Recent developments in green silicon carbide

Green silicon carbide as an abrasive, silicon carbide production area in our previous two or three decades was a hero, and later as for export purposes and silicon carbide grinding non-development, production volume relative to the black silicon carbide, gradually relegated secondary position.
But its total production is always rising steadily, especially in the late 1990s, the international wire cutting of green silicon carbide powder application process, our green silicon carbide production and exports have increased, but producing regions and manufacturers also limited to the traditional Northeast Mudanjiang, Hun, etc., the Central Plains, Zhengzhou, Pingdingshan, Shandong Tengzhou, linshu and Hubei Danjiangkou, etc., the Northwest Territories and only Qinghai Guide Haiyan and Blackforge change Green furnace of LAI.
Another turn of the century before, not on the use of Sichuan power grid small hydro electricity low (from the 0.08 to 0.15 yuan / KWH), from Shandong, and Fujian in Lianyungang Miannig, ganluo and Johnson and Yaan, etc., to build a batch furnace capacity 6300KVA ~ 2000KVA green silicon carbide smelter home.
So far, China's annual output of green silicon carbide by the reform and opening up to the time of less than three tonnes to seven or eight tons. But the biggest single furnace capacity still hovering at 5000 ~ 6300KVA, smelting process also follows the formation of the sixties and the East China Sea petroleum coke calcination quartz sand as raw material processes.

Garnet evaluation and appreciation

Garnet in color, transparency, clarity, weight and other aspects of its cut quality evaluation standards, excellent product requires pure color beautiful, clean and transparent interior, flawless crack, cut well and have some weight.
(1) Color: The color to be pure and beautiful. Different varieties, different colors, values ??are different. As rare demantoid, chrome vanadium grossular other green varieties if transparent without cracking, high quality and high quality emerald may equal value; red pyrope, orange spessartine, Hessonite also valuable, and maroon, dark red almandine lower value.
(2) Transparency: high quality person should be transparent and clean. Translucent or color depth are often processed into a concave arc in order to increase transparency. While opaque to translucent varieties to check the internal arrangement of inclusions see if processed into cabochon while showing a starlight effect.
(3) Clarity: To no cracks, flaws, especially a lot of dark red almandine. Complete crystal partakers who pay attention to whether the internal structure or folder with black opaque inclusions agglomerate. Such as Vietnam output intact skin only to garnet crystal thin transparent can be utilized for other mineral impurities within the black heart. At present, high-quality garnet mostly irregular silicon carbide grit.
(4) Weight: raw block the bigger the better, rounded shapes to mix better, which can improve the processing yield. Right Demantoid green grossular other high-grade varieties, the price increases exponentially with the weight, usually more than 0.5ct very valuable; while other species with different weight finished their prices changed little, mainly to see required when making jewelry styles and sizes requirements. But a few rare giant crystal or finished products can be regarded as treasures. (5) Cut: To fashionable, proper proportion, polish well. Different varieties of materials to be designed for different styles. High dispersion Demantoid processed into standard round brilliant, in order to fully reflect its fire color; coloration were processed for the double curved to enhance the body color; color depth are processed in order to lighten the color of the concave arc, increasing transparency; has multiple sets of special needles arranged in the direction of the arc-shaped inclusions processing to display the star effect.

Silicon carbide industry's position in the slice

Crystalline silicon photovoltaic feeder line cutting is cutting the biggest market differentiator, and silicon carbide crystal wafer cutting is very important as an accessory, the market demand with the development of photovoltaic industry has maintained a strong growth momentum. However, since entering in May, silicon carbide market prices began to loosen, product demand dropped, companies have been affected to varying degrees. Henan Green foreign filter water treatment materials industry professionals once said: "silicon carbide powder is a tool in the hands of photovoltaic enterprises, who have the best tools, whoever occupies the best cutting opportunities."
It is obvious from this statement in the slice of silicon carbide powder industry position is pivotal. With the rapid development of photovoltaic industry, the industry's growing demand for wafer temperature, the number is growing, while the production of polycrystalline silicon carbide powder as an important accessory, its natural demand is increasing. Domestic silicon carbide powder is mainly divided into black silicon carbide powder and green silicon carbide powder into two categories, the black silicon carbide powder and green silicon carbide powder technology and ingredients are different, resulting in the market demand for these two products is not the same.
At present, mainly dominated by green silicon carbide powder, because it itself determines its characteristics more suitable for photovoltaic, semiconductor crystal silicon material cutting edge parts, so the use of green silicon carbide powder than black silicon carbide powder. Our country is a major exporter of silicon carbide production and, in 2009 total output of 530,000 tons of silicon carbide and more, accounting for 56.3% of the global total, ranking first in the world. 2010 silicon carbide production reached 700,000 ~ 800,000 tons, as of now, 2011 silicon carbide production has reached 30 million to 40 million tons.

