Products Description
Magnesia-aluminum spinel has high bulk density, high mineral phase content, good grain development, uniform structure, and stable quality. Magnesia-aluminum spinel also has good resistance to erosion and corrosion, strong spalling resistance, good slag resistance, abrasion resistance, excellent thermal shock stability, high-temperature resistance, and other performance characteristics. It is an ideal raw material for the production of refractory products such as magnesia-aluminum spinel bricks for the high-temperature zone of cement rotary kilns, ladle lining bricks, ladle castables, and more. Magnesia-aluminum spinel is widely used in refractories, iron and steel smelting, cement rotary kilns, and glass industry kilns.
Advantage
High melting point: The melting point reaches 2135 ℃, allowing the structure to remain stable in high-temperature environments.
Excellent slag erosion resistance: Good resistance to both alkaline slags (such as steel slag in steel smelting) and acidic media (such as glass slag).
Good thermal shock stability: A low coefficient of thermal expansion (about 7.6×10⁻⁶/°C) enables it to withstand sudden temperature changes without cracking.
Strong chemical stability: It is not prone to chemical reactions with metal or slag and has a long service life.
Chromium-free and environmentally friendly: Compared with traditional magnesium-chromium spinel, magnesia-aluminum spinel does not contain hexavalent chromium, meeting environmental protection requirements.
Raw Materials
Magnesia-aluminum spinel is an oxide mineral with a cubic crystal system and the chemical formula MgAl₂O₄. Its theoretical composition is:
Magnesium oxide (MgO): 28.2%
Aluminum oxide (Al₂O₃): 71.8%
Natural spinel reserves are relatively small, and the raw material used for industrial purposes is mainly produced through artificial synthesis. It has a high melting point (2135 °C), a low coefficient of thermal expansion (7.6 × 10⁻⁶/°C), and excellent resistance to erosion.
Physical And Chemical Specifications
Sintered Magnesium-Aluminum Spinel
| Item | Al₂O₃ % | MgO % | SiO₂ % | Fe₂O₃ % | Bulk Density (g/cm³) | Refractoriness (℃) |
|---|---|---|---|---|---|---|
| Index | 60 - 78 | 20 - 35 | ≤4.5 | ≤0.7 - 2 | 2.8 - 3.3 | ≥1850 |
Fused Magnesium-Aluminum Spinel
| Specification and Performance | MA-70 | MA-75 | ||||
| Sand | Powder | Sand | Powder | |||
| ＞0.1mm | ≤0.1mm | ＞0.1mm | ≤0.1mm | |||
| Chemical Composition | Al₂O₃ | 67 - 75% | 67 - 75% | 74 - 78% | 74 - 78% | |
| SiO₂ | ≤0.4% | 0.4% | 0.6% | 0.6% | ||
| Fe₂O₃ | ≤0.5% | 0.5% | 0.25% | 0.3% | ||
| MgO | 23 - 31% | 23 - 31% | 21 - 25% | 21 - 25% | ||
| CaO | ≤0.65% | 0.65% | 0.4% | 0.4% | ||
| Physical Performance | Magnetic Substance | ≤0.05% | 0.1% | 0.05% | 0.1% | |
| Apparent Porosity | ≤5% | ≤3% | ||||
| Bulk Density | ≥3.3g/cm³ | ≤3.3% | ||||
Process
Sintered Aluminum-Magnesium Spinel Production Process:
Sintered aluminum-magnesium spinel is produced using high-quality bauxite with Al₂O₃ content of 76% or higher and active magnesium oxide with MgO content of 95% or above. After undergoing a multi-stage homogenization process, the raw materials are sintered at temperatures above 1800 ℃ in an ultra-high-temperature tunnel kiln. The process involves continuous ceramization, with controlled feed rates and balanced temperature distribution throughout the kiln. This results in highly uniform products with crystal sizes ranging from 30 to 80 μm and low porosity (approximately 3%).
