Corundum refractory is a refractory material with excellent properties, mainly composed of alumina (Al2O3). Alumina is a compound with a high melting point of up to 2072, so corundum refractories have extremely high refractory and slag resistance. Corundum refractories are widely used in metallurgy, building materials, chemical and other industries, and are important materials in the field of high-temperature industry.
The characteristics of corundum refractories are as follows:
High melting point: Alumina has a melting point of up to 2072, so corundum refractories also have a very high melting point and can be used at extremely high temperatures, making them suitable for high-temperature industrial applications.
High hardness: Corundum refractory materials have a very high hardness, with a hardness of 9 on the Mohs scale, second only to diamond. This gives corundum refractories excellent performance in terms of wear and impact, and can withstand high-velocity flowing materials and high pressures at high temperatures.
Slag resistance: Corundum refractory materials have good slag resistance and can resist the erosion of various slags. This is because alumina is chemically stable and does not react chemically with slag easily.
Low coefficient of thermal expansion: Corundum refractory material has a low coefficient of thermal expansion, which makes it less variable in volume when used at high temperatures, which is conducive to maintaining the stability of the masonry.
Good thermal shock resistance: Corundum refractory material has good thermal shock resistance, even in the case of rapid temperature changes, it can maintain stable performance and is not easy to break.
Good abrasion resistance: Due to the high hardness of corundum refractory material, it has good wear resistance and can be used for a long time under high-speed flowing materials and high pressure at high temperatures.
Good corrosion resistance: corundum refractory has good corrosion resistance, can resist the erosion of various acidic and alkaline substances, and is suitable for chemical and other industries.
Good insulation: Corundum refractory has good insulation and can be used as an insulating material for electrical equipment.
The main types of corundum refractories are sintered corundum bricks, fused corundum bricks, cast corundum bricks, etc. Sintered corundum brick is a refractory material made by mixing alumina powder with other additives and sintering at high temperature. Fused corundum brick is a refractory material made by melting alumina powder in an electric arc furnace and pouring it into a mold for cooling and solidification. Cast corundum brick is a refractory material made by mixing alumina powder with a binder, pouring and molding and undergoing high temperature treatment.
Corundum refractories are widely used in metallurgy, building materials, chemical and other industries. In the metallurgical industry, corundum refractories are mainly used in key parts of high-temperature equipment such as blast furnaces, converters, and electric furnaces, such as furnace bottoms, furnace walls, furnace tops, etc. In the building materials industry, corundum refractories are mainly used for the masonry of high-temperature equipment such as glass kilns and cement kilns. In the chemical industry, corundum refractories are mainly used in high-temperature equipment and pipelines in petrochemical and inorganic chemical fields.
In short, corundum refractories have the characteristics of high melting point, high hardness, slag resistance, low thermal expansion coefficient, good thermal shock resistance, wear resistance, corrosion resistance and insulation, making them important materials in the field of high-temperature industry. With the development of science and technology and the growing demand for high-temperature industry, the research and application of corundum refractories will receive wider attention and development.
Corundum refractories refer to products with an Al2O3 content greater than 90%, also known as alumina refractory products. Corundum is very hard (on the Mohs scale) and has a high melting point. These are closely related to the firmness of the Al-0 bond in the structure. Therefore, A-Al2O3 is the main phase constituting high-temperature refractories and high-temperature electrical insulating materials.
Corundum refractory.
For the refractory industry, corundum is an artificial material made by mining furnace with bauxite as the main raw material, which can be used as abrasives and refractories. The higher purity is white corundum, and the brown one containing a small amount of impurities is brown corundum.
What are the characteristics of corundum refractories?
1. High strength and wear resistance;
2. Resistance to erosion and penetration of acid slag: the main crystal phase of all kinds of corundum is -Al2O3, which has good resistance to the erosion and penetration of acid slag. The slag produced in the ironmaking process is generally acidic slag with a high SiO2 content and a low CAO content. In the steelmaking and ironmaking industry, Al2O3-based refractories are commonly used as linings, such as high-alumina bricks for blast furnace bodies, Al2O3-SiC-C refractories (castables and ramming materials) for tap trenches, gun mud (Al2O3-SiO2-SiC-C), Al2O3-SiC-C refractories (castables and refractory bricks) for molten iron ladles and torpedo tanks, etc
3. Diversity of materials and properties: The main crystal phase of corundum is -Al2O3, which can be combined with many oxide and non-oxide phases, which improves some of its own properties, such as thermal shock resistance, slag (acidic or alkaline) erosion resistance, etc.
Corundum refractories are mainly divided into two categories: shaped products and unshaped products. The stereotyped products mainly include: 1. Corundum refractory products: alumina content is more than 98%, self-binding solid phase sintering high-purity corundum products, the binding phase is mainly corundum, and a small amount of mullite, etc., which are mainly used in petrochemical industry gasifiers, carbon black reaction furnaces, gas furnaces, ammonia decomposition furnaces, two-stage conversion furnaces, high-temperature furnaces in the refractory ceramics industry, blast furnaces in the metallurgical industry, etc.
Corundum-mullite products: made of fused white corundum, tabular corundum, fused mullite and other raw materials, through batching, mixing, high-pressure molding, and firing in a high-temperature kiln. The main crystal phase of the product is corundum, and the binding phase is mullite. It is mainly used in the ceramic industry of high-temperature firing kiln and its push plate, bearing plate and other kiln furniture.
Corundum has good stability against the action of acids, alkaline slags, metals and glass melts. It can be used in an oxidizing atmosphere at high temperatures or in a reducing atmosphere, and can receive good results. The basic raw material of corundum products is fused corundum or sintered corundum. In order to improve some properties of products, some manufacturers often add some mineral raw materials to corundum materials to form composite materials, such as zirconium corundum bricks, chrome corundum bricks, titanium corundum bricks, etc., to improve the performance of products.