About corundum abrasive characteristics and processing technology introduction

Corundum abrasives, white fused alumina, white fused alumina block, abrasive corundum, white corundum sand (WA)
White fused alumina abrasive is alumina as raw materials, high temperature melting together. White, slightly higher hardness than corundum, lower toughness. Made with corundum abrasive for high carbon steel, high speed steel and hardened steel grinding. Corundum abrasive, white corundum abrasive polishing material can be used, but also for precision sand casting, coating materials, chemical catalyst carrier, special ceramics, advanced refractories.
White fused alumina abrasive chemical composition:
Chemical composition size range AI2O3 (%) Na2O (%)
F12 - F80 ≥ 98.5 ≤ 0.50
F90 - F150 ≥ 98.5 ≤ 0.60
F180 - F220 ≥ 98.2 ≤ 0.70
Physical properties of corundum abrasives: Physical property
Basic mineral crystal size μm really infer g/cm3 Bulk density g/cm3 microhardness g/mm2
α-AI2O3 600 ~ 1400 ≥ 3.90 1.5 ~ 1.95 2200 ~ 2300
Corundum abrasive properties: white, hard and brittle than corundum, strong cutting force, good chemical stability, with good insulation. White fused alumina abrasive Scope: do solid structure and coated abrasives, wet or dry spray sand, suitable crystals, the electronics industry and ultra-fine grinding and polishing production advanced refractory. Suitable for machining hardened steel, alloy steel, high speed steel, high carbon steel and other hard hardness, tensile strength greater material. Corundum abrasives can also be used as catalyst, insulators and precision casting sand.

Silicon carbide is the most widely used and most economical product

Silicon carbide (SiC) with quartz sand, petroleum coke (or coal), wood chips as raw material in electric arc furnace smelting. There are also rare in nature, silicon carbide mineral, Moissanite. Silicon carbide, also known as Moissanite.
In contemporary C, N, B and other high-tech non-oxide refractory raw material, silicon carbide is the most widely used and most economical one. Can be called emery or refractory sand. Silicon carbide is quartz sand, petroleum coke (or coal), wood (green silicon carbide production requires add salt) and other raw materials at high temperature in a resistance furnace smelting. At present, China's industrial production is divided into black silicon carbide and silicon carbide green silicon carbide two kinds, both hexagonal crystal, specific gravity of 3.20 ~ 3.25, microhardness 2840 ~ 3320kg/mm2.
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 the silicon carbide powder coating on the turbine impeller or cylinder block wall, can improve the wear resistance and extended service life 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.
Silicon carbide is also used extensively for production of silicon carbide heating elements.

Corundum: corundum density related presentations

Corundum density:
Density is divided into two, one corundum bulk density, the second is the true density corundum. 
Bulk density:
1.53 ~ 1.99g/cm3, the bulk density of the abrasive and the abrasive grain size, grain size, species, particle shape and other factors are, in general, coarse abrasive bulk density than the fine-grained abrasive, mix size is greater than the bulk density of the abrasive single particle density.
Particle density:
3.95 ~ 4.0g/cm3, in recent years, special casting corundum true density has reached 4.1g/cm3, the true density of the abrasive is the unit volume (excluding the volume of open porosity) contained within the abrasive quality, primary particle size of as follows: 45% to 55%, corundum can rest assure that more than 50%, the basic effect of particle size is an important indicator to ensure the ground, should be properly controlled in the production, but the production speed may slow down.

 

Silicon carbide and corundum abrasives on the characteristics and performance description

1, brown fused alumina:The main chemical composition AL2O3, the bauxite, iron and anthracite from melting in an electric arc furnace. Corundum abrasive color is brown, its color, the name corundum. The abrasive has a certain hardness and toughness, with the strong grinding ability, able to withstand great pressure. With a high temperature, anti-oxidation, anti-corrosion and chemical stability is good. High tensile strength as it applies to the grinding of the material tensile strength, suitable for general steel, high carbon steel, alloy steel, for the processing of hard wood, other abrasives can be used in substitution is insufficient, a universal Abrasive said, is the most widely used kind of abrasive.2, corundum:The main chemical composition of AL3O2 aluminum oxide powder as raw material in electric arc furnace melting together. Color is white, in terms of its color name corundum. Corundum corundum texture purer than brown. Using aluminum oxide powder material, corundum used by the Department of bauxite processing is made in advance, the main physical components (without grinding capacity) by arc melting from the converted. The conversion has strong grinding force.3, black silicon carbide:The main chemical composition of SiC. From petroleum coke, quartz sand, sawdust as raw materials in the resistor formed by the melting furnace. Black silicon carbide color is black, in terms of its color, named for the black silicon carbide. Black silicon carbide is brittle texture than corundum abrasive, hardness hard, its toughness is also inferior to corundum abrasive, than the end of the tensile strength of the material, such as non-metallic materials (various boards such as wooden plywood, particleboard, high school low-density fiberboard , bamboo board, calcium silicate board, leather, glass, ceramics, stone, etc.) and non-ferrous metals (aluminum, copper, lead) and other materials processing is particularly suitable for hard and brittle materials texture is ideal abrasive machining .4, green silicon carbide:The main chemical composition of SiC used in the manufacture of raw materials such as black silicon carbide plus industrial salt production are substantially the same as the reaction agent and accelerator reaction from the resistance furnace. Terms of their color is green so named for the green silicon carbide . green silicon carbide texture than the more pure black, green silicon carbide powder can be made, even higher hardness than black silicon carbide and silicon carbide which uses the same ground outside is more suitable for fine grinding of materials such as grinding thread, measuring tools, etc. in the grinding mill material is more widely used carbide, diamond products of the workpiece. Because green silicon carbide in the manufacturing cost is higher than the black silicon carbide, such as the use of raw materials is not the same on the ratio, plus a salt auxiliary materials as well as differences in processing power and so on, so green silicon carbide products cheaper than Black silicon carbide is higher. Therefore, the selection of green silicon carbide and silicon carbide in comparison, in the non-metallic and non-ferrous materials generally do not use green silicon carbide, green silicon carbide as the main choice and precision grinding carbide grinding, in belt and other coated abrasives green silicon carbide as grinding on the selection of materials for less.5, microcrystalline corundum:The main chemical components of AL2O3, used the same raw materials and corundum, only in the smelting process using rapid cooling process fine crystals obtained results. Fine crystalline corundum corundum mechanical strength than ordinary higher. Made with microcrystalline corundum abrasives commonly used for coarse grinding steel, high toughness titanium-nickel alloy steel and other difficult to grind materials, but rarely used in the manufacture of coated abrasives.

