Boehmite is a highly thermostable aluminum oxide hydroxide. Synthetic boehmites SIBOM® are formed by hydrothermal ageing of aluminum hydroxide or gibbsite. SIBOM® is a fully crystalline (99%) boehmite with low impurity levels. The small particle size and unique structure of oxide hydroxide make it useful in a wide range of industries.
Chemical structure of Boehmites
All the vertices are located on edges that are shared by several octahedra. In nature, boehmite is found in aluminum ore called bauxite. Boehmite can be represented as long chains of AlOOH with H2O groups at the ends.
Our SIBOM® range of products also includes pseudoboehmite, which has applications similar to those of boehmite. They differ in the water content of the crystal structure, as pseudoboehmite has much shorter AlOOH chains and consequently a higher number of H2O terminal groups, and water is intercalated between the octahedral layers. As a result, pseudoboehmite is a microcrystalline material with a large specific surface area and a large pore volume. It is ideal for producing activated alumina because the pore volume remains largely unchanged during calcination at temperatures up to 1000 °C.
Production of Boehmites
Aluminum oxides are becoming increasingly important as a halogen-free, environmentally friendly refractory material for polymers processed at high temperatures. Boehmites are stable at high temperatures, making them ideal for use in electrical thermo-insulators.
Our products, marketed under the name SIBOM®, comprise crystalline boehmite with different particle size distributions and chemical purity levels. All products are available in powder or liquid form as a suspension.
Depending on their purity, our SIBOM® products are divided into standard and VLS (very low sodium) categories. In terms of granulation, we offer three options: standard granules (9–15 microns), and two ground versions: MP84-2, with an average size of around 2 microns, and MP84-1, with an average size below 1 micron.
Our pseudoboehmite is marketed under the name SIBOM® P76 and is precipitated from an acidic and caustic solution of aluminum salts at a carefully regulated pH. This product is characterized by its high chemical purity, stable specific surface area and medium pore volume.
- High purity: the Al₂O₃ content typically exceeds 99%.
- High hardness: comparable to corundum (9 on the Mohs hardness scale), which makes it ideal for abrasive applications.
- Thermal stability: withstands extremely high temperatures, making it ideal for refractory materials.
- Chemical inertness: resistant to acids and bases, ensuring a long lifetime in harsh environments.
- Controlled particle size: available in different sizes for specific applications.
- Controlled specific surface area: can be adjusted to improve reactivity or inertness.
Catalysts
Boehmites SIBOM® are used as catalyst supports in fluid catalytic cracking (FCC). Microcrystalline boehmite improves the attrition resistance of catalysts and is a suitable metal neutralizer. Boehmites are also used in other catalytic processes.
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Paints and coatings
Due to their specific properties, SIBOM® boehmites are added to paints to increase their thermal stability and reduce the amount of material that needs to be applied, and at the same time increase abrasion resistance due to their hardness.
Refractory materials
Boehmites SIBOM® are used as coating additives on the contact surfaces of various foundry furnaces and equipment for moving and casting molten materials.
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Ceramics
Boehmites SIBOM® are used in advanced ceramics to reduce shrinkage, increase density and achieve whiteness of these products.
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Fire retardants
Boehmites SIBOM® are used as fire retardants in plastic products. Due to their higher thermostability, they are ideal for use in high-stress components, such as insulation for high current conductors. Their low conductivity also makes them suitable for use in printed circuit boards.
Activated alumina
Boehmite products SIBOM® can be used as a raw material for activated alumina, which is used as a drying agent for compressed air, adsorbent for various halogens or volatile organic compounds, etc.
| Type of SIBOM® Product | P84 | P84-VLS | MP84-1 | MP84-2 | MP84-2-VLS | MP84-1-VLS | MS65 | |
|---|---|---|---|---|---|---|---|---|
| AlO(OH): Boehmite | % | > 99 | > 99 | > 99 | > 99 | > 99 | > 99 | > 99 |
| Al2O3 | % | 79 – 85 | 79 – 85 | 79 – 85 | 79 – 85 | 79 – 85 | 79 – 85 | 79 – 85 |
| Na2O Total | % | 0.10 – 0.16 | 0.01 – 0.05 | 0.10 – 0.20 | 0.10 – 0.20 | 0.00 – 0.05 | 0.00 – 0.05 | 0.10 – 0.25 |
| Fe2O3 | % | 0.02 – 0.08 | 0.02 – 0.1 | 0.02 – 0.1 | 0.02 – 0.1 | 0.02 – 0.1 | 0.02 – 0.05 | 0.02 – 0.10 |
| Additive | % | – | – | 0.50 – 0.80 | ||||
| SiO2 | % | – | – | 0.05 – 0.07 | ||||
| Bulk Density (20°C) | g/l | 700 – 1100 | 700 – 1100 | 200 – 400 | 450 – 650 | 450 – 650 | 400 – 600 | 1500 – 1700 |
| Solid Content (3h/105 °C) | % | – | 60 – 63 | |||||
| Loss on ignition (1h/800°C) | % | 16 – 19 | 16 – 19 | 16 – 19 | 16 – 19 | 16 – 19 | 16 – 19 | 16 – 19 |
| Average particle size d50 | µm | 10 – 15 | 10 – 15 | 0.9 – 1.1 | 1 – 3 | 1 – 3 | 0.7 – 1.0 | 0.9 – 1.1 |
| Specific surface area (BET) | m2/g | 2 – 8 | 2 – 8 | 5 – 15 | 5 – 15 | 5 – 15 | 10 – 20 | 5 – 15 |
| Characteristics | White powder | White powder | White powder | White powder | White powder | White powder | White slurry | |