Refractory materials are used in various fields of the national economy such as steel, non-ferrous metals, glass, cement, ceramics, petrochemicals, machinery, boilers, light industry, electric power, military industry, etc., and are essential basic materials to ensure the production operation and technological development of the above-mentioned industries. Plays an irreplaceable and important role in the development of high temperature industrial production.
Since 2001, driven by the rapid development of high-temperature industries such as steel, non-ferrous metals, petrochemicals, and building materials, the refractory industry has maintained a good growth trend and has become a major producer and exporter of refractories in the world. In 2011, China's refractory production accounted for about 65% of the world's total, and its production and sales ranked first in the world.
From 2001 to 2010, the output of refractory raw materials and products increased steadily, of which the end of the "Tenth Five-Year Plan" was about twice that of 2001; in 2010, the national output of refractory products reached 28.0806 million tons, about three times that of the end of the "Tenth Five-Year Plan". As of 2011, there were 1,917 enterprises above designated size in China's refractory industry, employing more than 300,000 people, achieving sales revenue of 337.679 billion yuan and product sales profit of 47.737 billion yuan.
However, due to the low level of disorderly mining and processing technology, the low level of comprehensive utilization of resources, and the serious waste, the above-mentioned mineral resources, especially the high-grade refractory raw material resources, have become less and less, and resource conservation and comprehensive utilization have become a top priority..
Song Zhenyu believes that the refractory industry must guide the organization of scientific mining of raw material mines, optimize and comprehensively utilize resources, especially the homogenization of ore deposits of different grades, prevent indiscriminate mining and excavation, and gradually promote more rational use of resources, so that limited resources play a maximum role and achieve sustainable development.
The development of the refractory industry is closely related to the possession of domestic mineral resources. Bauxite, magnesite and graphite are the three major refractory raw materials. China is one of the world's three major bauxite exporters, with the world's largest magnesite reserves and a major graphite exporter. Rich resources have supported China's refractory materials through a decade of rapid development.
At the same time, there are many refractory enterprises in China, and the scale, process technology, control technology, and equipment level of the enterprises are uneven. Advanced production methods and backward production methods coexist. The overall clean production level of the industry is not high, and the task of energy conservation and emission reduction is arduous.
As China accelerates the elimination of outdated and high-energy-consuming production capacity during the "Twelfth Five-Year Plan" period, the industry will focus on the development and promotion of new energy-saving furnaces and kilns, the development of comprehensive energy-saving technologies, energy management, emission control of "three wastes" and "three wastes" Recycling and utilization, etc. Committed to the recycling and reuse of post-use refractory materials, reducing solid waste emissions, improving the comprehensive utilization rate of resources, and comprehensively promoting energy conservation and emission reduction.
The "Refractory Industry Development Policy" pointed out that the unit consumption of refractory materials in China's iron and steel industry is about 25 kilograms per ton of steel, and will drop to less than 15 kilograms by 2020. In 2020, China's refractory products with longer life, more energy saving, pollution-free and functional products will be greatly improved. The products meet the needs of national economic development such as metallurgy, building materials, chemical industry and emerging industries, and improve the technical content of export products.
（Al 2O3+2R2 O 3）
|0.2MPa Load softening start temperature
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Refractory bricks for glass kilns are widely used, from low temperature to medium temperature to high temperature, and are necessary for industrial kilns to build lining structures. When we choose refractory materials, we have to consider many aspects. How to choose our suitable refractory brick products for glass kilns. First, we need to see which type of brick we need. The types of refractory bricks for glass kilns are different and have different uses. Second, we have to see which kind of furnace is used, and then look at the quality of refractory bricks for glass kilns. When determining the demand, the quality of refractory bricks reaches the standard, and then the price is compared. The following is an example of the three major float glass thermal equipment for glass production, including float glass furnace, float glass tin tank and glass annealing kiln.
Refractory Bricks for Glass Kilns During glass production, refractory bricks for glass furnaces function to melt the mixture into a glass liquid and clarify, homogenize and cool it to the temperature required for forming.
The tin bath is the key equipment for glass forming. The glass liquid with a temperature of 1050~ 1100 ° C flows into the liquid tin surface in the tin bath from the flow channel. The glass liquid is flat polished on the surface of the tin bath, and the glass ribbon of the required width and thickness is formed by mechanical drawing, edge holding and edge drawing machine control. And leave the tin bath in the process of gradually cooling to 600 ° C.
The function of the annealing kiln is to eliminate the residual stress and optical inhomogeneity of the float glass and stabilize the internal structure of the glass. The continuous glass ribbon produced from the tin tank at a temperature of about 600 ° C enters the annealing kiln through a transition roller.
These three kinds of thermal equipment all need to use refractory materials, and glass melting furnaces are often used in the following 9 kinds of refractory products:
1. Refractory bricks for glass kilns: glass kilns and silicon bricks
Silica bricks are widely used in glass kilns, and the main component is silicon dioxide (SiO2). The silica content required for silica bricks for glass melting kilns is required to be above 94%, the high service degree is about 1600~ 1650 ° C, and the density is 1.8~ 1.95g/cm3. The porosity is required to be less than 22%, and the larger the porosity, the worse the quality of the silica brick. The appearance of silica bricks is mostly white crystal, and the microscopic composition is the crystal of quartz. Because silica bricks undergo crystallization transformation and volume expansion at high temperature, especially at about 180~ 270 ° C and 573 ° C, the crystallization transformation is more intense. Adapt to the crystallization transformation of silica bricks during the roasting kiln and cold repair process, and take appropriate measures, such as elastic tensile tape, etc. Silica brick masonry should leave expansion joints.