 

Developments of refractories and corundum, silicon carbide refractories application

Refractories are widely used in metallurgy, building materials, chemicals, nonferrous metals and other high-temperature industrial, which cuts the base material in many fields. Refractories and high temperature industrial interdependence, mutual promotion and common development, China's industrial economic development plays an important supporting role. Of refractory industry has made great progress, in 2010 more than 2,000 enterprises above designated size, yield 28 million tons.
Refractories industry development status of
1 position in the national economy refractories
Refractories are widely used in metallurgy, building materials, chemicals, nonferrous metals and other high-temperature industrial, which cuts the base material in many fields shared. The proportion of high-temperature industrial applications is approximately: 65% steel, building materials, 17%, 4% nonferrous metals, chemicals accounted for 4%, other 10%. Applications involving all sectors of the national economy, the industry and the refractory industry interdependence, mutual promotion and common development, no refractories, there is no high-temperature industrial. Refractory technological advances supporting high-temperature industrial development, the implementation of "energy saving, emission reduction and saving" strategy and "low carbon economy" has played a very important role in promoting.
2 of Refractories Refractories in the international market position
In the iron and steel, nonferrous metals, building materials, chemical industry, electric power and other high-temperature industrial development, driven by the rapid industrial development of refractory materials, production processes, technology, equipment levels rising, continuously improve product quality, variety increasing gradually been recognized by the international market , production and sales has for many years ranked first in the world.
Currently the variety and amount of refractory products not only meet the domestic high-temperature industrial production, development needs, and refractory products export volume increased year by year, the market throughout many countries in Southeast Asia and the Americas, European Union, Russia and other 150 countries (regions). Of refractory industry has been from small to large, from weak to strong, to become the world refractories industry, mainly producing and consuming countries.
As China's industrial structure adjustment and optimization of refractories, asset restructuring, elimination of backward production capacity of the accelerated pace of the strength of some refractory enterprises through the listing and the formation of enterprise groups in the capital and production equipment, has strong technical strength to participate in international competition in the market. The next few years, China will account for a larger refractory international market share, will become a truly world-refractory manufacturing center.
3 of refractories industry development achievements
In recent years, the rapid development of high-temperature industrial technology, driven by strong, China's refractory industry, adhere to scientific development, changing concepts, focus on independent innovation in the optimization and upgrading of industrial structure, product structure adjustment and upgrading of technical equipment as well as in the world refractory industry's competitiveness, etc. have achieved outstanding results for our steel and high-temperature industrial development has laid a solid foundation.
Optimization and upgrading of industrial structure, size and growth. Some refractory enterprises through powerful alliances, mergers and acquisitions, cross-shareholdings and other ways to strategic integration, and promote the refractory industry structure adjustment, optimization and industrial upgrading.
Product structure adjustment, independent innovation ability. In order to meet long-life steel industry blast furnaces to improve converter furnace, refining and efficient continuous casting technology, has developed a special micro-pore structure and the blast furnace process to produce ceramic cup with a slightly corundum brick, Sialon bonded corundum products, blast furnace zone drying strength corundum - nitride - silicon carbide composite castable, non-oxide refractory metal composite oxide containing blast furnace iron runner Si3N4 Si3N4 composite materials and blast furnace gunning, magnesium and calcium brick, tundish ventilation intakes, clean steel casting with carbon-free silicon and thin-slab continuous casting nozzle submerged nozzle and other new products, Baosteel, Anshan Iron and Steel, Wuhan Iron and Steel and other large enterprises to use, and achieved good results. Building materials and other industries for the service, has developed a float glass furnace oxidation no shrinkage casting and regular cast AZS series of cast products, cement kiln directly bonded magnesia chrome brick, magnesia chrome brick semi-combined, the new new dry-process cement kiln tabular alumina castable, National Science and Technology Progress Award of the aluminum reduction cell combined with a silicon nitride nitride brick refractory products, chemicals with a series of high-purity alumina refractory products and other ancillary products in the domestic large-scale enterprises with favorable results, replacing the imported products. Monolithic refractories has been widely applied trough of blast furnace, one pass more than 100,000 tons of iron. Work in the ladle lining life of up to 1000 times. Mixer working lining using all or part of the whole cast replace brick lining, the service life of up to three years. Torpedo using wet jet repair, life expectancy increased by 25% or more. In order to improve construction efficiency and avoiding extreme weather disturbances, ladle castable also adopted a work precast lining. Ladle, ladle, tundish backing by the volume density of 1.6-2.2g/cm3 high strength, low shrinkage semi lightweight castable to reduce heat loss. Large and shaped preform castable used increasingly and exported abroad, such as furnace burners, flue tiles, anchoring brick, brick blast furnace combination, etc., are used castable prefabricated parts. Corundum, silicon carbide materials for the development of these products should play a major role.
Production technology and equipment to accelerate the pace of upgrading. With the rapid development of the refractory industry, refractory production enterprises, key enterprises in particular the level of equipment is constantly upgraded.
