Refractory balls are commonly used heat storage or support materials in industrial high temperature equipment. Their classification is mainly based on material composition and performance characteristics. The following are common classifications and their brief introduction:
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1. Alumina refractory balls
Ingredients: Mainly alumina (Al₂O₃), the content is usually between 48% and 99%.
Features:
– Ordinary high-alumina balls (Al₂O₃ 48%~75%): high temperature resistance (1600~1750℃), good thermal shock resistance, and moderate cost.
– Corundum balls (Al₂O₃ ≥90%): high hardness, strong corrosion resistance, temperature resistance can reach more than 1800℃, but the cost is relatively high.
Application: high temperature environments such as blast furnaces, hot blast furnaces, and ceramic kilns.
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2. Silica refractory balls
Ingredients: mainly silicon dioxide (SiO₂) (≥93%), such as quartz refractory balls.
Features:
– Resistant to acidic environments, but easily reacts with alkaline substances at high temperatures.
– Temperature resistance of about 1600~1700℃, with a low thermal expansion coefficient.
Application: Acidic atmosphere environments such as glass kilns and coke ovens.
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3. Magnesium refractory balls
Ingredients: Mainly magnesium oxide (MgO), the content can reach more than 90%.
Features:
– Resistant to alkaline slag erosion, high high temperature strength (temperature resistance 1600~1800℃).
– But poor thermal shock resistance, easy to absorb water.
Application: Alkaline high temperature environment such as steelmaking electric furnace and converter.
Refractory Balls in Cement Manufacturing
4. Zirconium refractory balls
Ingredients: Contains zirconium oxide (ZrO₂, usually 20%~95%), often compounded with alumina or silica.
Features:
– Excellent thermal shock resistance, strong corrosion resistance, temperature resistance up to 2000℃.
– High cost, mostly used in extreme environments.
Applications: Glass melting furnace, metallurgical special furnace, aerospace field.
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5. Silicon carbide refractory ball
Ingredients: Mainly silicon carbide (SiC), content 70%~99%.
Features:
– Good thermal conductivity, excellent wear resistance, anti-oxidation (temperature resistance 1400~1600℃).
– May oxidize at high temperature, need to be matched with anti-oxidation coating.
Application: Chemical reactors, ceramic roller kilns and other scenes requiring high thermal conductivity.
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6. Composite refractory balls
Common types: aluminosilicate (Al₂O₃+SiO₂), magnesium-aluminum spinel (MgO+Al₂O₃), etc.
Features:
– Balance performance by adjusting the composition ratio, such as aluminosilicate balls can adapt to different temperatures (1200~1600℃).
– Spinel has strong resistance to thermal shock and slag erosion.
Application: Cement rotary kiln, hot blast furnace heat storage body.
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7. Lightweight refractory balls
Composition: porous structure, usually made of alumina, mullite or floating beads.
Features:
– Low density (0.8~1.5 g/cm³), low thermal conductivity, used for insulation layer.
– Low mechanical strength, temperature resistance generally does not exceed 1400℃.
Application: Insulation layer of industrial furnaces.
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Selection suggestions:
*Temperature and atmosphere: Choose magnesium for high temperature alkaline environment, choose silicon for acidic environment, and choose corundum or zirconium for extreme temperature.
*Economical efficiency: Silicon carbide and zirconium are expensive and need to be weighed according to the budget.
*Functional requirements: High aluminum or composite materials are preferred for heat storage, silicon carbide is selected for wear resistance, and lightweight materials are used for heat insulation.