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The Difference Between Corundum Brick and Corundum Mullite Brick

2023-08-31 by globalrefractory

Both corundum bricks and corundum mullite bricks are high-grade refractory materials with high-temperature compressive strength and excellent wear resistance. There are differences between the two in terms of composition and physical properties. Rongsheng Refractory Material Manufacturer is a refractory material manufacturer with rich production and sales experience. We provide refractory services globally. Product quality is reliable, after-sales service is guaranteed.

Corundum Brick and Corundum Mullite Brick

Corundum brick. Corundum bricks are mainly made of high-purity raw materials such as alumina and corundum and usually do not contain impurities such as free silicates. Among them, corundum is a mineral with high hardness and high density, which can form a hard crystal structure in the sintering process. As a result, the corundum brick has high compressive strength, wear resistance, and other properties.

Corundum mullite bricks. Corundum mullite bricks are mainly composed of corundum, mullite, alumina, and other raw materials. Among them, the functions of corundum and alumina are similar to those of corundum bricks, while mullite has a high melting point and refractory performance, and is a common component of high-quality refractory materials. The production process of corundum mullite bricks is more complicated than that of corundum bricks and requires multiple processes. From raw material preparation, and mixing to molding, sintering, etc. The whole process needs to control factors such as temperature, time, and pressure.

Physical properties of corundum bricks and corundum mullite bricks

density. The density of corundum bricks is usually between 3.6-3.8g/cm³, while the density of corundum-mullite bricks is between 2.9-3.2g/cm³. Therefore, under the same volume, the corundum brick is heavier than the corundum mullite brick.

compressive strength. In high-temperature environments, both corundum brick and corundum mullite brick have high compressive strength. But in general, the compressive strength of corundum bricks is higher than that of corundum mullite bricks. Specifically, at a temperature of 1600°C, the compressive strength of corundum bricks can reach more than 120MPa, while the compressive strength of corundum-mullite bricks is around 80-90MPa.

abrasion resistance. Since the corundum brick contains a large amount of corundum crystals, its wear resistance is relatively excellent. Corundum bricks are widely used in the manufacture of wear-resistant lining boards, ceramic tiles, and other products. The corundum mullite brick also has high wear resistance, and due to the participation of mullite. Making it more corrosion-resistant, it can be used to make products such as acid and alkali-resistant bricks.

fire resistance. Corundum bricks and corundum mullite bricks have excellent refractory properties and are not prone to structural changes and shrinkage in high-temperature environments. The operating temperature range of the two is also very wide and can be used for a long time in a high-temperature environment of 1400°C-1800°C. Has extremely high stability and mechanical strength.

Thermal expansion coefficient. The coefficient of thermal expansion of corundum bricks and corundum mullite bricks is relatively small, especially at high temperatures. The thermal expansion coefficient of corundum bricks at 900°C is about 6.0×10^-6/°C, while that of corundum mullite bricks is about 7.0×10^-6/°C. Therefore, on some occasions that need to withstand high-temperature expansion stress, corundum bricks, and corundum mullite bricks are more suitable for use.

Application field of corundum brick and corundum mullite brick

Application fields of corundum bricks. Corundum bricks are widely used in various high-temperature industrial fields, such as metallurgy, building materials, chemicals, electric power, medicine, and other industries. Corundum bricks can be used to manufacture high-temperature furnaces, refractory linings, casting molds, electrolytic cell linings, etc. Its excellent properties make it an ideal refractory material.

Application fields of corundum mullite bricks. Corundum mullite bricks are widely used in the chemical industry, metallurgy, ceramics, and other fields. Among them, corundum mullite bricks have better acid corrosion resistance, especially in the steelmaking process, corundum mullite bricks can be used to make acid-resistant reactors. At the same time, corundum mullite bricks can also be used in high-temperature occasions such as making aluminum electrolytic cells.