4 Refractory Production Status
2010 refractory industry enterprises above designated size was 2,000, yield 28 million tons. Product support, variety, yield higher than the growth rate of fixed assets, the product structure was further optimized to meet the high-temperature industrial and technological progress. Industry on cost control ability level higher equipment levels have significantly improved profitability has been further improved, the industry to promote energy conservation, environmental protection, there is significant progress in the development of refractories industry as a whole more stable.
5 refractory raw resource availability
A wide variety of refractory raw materials, resources are more abundant, which magnesite, bauxite refractory raw materials and other resources called China's pillar, fire clay, silica, dolomite, magnesium olivine, serpentine, zircon and other resources widely distributed, fine texture. These refractory raw material resources for China's refractories industry, providing a reliable foundation conditions.
6 of refractories industry problems
Although our refractories industry has made great progress, but according to the concept and practice the scientific concept of development, the current situation of the development of the industry and the national economy, there are many inappropriate places, the raw material resources, product structure, technology and equipment, consumption levels, energy conservation, environmental protection and industry concentration, there are still some problems with individual products still lags far behind the developed countries.
7 the development trend of refractories
High industry in China will continue to play an important role in the national economy. National development of ten industrial revitalization plan, low carbon development planning and energy saving policies on the development of high-temperature industrial far-reaching significance. Overall control, eliminate backward production capacity, industrial restructuring, technological upgrading and industrial integration is the future direction of development of high-temperature industrial.
Energy saving and recycling economy has become China's high-temperature industrial development of the basic guiding ideology. High-temperature industrial development and direction of the change will be on the development of refractory industry have a significant impact, which will greatly facilitate future sustainable development of stable refractory industry and new technologies, new materials, new technology development and application, which is refractory industry once accelerate technological innovation, the adjustment of product structure rare opportunity for development.
Technological innovation and the development of low-carbon economy will further advance the refractories industry technology innovation, product restructuring and mergers and acquisitions, green, functionality, longevity and other advanced refractory development space and market space increases.
Development of energy efficient refractories, efficient functional refractories, refractory integrated optimization technology systems integration and engineering technology; increase the efficient use of resources and refractory low-grade resource utilization and environmental protection after use eco-refractory refractory material applications; continuously improve the application of refractory technology, give full play to the function of refractories, to achieve consumption and emissions reduction.
Refractory consumption will gradually decline, the total market demand will be maintained at a certain level, the market competition will become more intense. To adapt to the development trend of reduction, refractory enterprises must eliminate backward, the adjustment of product structure, increase the technological upgrading and enhancing service levels to enhance the core competitiveness, but will also increase market integration efforts, improve industrial concentration, and enhance international competitiveness.
Major high industry demand for refractories
Iron and steel industries. The future development of the steel industry: will continue to "control the total elimination of backwardness, mergers and acquisitions, technological innovation, optimize the layout" as the core, control capacity, elimination of backward production capacity, strengthen technological innovation, the development of new materials, iron ore trade norms order to accelerate domestic enterprises to "go out" pace. 2015, construction steel proportion will drop to about 50%, the proportion of steel manufacturing rebound; plates proportion will reach 55%, the key varieties of steel self-sufficiency rate can be increased to about 95%; total production capacity surplus will continue currently half of backward production capacity will be eliminated. Next few years, although the refractory industry will be affected by the presence of iron and steel production by pulling some room for development, but the number used in steel production will continue to decline, it is expected that by 2015, the consumption of refractories will fall 15kg / t steel or so.
Building materials industry. According to China's building materials industry over the past few years the demand for refractories and refractory own development, we can predict the next few years, the building materials industry for refractories demand growth rate will slow down, but the demand will still maintain an upward trend.
The chemical industry. The next few years, the chemical industry will remain above 7% growth, the development of the industry will present different characteristics. According to the World Refractory applications industry statistics, the proportion of the chemical industry use refractory is 4% higher than this level our country. Next few years, the chemical industry will increase total demand for refractories. Large oil refining capacity expansion device and process optimization transformation, will bring some refractory industry development space.
Non-ferrous industries. By 2015, the nonferrous metals industry will further optimize the industrial structure, quality and efficiency improved significantly, significantly enhancing the capability of technological innovation, the main technical and economic indicators have reached the world advanced level, the overall strength jumped to the forefront of the world. Overall, non-ferrous metal smelting industry, the demand for refractories refractory aggregate domestic demand accounted for about 3-5%. Next few years, high-tech, high value-added refractory products demand will increase overall demand for refractory products will continue to maintain about 5%, the growth rate is not too large. Meanwhile, with the non-ferrous metal smelting technology advances and technological progress itself refractory industry, smelting need tons of products also show a downward trend in the amount of refractory material.
