94 = 4.5-3.0μm finished product B, then the separated product cyclone mouth. Fifth, testing, according to the standard detected in the production of silicon carbide powder is qualified.

High-plated clothing abrasive corundum little knowledge

Corundum coated abrasive is a low-cost clothing for abrasive can effectively improve the performance of the method and process, this abrasive widely used in coated abrasives and resin bonded abrasives manufacturing.
Production process:
This product uses iron oxide red and vitrified Stir with a high-pressure spraying equipment, evenly coated in corundum surface, and to thin and uniform coating, the coating is too thick, then prone to shedding.
Specific production process is as follows:
Raw grain of sand → washing → iron oxide red vitrified metering metering → → → mixing → corundum mixing temperature firing temperature curing → → screening → packing.

Silicon carbide production process

Silicon carbide is produced silica reduction method, the Acheson furnace for resistance, is silica sand and coke in an electric furnace heated to a high temperature of about 2600 degrees carried out, of the formula
sio2 +3 c-sic +2 co
Wherein in the smelting process of CO burn all, in order to improve the permeability of the furnace, usually in the raw materials by adding a small amount of sawdust.
Green silicon carbide in the smelting process, require a relatively high purity silica sand, companies need to add a little salt.
Mainly in the graphite furnace electrode.
The overall process is the charge reaction, the production of silicon carbide and carbon monoxide, which burn carbon monoxide in the reaction, as the reaction proceeds, silicon carbide gradually increased, forming a crystalline tube, the reaction was completed, remove the furnace wall, the outer pull impurities out, the internal shiny crystals is silicon carbide.

Corundum refractories used in

Brown fused alumina is a high-grade synthetic material. Is the use of high-quality bauxite as main raw material, coke, iron and other auxiliary materials, high-temperature smelting in electric arc furnace purified from.
Generally were brown corundum, Al2O3 ≥ 94.5%, SiO2 ≤ 2.5%, TiO2 ≤ 3.5%, Fe2O3 ≤ 1%, mineral composition to α-Al2o3 main center of the diamond-shaped crystal, slab type and with crack particles have more peripheral silicon oxide, calcium melt Crystallization, elongated plate, the coarse crystal grains become skeletal-like sheet. Corundum hue is largely dependent on the remnants of the titanium oxide.
Corundum is mainly used as an abrasive. Refractory materials have been widely used in recent years, such as hooks castable, no blisters mud, corundum brick, precast, air brick, ladle brick, magnesia carbon bricks.
Brown fused alumina for refractory aggregate and powder is generally used to do, it has the advantage of high refractoriness, wear resistance, erosion, corrosion, bulk density, high alumina content, mainly for aluminum lines and alumina. When do products have a high load softening temperature and high temperature volume stability. But corundum impurities in the products in the course of life. Since smelting impurities not removed completely, so corundum also contains six calcium aluminate, calcium plagioclase, spinel, rutile and other times crystalline phase and glass phase, ferro alloys and solid solutions. In a large sense, corundum smelting process and smelting time determines the performance and quality of its products. 

The basic varieties of silicon carbide

Black silicon carbide and silicon carbide green silicon carbide two common basic varieties, are of α-SiC, SiC there are 75 kinds of variants, all of these structures can be divided into cubic, hexagonal and rhombohedral.
Wherein the α-SiC, β-SiC is most common. α-SiC is a high temperature stable, β-SiC is temperature stable. β-SiC at 2100 ~ 2400 ℃ can be transformed into α-SiC, β-SiC at about 1450 ℃ temperature by a simple mixture of silicon and carbon in the system.
Using transmission electron microscopy and X-ray diffraction techniques can be performed on the body of SiC polytypes microscopic analysis and quantitative determination of silicon carbide powder is mainly used for primary products and high heat ceramic materials in the field, is a high energy product, the country has been canceled silicon carbide powder 5% export tax rebates.
① black silicon carbide SiC containing approximately 98.5% higher than its toughness green silicon carbide, mostly for processing low tensile strength of the material, such as glass, ceramics, stone, refractory materials, cast iron and non-ferrous metals.
② green silicon carbide containing SiC99% or more, good self-sharpening, mostly used for machining tungsten carbide, titanium and optical glass, also used for honing cylinder liners and grinding high-speed steel cutting tools. There is also cubic silicon carbide, which is based on a special process to take the yellow-green crystals, suitable for the production of abrasive bearing super finishing, make the surface roughness Ra32 ~ 0.16 microns from primary processing to Ra0.04 ~ 0.02 microns.
Silicon carbide has four major application areas, namely: functional ceramics, advanced refractories, abrasives and metallurgical raw materials. Currently most enterprises are still in silicon carbide roughing state.