Production Process of Electrofused Aluminum-Magnesium Spinel:
Electrofused aluminum-magnesium spinel is produced by high-temperature melting in a large electric arc furnace, using high-purity light-burned activated magnesium oxide powder (≥96%) and high-quality industrial alumina powder (≥98.5%). It is a high-quality refractory raw material used to manufacture high-strength, high-performance refractory products with excellent thermal stability. It is also an ideal raw material for the metallurgy and building materials industries.
For Applications
Sintered Aluminum-Magnesium Spinel Usage:
Sintered aluminum-magnesium spinel is an ideal raw material for the production of refractory products such as magnesia-aluminum spinel bricks for the high-temperature zone of cement rotary kilns, ladle lining bricks, ladle castables, and more. When used in cement rotary kilns, it not only avoids chromium pollution but also provides excellent resistance to spalling.
When used in ladle castables, sintered aluminum-magnesium spinel significantly improves the erosion resistance of the steel plate lining, making it widely used in refractories for steelmaking. The production of high-quality pre-synthesized spinel offers a new raw material for both shaped and unshaped high-purity refractory products.
Electrofused Aluminum-Magnesium Spinel Usage:
Electrofused aluminum-magnesium spinel is widely used in steelmaking electric furnace roofs, high-performance castables, continuous casting slide gates, sliding nozzles, ladle lining bricks, and flat furnace roof bricks.
Aluminum-magnesium spinel products have excellent high-temperature mechanical properties and serve as key raw materials for large cement kilns, medium-sized cement rotary kilns (especially for excessive zone lining bricks), refractory castables, and medium- to high-temperature kiln furniture.
Aluminum-magnesium spinel is extensively used in refractories for iron and steel smelting, cement rotary kilns, and glass industry kilns.
Applications
1. Iron and Steel Industry
Application parts: Steel furnace lining, ladle lining, intermediate ladle, RH refining furnace, etc.
Typical products: Magnesia-aluminum spinel bricks, magnesia-aluminum spinel castables.
Advantages:
Resistant to erosion by FeO, CaO, and other oxides in steel slag, reducing furnace lining loss.
Can replace some magnesia-carbon bricks in ladles, improving thermal shock resistance and extending service life.
Spinel coating materials for intermediate ladles can reduce inclusions in molten steel and improve its purity.
2. Cement Industry
Application parts: Cement kiln firing zone, transition zone lining.
Typical products: Magnesia-aluminum spinel refractory bricks, magnesia-aluminum spinel–corundum castables.
Advantages:
Resistant to erosion by CaO, SiO₂, and alkali metals (K, Na) in cement clinker.
Able to withstand frequent temperature fluctuations in the kiln (around 1450 ℃), reducing spalling damage.
3. Glass Industry
Application parts: Regenerator chamber, feeder port, and breast wall of glass kilns.
Typical products: Magnesia-aluminum spinel refractory bricks, electrofused magnesia-aluminum spinel products.
Advantages:
Resistant to erosion by Na₂O, SiO₂, and other acidic media in glass slag.
Maintains a dense structure at high temperatures, reducing glass liquid infiltration and volatile corrosion.
4. Non-Ferrous Metal Smelting
Application parts: Aluminum electrolyzer lining, copper and nickel smelting furnace lining.
Typical products: Magnesia-aluminum spinel–carbon composite bricks, spinel ramming materials.
Advantages:
Resistant to erosion by molten aluminum and electrolytes (e.g., cryolite).
Resistant to corrosion by sulfur-containing slag in copper-nickel smelting, helping maintain furnace lining integrity.
5. Other High-Temperature Fields
Application parts: Ceramic sintering furnaces, waste incinerators, high-temperature test furnaces, etc.
Typical products: Spinel refractory coatings, high-temperature kiln furniture.
Advantages:
Excellent high-temperature oxidation resistance and resistance to furnace gas corrosion.
Suitable for complex, high-temperature operating conditions.
By choosing ZINFON as your supplier, you can access high-quality refractory bricks, a wide range of other refractory materials, and comprehensive support. Contact ZINFON Refractories immediately to discuss your specific requirements and obtain customized solutions!
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