Overseas markets. At present, the international refractory products increasingly competitive market, or even to low-disordered unfair competition, export refractory products falling prices. According to statistics, in recent years, ordinary refractory products in the international market prices generally fell by 10%, while the decline of some species can reach 20-30%, as well as by the pressure of RMB appreciation, domestic exports increased the difficulty of refractory products. Refractory products due to the presence of domestic GB market has not yet been fully understood, and some high-end products can not meet the foreign enterprise production technology issues, the next few years, this trend will be maintained within a certain time.
Next few years China refractories overall demand situation. As international and domestic macroeconomic situation for the better, our industry in the next few years will heat usher in a new round of development opportunities, which gives refractories industry has brought opportunities and market space. Can be predicted: the number of refractory market development space is limited, a huge space for adjustment of product structure, service mode conversion will occur, industrial layout adjustment will occur. Refractory aggregate demand will not be much increased, but there will be some increase in high-performance refractory materials, including functional, energy-saving, environment-friendly and other advanced refractories market space will be further expanded, the demand ordinary products decreased.
Basic principles guiding ideology and main objectives
Guiding ideology. To the scientific development as the theme, the main line of independent innovation in order to meet the development needs of high-temperature industrial and international market demand, focusing on promoting industrial restructuring, to create a new model of sustainable development.
Basic principles. Based on domestic resources, and actively explore overseas resources, improve the level of raw material processing equipment, process optimization, rational use of low-grade raw material resources, development of high-grade synthetic refractory raw materials characteristics, the formation of development suited to China's refractory industry, high stability of series refractory raw materials.
Main objective. 2015, achieve significant decline in ordinary products, functional, energy-saving and environment-friendly products such as the proportion of refractory advanced greatly improved to meet the high-temperature industrial and emerging industries for advanced refractory products. Improving product technology content, extend product life and reduce the consumption of refractories, refractory consumption per ton in 2015 to 15 kilograms. Focus on consumption per ton of steel mills close to the international advanced level. Improve industrial concentration, optimize the industrial structure, eliminate backward production capacity to support large enterprises with comparative advantages mergers and acquisitions, foster industrial clusters. By 2015, significantly reduce the number of enterprises to further improve the existing "small, more casual" situation, bred 2-3 home sales reached ,20-30 5-10 billion sales revenue of 10-50 million with strong competitiveness and influence of the refractories business.
Development priorities
The next few years, China's refractory industry is a breakthrough in the development of key industries and key generic technologies, development of new refractory materials, leading the industry development direction. Actively explore special functional refractories, non-oxide composite materials, energy saving refractory materials, environment-friendly refractories, ceramics and other advanced special field of refractories; to China's development of strategic emerging industries, to promote low-carbon economy and high temperature industrial advanced technology as an opportunity , speeding up China's refractories industry, industrial restructuring and industrial upgrading; rational planning, the use of advanced mining and processing technologies, promote the magnesite, bauxite-based refractory materials such as resource utilization development; comprehensively promote the industry energy conservation and clean production; committed to industry standards, and guide the healthy development of industry.
Key development areas
Iron and steel industry new technologies, new processes and major equipment of key development and application of refractories. Steel industry restructuring and technological progress and the acceleration of large-scale equipment in the steel, direct reduction, and other non-coke smelting reduction ironmaking, efficient continuous casting, thin slab casting and other aspects of the refractories industry put forward new requirements and issues . In order to meet the development needs of the steel industry, iron and steel industry to develop refractory to high-performance, long-life, functional refractories and refractory efficient application of technology-based. Focus on research and development of large-scale blast furnace refractories with a long life, clean steel smelting efficient refractories, a new generation of efficient continuous casting refractories function integration, non-refractory coke ironmaking technology key technologies and applications.
Building materials, nonferrous metals, and chemical industries key equipment and key parts of the research and application of refractories. Building materials, nonferrous metals and chemical industry is an important part of our national economy, China's current production of key equipment used in these industries and key parts of the partial refractory Compared with similar products, product quality and performance but also has some gaps , to a certain extent, affected the development of these industries. Focuses on the development of green basic refractories, advanced oxides and fused cast refractories, refractory chrome chrome or low, new non-oxide composite materials, high performance kiln, waste incinerators and ash melting furnace key refractories, foundry porous ceramic filter materials with high technology and applications.
