Classification of refractory materials
There are various ways to classify refractory materials, mainly based on their refractoriness, shape, chemical composition, chemical properties, and bulk density, as follows:
According to fire resistance, it can be divided into
1) Ordinary refractory material, with a refractoriness of 1580-1770 ℃;
2) Advanced refractory material with a refractoriness of 1770 ℃;
3) Special grade refractory material with a fire resistance of over 2000 ℃.
According to the shape of the product, it can be divided into
1) Block shaped refractory materials (also divided into standard bricks, irregular bricks, and special products);
2) Unstructured refractory materials (such as refractory concrete, refractory plastics, refractory fibers, etc.).
According to the chemical mineral composition of the material, it can be divided into
1) Silicon products
① Silicon brick, with SiO2 content not less than 93%;
② Quartz glass products with SiO2 content of over 93%.
2) Aluminum silicate products (classified based on SiO2 and Al2O3 content)
① Half silica brick, with SiO2 content greater than 65% and Al2O3 content less than 30%;
② Clay bricks containing 30%~48% Al2O3;
③ High alumina brick, containing 48% Al2O3;
④ High purity and high aluminum products, such as corundum bricks, corundum mullite bricks, etc.
3) Magnesium products
(1) Magnesia brick, with MgO content greater than 85% and CaO content less than 3.5%;
② Magnesium aluminum brick, containing MgO greater than 80% and Al2O3 5%~10%;
③ Magnesia chromium brick, with MgO content greater than 48% and Cr2O3 content greater than 8%;
④ White marble bricks with CaO content greater than 40% and MgO content greater than 30%;
⑤ Magnesia silica brick, with MgO content greater than 82%, SiO2 content greater than 11%, and CaO content not exceeding 2.5%;
⑥ Magnesia carbon brick, with MgO content greater than 70% and C content greater than I4%.
4) Chromium products, products containing approximately 30% Cr2O3.
5) Carbonaceous refractory materials, carbon with graphite content of 20%~70%, or carbon with coke content of 70%~90%.
6) Other advanced refractory materials include zirconium refractory materials (ZrO2, SiO2), carbides (zirconium, hafnium, tungsten, etc.), nitrides (titanium, zirconium, tantalum, etc.).
According to the chemical properties of refractory materials, they can be divided into
1) Acidic refractory bricks, mainly composed of SiO2, can be corroded by alkaline slag, such as silica bricks;
2) Alkaline refractory bricks, mainly composed of MgO and CaO, can be corroded by acidic slag, such as magnesia bricks;
3) Neutral refractory bricks can resist both acidic and alkaline slag erosion, such as magnesia chrome bricks.
According to the different bulk densities of refractory materials, they can be divided into
1) Heavy refractory bricks with a bulk density of 2.2-2.75g/cm3;
2) Lightweight refractory bricks with a bulk density of 0.4~1.3g/cm3;
3) Ultra lightweight bricks with a bulk density of 0.3~0.4g/cm3 can be used as insulation materials.
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