RS Global Refractory Manufacturer

Both corundum bricks and corundum mullite bricks are high-grade refractory materials with excellent physical properties, but there are differences in their composition and physical properties. Corundum bricks are mainly composed of alumina and corundum and have high compressive strength and wear resistance. The corundum mullite brick is composed of corundum, mullite, alumina, and other raw materials, and its acid corrosion resistance is better. Both materials have a wide range of application fields, and it is necessary to choose the appropriate material according to specific production needs and environmental requirements. To purchase high-quality refractory brick products, please contact us. Get free samples, solutions, and quotes.

Comparison of the Performance of Corundum Bricks and Chrome Corundum Bricks in Applications

2022-12-06 by globalrefractory

Corundum bricks are refractory bricks with an alumina content greater than 90%. Corundum bricks are divided into sintered corundum bricks and fused corundum bricks. The chrome corundum brick is a refractory brick with Cr2O3 added to the corundum. Chrome corundum bricks are divided into two types: fused cast chrome corundum bricks and sintered chrome corundum bricks.

Corundum bricks are used in industrial furnaces under high temperatures, high pressure, and other environments. Corundum bricks and chrome corundum bricks have similarities and differences.

Fire resistance

Adding Cr2O3 to the corundum material will not only reduce the fire resistance of the material but will improve the fire resistance of the material. The refractoriness of chrome corundum bricks is greater than 1790°C and the softening temperature under load is greater than 1700°C, both of which are better than corundum bricks.

Compressive strength

The normal temperature compressive strength of corundum bricks is 70~100MPa. The room temperature compressive strength of high-performance chrome corundum bricks is generally greater than 150MPa, which is significantly higher than that of corundum bricks. During the firing process of corundum bricks and chrome corundum bricks, Al2O3-Cr2O3 solid solutions are formed between the particles, between the particles and the fine powder, and between the fine powder and the fine powder. The solid solution connects the particles and fine powder together like a bridge so that the strength of the material is greatly improved.

Thermal shock stability

Adding Cr2O3 to corundum, when the Cr2O3 content is 10%-66%, the thermal shock stability of the material decreases with the increase of the Cr2O3 content. That is, chromium corundum bricks with low Cr2O3 content have better thermal shock stability than chrome corundum bricks with high Cr2O3 content. The Cr2O3 content of high-performance chromium corundum bricks is between 12% and 20%, and its thermal shock stability is improved compared with corundum bricks. Especially the AKZ chrome corundum brick produced by adding a small number of additives that cause phase change has better thermal shock stability.

Resistance to slag erosion

Corundum bricks are severely eroded by slag, and the slag will completely penetrate into the brick and penetrate to the surface along the pores inside the brick, and the brick will turn brown with almost no slag remaining. Chrome corundum bricks are hardly corroded by molten slag, there is no obvious chemical reaction between the slag and the brick surface, the boundary between the inner hole edge and the slag is clear, and the slag rarely penetrates into the brick. Only a 5-10 mm thick metamorphic layer is formed around the brick hole, and a large amount of slag remains in the crucible hole. Chromium corundum bricks have better resistance to chemical erosion and permeability of gasifier slag than corundum bricks, and their resistance to structural spalling is also superior to corundum bricks.

Application

Chrome corundum bricks are used as glass kiln lining, brushed glass flow hole cover, and plate brick, and are used for molten iron pretreatment devices, garbage incinerators, gasifier backing, etc. Corundum bricks are used in various high-temperature kiln linings and kiln furniture such as cracking and reforming furnaces in the petrochemical and chemical fertilizer industries, steelmaking furnaces in the metallurgical industry, and blast furnaces. Among them, chrome corundum bricks are more resistant to high temperatures and corrosion than corundum bricks, which can meet the common needs of industrial kilns.

What is Alumina Silicate Refractory Brick?

2022-09-26 by globalrefractory

Alumina Silicate Refractory Bricks, for those who do not understand the refractory industry, maybe this is a kind of refractory bricks containing aluminum and silicon. But for people in the refractory industry, there is no such name, only aluminum-silicon-based refractory bricks. So, what are Alumina Silicate Refractory Bricks? What is Alumina-Silicate Refractory Brick? First of all, let’s take a look at the definition, what does aluminum-silicon refractory brick mean?