Field of low-carbon energy efficient thermal transfer and the development and application of monolithic refractories. Improve thermal efficiency furnace, reducing energy consumption is to achieve energy saving high temperature industrial focus of development. Research and development of high-temperature insulation refractory material, as well as energy-efficient combustion technology matching, can greatly reduce the energy consumption of industrial furnaces, high temperature industrial energy saving on the whole has a decisive significance. Unshaped refractory materials plays an important role, but also the future direction of development of refractory materials, their production and construction process is simple, can be mechanized construction, environmental protection, high temperature has been widely used in industry. We should vigorously develop, promote the use of a variety of high quality and efficient monolithic refractories, and strive to 2015, the proportion of monolithic refractories around 50%. Focus on research and development of lightweight refractory porous highly fortified industrial technology, super-insulation materials industry prepared nano-technology, high-performance crystal fibers and products of advanced manufacturing technology, high-performance lightweight refractory aggregate production technology, the series monolithic insulating refractory materials, multifunctional monolithic refractories, large and shaped preform preparation techniques, stereotypes of unshaped refractory materials, flame spraying and wet jet technology.
Refractory resource utilization technology development and application. Refractory materials of low resource utilization, waste generated each year iron ore fines, super ten million tons of low-grade ore, a huge amount of revenue and expenditure refractory raw material resources is imperative. Rational use of fine ore, low grade ore is refractory industry limited resources conservation for sustainable development urgent task.
Refractory after use will generate a lot of waste refractories, refractory materials for waste treatment and recycling for environmental protection, clean production and achieving sustainable development of great significance. Focuses on the development and application of low-grade magnesite and bauxite resource utilization of industrial technology, comprehensive utilization of refractory mineral tailings key technologies, high-quality synthetic refractory raw materials, "three stone" (andalusite, sillimanite, kyanite) raw comprehensive and efficient use, recycling and refractory after use and reuse of resource integration technology.
Refractories industry standards and promotion. Existing standards of refractories, refractory industry to promote the development of technology has played an important supporting role. With technological progress, China's refractory industry standard in intellectual property protection, industry development guidance, resource sharing, enterprise participation, standards, international standards, etc., and the reality of our country is not commensurate with the scale of production of refractories, refractory standard system need further improvement to make it more scientific and reasonable. Access standards in the industry, "energy-saving and environment-friendly" standards and refractory products and other new energy standards, the technique should be followed by the development of international standards, to fully absorb the international advanced achievements of refractories, and comprehensively promote to have our intellectual property-based standard system. Focus on the refractories industry access standards (including the energy, environmental protection, scale, variety, etc.) the formulation of new refractory industry testing methods and standards development and promotion of Chinese refractories industry standard internationalization.
Corundum, silicon carbide refractories application
Reform and opening up, high-temperature industrial backward technology and equipment, refractories single species, a large proportion of ordinary refractory materials, corundum, silicon carbide materials rarely, corundum less than 10%, a silicon carbide less than 5%. Technical equipment introduction, digestion, enhance the high-temperature industrial level of technology. High-temperature industrial process equipment technology to improve and enhance the quality of quality refractories made demanding. Corundum, silicon carbide materials resistant to corrosion, slag corrosion, wear resistance, the amount of high-temperature industrial technological progress as needed, with special refractories, unshaped refractories varieties increased the dosage is gradually increased. Such as: iron and steel industry blast furnaces, the iron ditch, Mixer, ladle, continuous casting, electric stove top and other amorphous materials. Such as: cement industry kiln lining material with amorphous silicon Mo bricks. Such as: non-ferrous industrial smelting furnace nitride bonded silicon carbide bricks. Corundum, silicon carbide and other refractory materials to promote the adjustment of product structure.
Market needs, but development is limited. Corundum vigorous market demand, but its supply of raw materials was extremely restricted. Long-term over-exploitation, high alumina refractory clay depleted, if uncontrolled, refractory materials, corundum bauxite resources required, will soon dry up. Since 2010, raising the cost of production factors such as price, make corundum, silicon carbide smelting enterprises have encountered unprecedented difficulties. Currently operating at only 25% of Henan, some companies are forced to move to areas with lower tariffs. Its high cost, high prices, this situation has affected the development of the downstream industry chain.
Future development proposals backward to upgrade equipment. Refractory stable quality performance requirements, need to dump furnace, therefore, in accordance with national policies, the following ordinary corundum phase 3000 kVA and 4000 kVA smelting furnace fixed corundum smelting furnaces. Strictly control capacity expansion, not duplication. Compressed production scale, production efficiency. High alumina refractory clay is already scarce resources, have a plan to protect the refractory materials, corundum use.
High-temperature industrial development is inseparable from refractories, refractory industry's development is inseparable corundum and silicon carbide refractory raw materials!

