What is corundum refractory materials ?

Corundum refractory refers to products with Al2O3 content greater than 90%, also known as alumina refractory products. Corundum is very hard (Mohs hardness scale) and has a high melting point. These are closely related to the firmness of Al in the structure. Therefore, a-Al2O3 is the main phase that constitutes high-temperature refractories and high-temperature electrical insulating materials.

For the refractory industry, corundum is a man-made material with bauxite as the main raw material, which is smelted in mining furnaces, and can be used as abrasives and refractories. White corundum with higher purity is called white corundum, and brown corundum with a small amount of impurities is called brown corundum.

What are the characteristics of corundum refractories?

1. High strength and good wear resistance;

2. Resistance to erosion and penetration of acid slag: The main crystal phase of various corundum is α-Al2O3, which has good resistance to erosion and penetration of acid slag. The slag produced in the ironmaking process is generally acid slag with high SiO2 content The CaO content is relatively low. In the steelmaking and ironmaking industries, Al2O3-based refractories are generally used as linings, such as high-alumina bricks in the blast furnace body, and Al2O3-SiC-C refractories in the tapping trench (castables and ramming materials). Al2O3-SiC-C refractories (castables and refractory bricks) for ladle and torpedo tanks, etc.;

3. Diversity of materials and properties: The main crystal phase of corundum is α-Al2O3, which can be compounded with many oxides and non-oxide phases, improving some of its own properties, such as thermal shock resistance, slag resistance (acidic or alkaline) ) aggressiveness, etc.


Corundum refractories are mainly divided into two categories: shaped products and unshaped products. The main shaped products are: corundum refractory products: alumina content is more than 98%, self-bonding solid-phase sintered high-purity corundum products, the bonding phase is mainly corundum, and a small amount of mullite, etc., mainly used in petrochemical industrial gasifiers , carbon black reaction furnace, gas making furnace, ammonia decomposition furnace, two-stage reformer, high temperature in refractory ceramics industry, ultra-high temperature kiln, blast furnace in 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 combined phase is mullite. It is mainly used in high-temperature firing kilns in the ceramic industry, as well as kiln furniture such as push plates and setter plates.

Corundum has good stability against the action of acid, alkaline slag, metal and glass melts. It can be used in an oxidizing atmosphere at high temperature or in a reducing atmosphere, and good results can be obtained. The basic raw material of corundum products is fused corundum or sintered corundum. In order to improve certain 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.

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