Silicon Bricks - Rongsheng Refractory Bricks — Silicon Bricks

Alumina Silicate Refractory Bricks, also known as aluminum-silicon refractory bricks, are refractory products containing Al2O3 and SiO2 and are a series of aluminum-silicon refractory bricks. Aluminum-silicon-based refractory bricks have a wide range of applications and occupy a very important position in the refractory application industry. Its usage accounts for more than 40% of the entire refractory products.

By definition, Alumina Silicate Refractory Bricks are a series that includes multiple types of refractory bricks. Below we categorize them to give you a deeper understanding.

High Alumina Refractory Bricks - Rongsheng Company — High Alumina Refractory Bricks

Aluminum-silicon-based refractory bricks are classified in the order of increasing composition from SiO2 content to Al2O3 content.

(1) Silica brick: SiO2 content ≥93%;
(2) Semi-silica brick: Al2O3 content is 15%-30%;
(3) Clay brick: Al2O3 content is 30%-48%;
(4) High alumina brick: Al2O3 content ≥48%;
(5) Mullite brick: Al2O3 content ≥72%, SiO2 content ≥28%;
(6) Corundum brick: Al2O3 content ≥90%.

It can be seen from the classification that silica bricks, clay bricks, and high alumina bricks are all commonly used refractory bricks for kilns. Often used for masonry kiln working layer, permanent layer, etc. Below we introduce the application of aluminum-silicon-based refractory bricks.

Alumina Silicate Refractory Bricks and Their Application Range

Silica brick. Partition wall and lining of coke oven carbonization chamber and combustion chamber, the lining of hot blast stove roof and regenerator, small electric furnace roof masonry, glass kiln roof, acid steel furnace, and firing kiln dome.
Semi-silica brick. Mainly used in coke ovens, acidified iron furnaces, metallurgical furnace flues, ladle linings, molten iron tanks, glass kilns, heating furnaces, hot blast stove tops, boiler combustion chambers, etc. Semi-silica bricks are not only used in these parts but can also be used as raw materials to make refractory materials with better quality, such as flow steel bricks.
Clay bricks. Clay bricks are used to build heating and heat treatment furnaces, flues, open hearth regenerator checker bricks, and the bottom of regenerator walls. The lining of air ducts and gas ducts, dust collectors of iron furnaces, and linings of flues. The drying zone and preheating zone of the rotary kiln are lined. It is also a commonly used refractory material in furnaces such as boilers, lime kilns, glass kilns, and ceramic kilns.
High alumina brick. Masonry blast furnace, hot blast stove, ladle, rotary kiln lining, and other metallurgical kilns. High-alumina bricks can also be used as lattice bricks on hot blast stoves to stack regenerators.
Mullite bricks. Mullite bricks are commonly used in hot blast furnaces for ironmaking at high temperatures above 1200°C, parts of torpedo tankers impacted by molten iron, and slag lines. Furnace roof of steelmaking electric arc furnace, ceramic industrial furnace, regenerator arch, the superstructure of glass melting furnace, cement, rotary kiln lining, etc.
Corundum brick. Used in blast furnaces, hot blast furnaces, and refining furnaces in the metallurgical industry. Second-stage furnaces, gasification furnaces, gas-making furnaces, cracking furnaces, and various high-temperature heating furnaces in ceramics, building materials, and other industries in the petrochemical industry.

It can be seen from the above list that aluminum-silicon-based refractory bricks are widely used in various kilns. One kind of refractory brick can be used for the refractory lining of many kinds of thermal furnace equipment, and one kind of kiln needs many kinds of refractory bricks. Therefore, when users communicate with refractory manufacturers about aluminum-silicon-based refractory bricks, they should determine the location of use and the use environment, so as to choose the correct Alumina Silicate Refractory Bricks.

Good quality refractory bricks are the basic conditions for increasing the service life of the kiln lining. Choosing a strong refractory manufacturer not only saves procurement costs, but also ensures the quality of refractory materials, reduces the number of furnace shutdowns and repairs, and briefly increases production costs. Contact Rongsheng refractory manufacturers to get the most competitive price of Alumina Silicate Refractory Bricks.