Grinding method

The flexible abrasive polishing tools and polishing media particles or other modification of the surface of the workpiece processing. Polishing can not improve the dimensional accuracy of the workpiece or geometric shape accuracy, but to obtain a smooth surface or specular gloss for the purpose, sometimes to eliminate gloss (extinction).
Usually buff as a polishing tool. Buff general use multi canvas, felt or leather crafted stacked on both sides with a metal circular plate clamped its rim coated abrasives and grease, etc. from the powder mixture evenly polish. Polishing, buff rotating speed (peripheral speed of 20 m / sec or more) is pressed against the workpiece, the abrasive surface of the workpiece and trace rolling cutting, machining to obtain a shiny surface, generally up to the surface roughness Ra0.63 to 0.01 micron; When using non-greasy matting polishing agent, shiny surfaces can to improve the appearance of extinction.
Mass production of steel ball bearings, often using barreling approach. Rough polishing will be a lot of balls, lime and abrasives on pot-shaped drum tilted, the drum rotates, the ball and abrasive in the barrel rolling crash at random convex front surface to achieve the removal of the surface roughness is reduced purpose, can remove a margin of about 0.01 mm.
Fine polishing ball when loaded in barrels and fur pieces, available hours continuous rotation dazzling bright surface. Polishing precision line scale is machined surface immersed in, carried abrasive powder, polishing powder, polishing powder particle size W5 ~ W0.5 by the alumina powder and cerium oxide powder combined together. Uniform fine polishing using material degreased thin wood or a special felts, its trajectory uniform dense mesh, the surface roughness after polishing is less than Ra0.01 microns, the enlarged 40 times under the microscope than any surface defects. There are also other methods electrolytic polishing.

Purpose and nature of black silicon carbide quality specifications

A black silicon carbide is silicon carbide, refractory materials can be used, it can be used as the abrasive, and green silicon carbide similar are hexagonal crystals, a specific gravity of 3.20 ~ 3.25, microhardness of 2840 ~ 3320kg/mm2.
Black silicon carbide is composed of quartz sand, petroleum coke, wood and other raw materials at high temperatures in a resistance furnace smelting, its hardness between corundum and diamond, the mechanical strength is higher than corundum, brittle and sharp.
1 properties
Great hardness of silicon carbide, with excellent thermal and electrical conductivity, high temperature anti-oxidation.
2 Uses
(1) as an abrasive, can be used for abrasives, such as grinding wheel, Whetstone, grinding, sand tile etc..
(2) as a deoxidizer and high temperature metallurgical materials.
Silicon carbide has four major application areas, namely: functional ceramics, advanced refractories, abrasives and metallurgical raw materials. Currently a large number of silicon carbide coarse material has been able to supply, can not be considered high-tech products, and high-tech application of nanoscale silicon carbide powder is impossible to form a short time scale economies.
(3) high-purity single crystal, can be used for manufacturing a semiconductor, manufacturing a silicon carbide fibers.
3. Origin, exports to the country and quality specifications
(1) Place of Origin: Qinghai, Ningxia, Henan, Sichuan, Guizhou and other places.
(2) exports to country: United States, Japan, Korea, and some European countries.
(3) Specification:
① grade silicon carbide abrasive technical conditions at GB/T2480-96.
② abrasive particle size and composition according to GB/T2477-83. Abrasive grain size determination method according to GB/T2481-83.
Carbide such as silicon carbide refractory itself into the smelting industry also faces significant changes in the performance of pressure, high purity, high toughness, high density silicon carbide, it is in many performance with ordinary silicon carbide has a relatively large difference.
It is not only good toughness, bulk density, water absorption, porosity and purity silicon carbide and other indicators are normal can not be compared, is that it is most advantageous when processed into powder, chemical composition is not reduced, chemical and physical properties maintain the original features. For this reason, high-purity, high toughness, high-density silicon carbide is held in high esteem, the high-quality silicon carbide products for a variety of high-tech fields.

SiC ultra-fine grinding works

SiC ultra-fine grinding works:
Material into the grinding chamber, the spindle is rotated by the rotation of the roller swings outward centrifugal force, roller pressed on the grinding ring, shovel blade materials to the grinding roller and grinding ring, between the grinding rollers and grinding ring rolling and under pressure between the material repeatedly roll crushing, sandblasting abrasive in the grinding chamber and lead mixed into a fluidized air flow.
In the classification round lead centrifugal action of the wind and the system to achieve the thickness of separation, does not meet the size requirements of coarse crushing area to continue falling back pulverized into powder qualified grading machine for sorting, finer powder into the cyclone collector after , the centrifugal force, along the cyclone powder rotating cylinder wall is decreased, the end of the inner cone is separated, after the separation into the pulse finer powder collector, the purified gas into the atmosphere via the induced draft fan. A negative pressure state in the whole system work.
Production process: feeding → Host → grading machine → cyclone collector → → pulse collector fan.

Corundum powder processing process

Fine polishing abrasive grinding process-flow indispensable processing materials. As part of the diversity, there must be a corresponding fine polishing abrasives.
Corundum, white corundum, white corundum, with a homogeneous, suitable hardness, wear resistance, etc., use unbreakable to technical appraisal by experts, to fill the gaps, reached the international level of similar products to replace imports, with the kind polisher machines.
Corundum powder is used in ultra-fine grinding of a computer chip components, electronic communication products silicon components, rocket engine temperature component, high temperature gas turbine blade components, such ultra-fine grinding corundum powder production methods, based on aluminum hydroxide as raw material, after calcination, grinding, pickling, grading and drying to obtain, for the particle size of 40 microns or less fine powder, classified by hydraulic sedimentation method, from fine to coarse classification carried out in the first level of fine, coarse level, after that , the classification is completed until all.
Classification method in the strict control slurry concentration, settling time, while the siphon height, adding an efficient dispersant, the dispersant molecule in water between aggregated particles interspersed, including all attached to the periphery of particles of different sizes, by dispersant molecular charge repulsion, the particles can no longer get together, both to improve the accuracy of such classification, but also makes the final product can be kept loose state.

