Classification of refractory materials by refractoriness, shape, chemical composition, chemical properties, and bulk density
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Classification of refractory materials: There are various ways to classify refractory materials, with classification primarily being based on refractoriness, shape, chemical composition, chemical properties, and bulk density. Specifically: Based on refractoriness, they can be divided into 1) ordinary refractory materials, with a refractoriness of 1580–1770°C; 2) high-grade refractory materials, with a refractoriness of 1770°C; 3) ultra-high-grade refractory materials, with a refractoriness higher than 2000°C. Based on the shape of the products, they can be classified into 1) bulk refractory materials (which can further be divided into standard bricks, special-shaped bricks, and special-type products); 2) non-bulk refractory materials (such as refractory concrete, refractory plastics, refractory fibers, etc.). Based on the chemical mineral composition of the material, they can be classified as 1) siliceous products: ① silica bricks, containing no less than 93% SiO2; ② quartz glass products, with SiO2 content above 93%. 2) Aluminosilicate products (classified based on the contents of SiO2 and Al2O3): ① Semi-silica bricks, containing more than 65% SiO2 and less than 30% Al2O3; ② Clay bricks, containing 30%–48% Al2O3; ③ High-alumina bricks, containing 48% Al2O3; ④ High-purity high-alumina products, such as corundum bricks and corundum-mullite bricks. 3) Magnesium-based products: (1) Magnesia bricks, with MgO content greater than 85% and CaO content less than 3.5%; (2) Magnesia-alumina bricks, with MgO content greater than 80% and Al2O3 content ranging from 5% to 10%; (3) Magnesia-chromium bricks, with MgO content greater than 48% and Cr2O3 content greater than 8%; (4) Dolomite bricks, with CaO content greater than 40% and MgO content greater than 30%; (5) Magnesia-silica bricks, with MgO content greater than 82%, SiO2 content greater than 11%, and CaO content not exceeding 2.5%; (6) Magnesia-carbon bricks, with MgO content greater than 70% and C content greater than 14%. 4) Chromium products, products containing approximately 30% Cr2O3. 5) Carbonaceous refractory materials: carbon with a graphite content of 20%~70%, or carbon with a coke content of 70%~90%. 6) Other advanced refractory materials, including zirconium-based refractories (ZrO2, SiO2), carbides (zirconium, hafnium, tungsten, etc.), and nitrides (titanium, zirconium, tantalum, etc.). Based on the chemical properties of refractory materials, they can be classified as follows: 1) acidic refractory bricks, which consist mainly of SiO2 and can be eroded by alkaline slags, such as silica bricks; 2) alkaline refractory bricks, which are primarily composed of MgO and CaO and can be eroded by acidic slags, such as magnesia bricks; 3) neutral refractory bricks, which can resist both acidic and alkaline slag erosion, such as magnesia-chromia bricks. Based on their volume density, refractory materials can be classified as follows: 1) heavy refractory bricks, with a volume density of 2.2–2.75 g/Cm3; 2) light refractory bricks, with a volume density of 0.4–1.3 g/Cm3; 3) ultra-light bricks, with a volume density of 0.3–0.4 g/Cm3, which can be used as insulation materials.
Refractory materials can be classified according to various criteria, including refractoriness, shape, chemical composition, chemical properties, and bulk density. 1. Classification by refractoriness: – Ordinary refractory materials: with a refractoriness of 1580–1770°C – Advanced refractory materials: with a refractoriness above 1770°C – Extra-high-grade refractory materials: with a refractoriness higher than 2000°C 2. Classification by shape: – Massive refractory materials: including standard bricks, special-shaped bricks, and custom-made products – Non-massive refractory materials: such as refractory concrete, refractory plastics, and refractory fibers 3. Classification by chemical composition: – Siliceous products: such as silica bricks (SiO2 ≥ 93%), quartz glass, etc. – Aluminosilicate products: such as semi-silica bricks, clay bricks, high-alumina bricks, etc. – Magnesia-based products: such as magnesia bricks, magnesia-alumina bricks, magnesia-chromium bricks, etc. – Chromium-based products: containing about 30% Cr2O3 – Carbonaceous refractory materials: such as carbon products containing different proportions of graphite or coke – Other advanced refractory materials: such as zirconium-based materials, carbides, nitrides, etc. 4. Classification by chemical properties: – Acidic refractory bricks: primarily composed of SiO2, and prone to erosion by alkaline substances – Alkaline refractory bricks: primarily composed of MgO and CaO, and prone to erosion by acidic substances – Neutral refractory bricks: capable of resisting erosion by both acidic and alkaline substances 5. Classification by bulk density: – Heavy refractory bricks: with a bulk density of 2.2–2.75 g/cm³ – Light refractory bricks: with a bulk density of 0.4–1.3 g/cm³ – Ultra-light bricks: with a bulk density of 0.3–0.4 g/cm³, often used as insulation materials. These classifications help us choose the appropriate refractory materials for specific application requirements. .