The working temperature of silica bricks is about 200 ° C higher than that of clay bricks, but they have poor corrosion resistance to liquid glass and alkaline flying materials, so they are used to build large structures such as large concrete, parapets and small furnaces. In masonry, high-silicon refractory mud or silica brick powder and other materials close to the composition of silica bricks should be used as cementing materials.
2. Refractory bricks for glass kilns: glass kiln clay bricks
The main components of clay bricks are Al2O3 and SiO2. The Al2O3 content is between 30% and 45%, the SiO3 is between 51% and 66%, the density is 1.7~ 2.4g/cm3, and the apparent porosity is 12%~ 21%. The service temperature is 1350~ 1500 ° C. In the glass industry, clay bricks are used to build the bottom of the kiln. Walls and channels of the working part, walls of the updater, rafts, lower lattice bricks and flue ducts. As the temperature increases, the volume of the clay brick expands. When the temperature exceeds 1450 ° C, the volume will shrink.
3. Refractory bricks for glass kilns: high-alumina bricks for glass kilns
The main components of high-alumina bricks are also SiO2 and Al2O3, but Al2O3 should be greater than 46%. It is made of corundum, high bauxite or sillimanite mineral (Al2O3-SiO2). The density is 2.3~ 3.0g/cm3, the apparent porosity is about 18%~ 23%, and the high service temperature is 1500~ 1650 ℃. When the porosity of high-alumina bricks is low, the corrosion resistance is good. High-alumina bricks can be used to build cooling pool walls, updater, updater walls, etc.
4. Refractory bricks for glass kilns: mullite bricks
The main component of mullite brick is Al2O3, which is about 75%. Because it is mainly mullite crystal, it is called mullite brick. The density is 2.7-32g/cm3, the opening rate is 1% - 12%, and the high working temperature is 1500~ 1700 ° C. Sintered mullite is mainly used to build renewal walls.
Molten mullite is mainly used for laying pool walls, observation holes, wall sills, etc.
5. Refractory bricks for glass kilns: fused zirconium corundum bricks
Molten zirconium corundum bricks are also called white iron bricks. Usually, according to the content of zirconium, molten zirconium corundum bricks are divided into 33%, 36% and 41%. Zirconium corundum bricks used in the glass industry contain 50% to 70% Al2O3, 20% to 40% ZrO2, density 3.4 to 4.0g/cm3, apparent porosity 1% to 10%, high temperature about 1700 ℃, including, molten zirconium corundum bricks with 33% and 36% zirconium are used for masonry kiln wall, flame space chest wall, small furnace jet port, small furnace shovel, small furnace, tongue sputum, etc. Use% molten corundum bricks to build corners of pool walls, fluid holes and other glass to violently erode severe parts of solar eclipses. This material is a widely used molten refractory in the glass industry.
6. Refractory bricks for glass kilns: fused alumina bricks
Mainly refers to molten α, β corundum, molten β corundum cast refractory bricks, mainly composed of 92%~ 94% Al2O3 corundum crystal phase, density 2.9~ 3.05g/cm3, apparent porosity 1%~ 10%, high use, temperature is about 1700 ° C.
Molten alumina has good resistance to glass dialysis and hardly pollutes glass. It is widely used in glass walls, tank bottoms, flow channels, working section channel walls, material channel bottoms, etc. of glass melting kiln studios, and does not require refractory contamination.
7. Refractory bricks for glass kilns: quartz bricks
The main component of quartz brick is SiO2, the content is as high as 99%, the density is 1.9~ 2g/cm3, the fire resistance is 1650 ° C, the working temperature is about 1600 ° C, the acid corrosion resistance is used to build acidic boron walls, glass. Flame space thermocouple hole brick, etc
8. Refractory bricks for glass kilns: alkaline refractories
Alkaline refractories mainly refer to magnesia bricks, aluminum-magnesia bricks, magnesia-chromium bricks and magnesia-olivine bricks. Its properties are corrosion resistance to alkaline materials, and the refractory degree is 1900-2000 ° C. It is widely used in the upper wall of glass melting kiln renewers, renewal chambers, main structures and the structure of small furnaces.
9. Refractory bricks for glass kilns: glass kiln insulation bricks
The heat dissipation area of the glass furnace is large and the thermal efficiency is low. In order to save energy and reduce consumption, a large number of thermal insulation materials must be used to achieve integrated thermal insulation. In particular, the pool wall, pool bottom, concrete and updater walls, the molten part and the working part are insulated to reduce heat dissipation. Insulating bricks have large porosity and very low mass, and the density does not exceed 1.3g/cm3. Insulating bricks with large porosity have an adiabatic effect due to the poor heat transfer performance of air. Its heat transfer coefficient is 2 to 3 times lower than that of ordinary refractory materials, and the larger the porosity, the better the thermal insulation effect. There are many different types of thermal insulation bricks, such as clay thermal insulation bricks, silicon thermal insulation bricks and high aluminum thermal insulation bricks.