The basic varieties of silicon carbide

Black silicon carbide and silicon carbide green silicon carbide two common basic varieties, are of α-SiC, SiC there are 75 kinds of variants, all of these structures can be divided into cubic, hexagonal and rhombohedral.
Wherein the α-SiC, β-SiC is most common. α-SiC is a high temperature stable, β-SiC is temperature stable. β-SiC at 2100 ~ 2400 ℃ can be transformed into α-SiC, β-SiC at about 1450 ℃ temperature by a simple mixture of silicon and carbon in the system.
Using transmission electron microscopy and X-ray diffraction techniques can be performed on the body of SiC polytypes microscopic analysis and quantitative determination of silicon carbide powder is mainly used for primary products and high heat ceramic materials in the field, is a high energy product, the country has been canceled silicon carbide powder 5% export tax rebates.
① black silicon carbide SiC containing approximately 98.5% higher than its toughness green silicon carbide, mostly for processing low tensile strength of the material, such as glass, ceramics, stone, refractory materials, cast iron and non-ferrous metals.
② green silicon carbide containing SiC99% or more, good self-sharpening, mostly used for machining tungsten carbide, titanium and optical glass, also used for honing cylinder liners and grinding high-speed steel cutting tools. There is also cubic silicon carbide, which is based on a special process to take the yellow-green crystals, suitable for the production of abrasive bearing super finishing, make the surface roughness Ra32 ~ 0.16 microns from primary processing to Ra0.04 ~ 0.02 microns.
Silicon carbide has four major application areas, namely: functional ceramics, advanced refractories, abrasives and metallurgical raw materials. Currently most enterprises are still in silicon carbide roughing state.

The role of silicon carbide

Silicon carbide industrial system is high-quality quartz sand and petroleum coke in a resistance furnace refining. Lian obtained silicon carbide blocks, crushing, acid washing, magnetic separation and screening or water election into various size products.
SiC as chemical stability, high thermal conductivity, thermal expansion coefficient, good wear resistance, except for the abrasive used, there are many other uses.
For example: a special process of the silicon carbide powder coating on the turbine impeller or the inner wall of the cylinder, to improve the wear resistance and extended life of 1 to 2 times.
Made for advanced refractory, thermal shock resistance, small size, light in weight, high strength, good energy saving effect.
Low-grade silicon carbide (SiC-containing about 85%) is an excellent oxygen scavenger, it can accelerate the speed steel, and facilitate control of chemical composition and improve the quality of steel. In addition, silicon carbide heating element is also used extensively for production of silicon carbide.

Calcined corundum abrasives advantages

1, the elimination of the aluminum oxide abrasive abnormal expansion: As in the smelting process of fused alumina abrasive containing low-cost titanium (Ti 0, TiO) and titanium carbide, titanium nitride (Tic, TiN), their 1000% to 900% of a calcined in an oxidizing atmosphere, it will further oxidation, the volume increases accordingly, the volume change of the abrasive itself beyond its normal expansion, the expansion is abnormal.
Abnormal expansion of the abrasive, the ceramic corundum grinding wheel causes the firing, the surface mesh cracks, resulting in a large waste, and the use of calcined aluminum oxide abrasive to eliminate anomalous expansion of the most effective means.
2, to improve the toughness of the aluminum oxide abrasive and grinding performance: The study found, this is due to the abrasive in the calcination process, the first corundum crystalline solid melting at the TI3 + is oxidized and cause contraction of the lattice, thereby increasing the abrasive resistance compressive strength, followed by calcination in the granulation process will make the internal stress caused.
Thus, after calcination produces a variety of abrasive grinding tools, not only durable and sharp increases abrasive grinding performance.

The main purpose of silicon carbide powder

Silicon carbide powder is widely used in refractory wear-resistant flooring, ceramic foam, specialty coatings, corrosion-resistant paint, flow separation and environmental protection industries,
While the production of silicon carbide ultra-fine powder of silicon carbide ceramics ideal material. Silicon carbide ceramics have excellent mechanical properties at room temperature, such as high bending strength of excellent oxidation resistance, corrosion resistance, a very high wear resistance and a low coefficient of friction and high temperature mechanical properties, such as silicon carbide whisker reinforcement can be improved toughness and strength.
Since silicon carbide excellent physical and chemical properties, so that in petroleum, chemical, microelectronics, automotive, aerospace, laser, atomic energy, machinery and metallurgy industry, widely applied.
Such as wheels, nozzles, bearings, seals, turbine blade movement, the substrate reflective screen, engine parts, refractories.