Silkem offers a wide range of products for the refractory industry. In addition to the several types of calcined alumina SALOX® and tabular alumina ALFA TAB®, the range also includes sintered spinels SP67, SP78 and SP90. Silkem also produces dried silicates under the brand DRYSIL®.
Tabular alumina, magnesium spinel, calcined alumina and reactive alumina are key materials in the refractory industry, providing high performance, durability and resistance to extreme conditions. These materials are essential for ensuring quality and effectiveness in applications involving very high temperatures and mechanical stress.
Different specific surface areas of calcined alumina enable their use for refractory products with a wide thermostability range. The final properties of products are also affected by the granulation of the material and the presence of agglomerates, which increase the active specific surface area. Increased chemical purity improves resistance to thermal shock, thereby reducing the likelihood of localized ruptures.
Tabular alumina
Tabular alumina ALFA TAB® is an extremely pure and dense material produced by sintering alumina without additives at very high temperatures. Due to its high specific density, exceptional mechanical strength and thermal shock resistance, it is widely used as a raw material in the production of refractory products such as bricks and monolithic materials.
Tabular alumina ALFA TAB® has the following advantages:
Magnesium spinel
Magnesium spinel is a compound of magnesium oxide (MgO) and aluminum oxide (Al₂O₃). This material combines the advantages of both its components, making it ideal for applications in harsh high-temperature environments, such as furnaces in the cement, glass and foundry industries.
The advantages of magnesium spinels SP67, SP78 and SP90 are their high thermal shock resistance and chemical resistance, which ensure long life in extreme temperature environments and through multiple heating cycles. Magnesium spinel is commonly used as an additive in monolithic refractory materials to enhance their strength and resistance. In addition, it helps to reduce cracking and improve the overall stability of the material in high-temperature environments.
Calcined alumina
Calcined alumina or aluminum oxide is a thermally treated material that has improved physico-chemical properties. Silkem produces calcined alumina under the brand name SALOX®. This material is widely used as a raw material in the production of ceramic and refractory materials due to its high purity and stability.
Calcined alumina SALOX® has the following advantages:
Calcined alumina is a key component in the production of refractory bricks, monoliths and cements. Its use improves the thermostability and durability of products, which is essential for many processes involving high temperatures.
Reactive alumina is a special type of calcined alumina. These finely ground aluminum oxides have a higher active surface area and are an excellent additional component in refractory bricks and monoliths as they improve the homogeneity of the structured refractory material and reduce its porosity. The advantages of using them in the matrix include improved binding between materials, which increases the curing or hardening rate, and improved mechanical and thermal properties of the material, as well as a lower process temperature required to obtain the same type of refractory product.
Reactive alumina is indispensable in the production of low cement and ultra-low cement concrete. Its use enables precision processing and improved performance of the finished products, providing significant advantages in industries that require superior performance at high temperatures.
Dried silicates DRYSIL® are used as highly thermostable adhesives and as binders for sand, fireclay, alumina, corundum, etc.
| Product | Applications | Effect |
|---|---|---|
| Tabular alumina ALFA TAB® 30 | Refractory bricks; monolithic refractory materials such as concrete, masses and mortars; pre-fabricated elements; isostatically pressed products | Improved thermomechanical properties, increased abrasion and corrosion resistance, increased volume and mechanical stability, thermal shock resistance |
| Calcined alumina SALOX® | Refractory bricks; monolithic refractory materials such as concrete, masses and mortars; pre-fabricated elements; isostatically pressed products; plasticizers (plasticizer and gunning mixes) | Improved refractory properties, improved mass rheology, corrosion and abrasion resistance, mechanical resistance, reduced water requirements |
| Sintered spinels SP76, SP78, SP90 | Refractory parts of electric arc furnaces (EAF); monolithic refractory materials such as concrete, masses and mortars | High thermostability, corrosion protection, improved thermomechanical properties, improved thermal shock resistance |
| Dried silicates DRYSIL® | Thermostable adhesives and binders in refractory products | High thermostability, excellent binding of components in refractory products |