 

Five use of corundum

Corundum has the following five main scope of use
1 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 materials.
(2) 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 profile glass, washed jeans precision molds and other fields.
3 Resin Abrasives - Abrasives has the right color, hardness, toughness, suitable particle cross-section type and edge retention, resin abrasive used, the results are satisfactory.
4 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, particularly suitable for non-ferrous metal processing: oil drilling mud weighting agent .
5 corundum functional filler - mainly used for automobile brake parts, specialty tires, specialty building products in areas such as construction of motorways. Airstrip. Pier. Parking. Industrial floor. Stadium and other wear-resistant materials .

 

Corundum is abrasive blasting is the best choice

Corundum is bauxite, coke (anthracite), iron as the main raw material, and then electric arc furnace melting temperature crystallization, it has a hardness, toughness, particle Fengrui, grinding power, high temperature, high efficiency, is the quality of abrasives materials and advanced refractories. It is made with abrasive, for grinding high tensile strength of the metal can be cut, grind a variety of common steel, carbon steel, general steel, malleable, Qingdao Steel, hard Qingdao Steel, etc., can also be As advanced refractory, widely used in iron and steel, chemical and other industries abrasive blasting with high-quality corundum as raw materials using modern new unique technology is refined. Abrasive blasting abrasive short time, high efficiency, good benefits, and low prices of the product hardness, high toughness, good self-sharpening, sand consumption is low and can recycle and reuse, grinding pieces of finish is good; and chemical composition and stability, resistant, acid and alkali. The abrasive shell-shaped fracture, sharp corners, constantly smashing step in the formation of new edges and the side edge, making it superior to other abrasive grinding capacity. In particular it has a high hardness, specific gravity, chemical stability and its unique self-sharpening, etc. become sandblasting abrasive of choice; while it is sand-blasting cleaning workpiece. Workpiece material blasting purpose craft to stainless steel surface decontamination, in addition to welding slag and matte effectCorundum use1 Iron piece: to rust, decontamination, descaling, increasing the coating, the coating adhesion2 aluminum workpiece: descaling, surface hardening, light decoration effect3 copper artifacts: Go oxidation Pia light effect4 Crystal glass: frosted, engraved pattern5 Plastic products: matte effect6 denim and other special fabric: plush processing and effectsBlack corundum abrasives are high quality bauxite as main raw material, add less then a reducing agent in smelting electric arc furnace at high temperature, the color black. Hardness, toughness greater wear sharp edges and corners, and strong self-sharpening, grinding is less heat, high polished workpiece cleaning, domestic production of water purification materials, professional manufacturers, strong technical force, excellent equipment, advanced technology , there are more than ten series kind, hundreds kinds of products, the Ministry of Construction as a professional product promotion manufacturers. The products are widely used for urban water supply, drainage, metallurgy, electric power, industrial wastewater treatment and other fields.

  

Silicon carbide products using methods and protection methods

Silicon carbide products using methods:
Prohibit the use of silicon carbide products overload, if rod appearance showing blistering appearance, often stick temperature is too high or harmful substances and stick response, should seek to decrease temperature or reduction of harmful substances stick with great touch. Surveys often use the appearance (voltmeter, ammeter, thermometer, etc.) whether the normal readings, showing abnormal timely adoption of appropriate measures to find the cause. Silicon carbide devices and connection to the furnace after. It should be loose in the axial and lateral clearance can move and change, the prohibition of forced or hard metal plates mounted plug the stick force convergence, avoiding thermal expansion force after power increase and broken rods. The cold end of the fixture and stick spray aluminum end convergence to be fastened.
Silicon carbide products protection methods:
Stick in the Deposits must pay attention to moisture; rod ends are found sprayed aluminum layer deliquescence fall; should scratch sprayed aluminum disposal can also be sprayed aluminum rods wrapped layer of aluminum foil wiring segment after use. Using bolt type clamps, the need to run for some time before tightening again, to prevent loosening clamps and rods touch bad. Water vapor will promote accelerated aging silicon carbide products; if there is water in the heating process of discharge, on the need to leave the furnace vent. New furnace or kiln from lack of use, before using the oven.
Oven as much as possible the use of other sources of heat or stick with the old. There are other corrosive atmosphere furnace, in the case of promise, but also left on the furnace vent. To adhere to the furnace temperature is normal, in the process with the use of silicon carbide rod resistance value added, should be gradually progressive use of voltage, when the voltage transformer used to progress to the highest limits of silicon carbide products equipment still can not meet the pleading, you can choose to change shutdown great way to continue using wiring methods. If excessive aging should be fully shutdown using a new stick.
Silicon carbide has a brittle ceramics; transporting, unpacking, installation, replacement process to gently prohibit or mechanical strength sensational hit, to avoid breakage.