Calcined alumina SALOX® and tabular alumina ALFA TAB® are aluminium oxides, whose high melting point makes them the most frequently used oxides in the refractory industry for products such as concrete, bricks, monolithic products, insulating material and other. They can be added to these materials or these materials can be made fully of alumina.
Different specific surface areas of calcined alumina allow their use in refractory products, which meet the requirements of the broad thermostability field. The final properties of the products are further affected by the granulation of the material and the presence of agglomerates, which increase the active specific surface area. Increased chemical purity enhances resistance to thermal shocks and consequently reduces the occurrence of local ruptures.
Sintered alumina are distinguished by low open porosity, a dense structure, high thermostability, chemical inertness and the related corrosion resistance, strong firmness, high thermal conductivity and electrical resistance, abrasion resistance and resistance to thermal and mechanical shocks, low water absorption and high density. These characteristics enable the use of tabular alumina ALFA TAB® in a number of refractory products for the needs of the steel, cement, ceramic and other industries, where processes are characterised by high temperatures.
Sintered composites of aluminium and magnesium oxide – spinels are an additional element used in refractory materials. Silkem’s sintered spinel SP67, which is rich in magnesium, is used as replacement for chrome bricks in cement ovens. Spinel bricks have the same characteristics (mechanical and thermal stability), but do not contain chrome, which is an environmentally harmful element. Silkem’s spinel SP67 is also used for refractory monoliths and in various refractory plasters. Sintered spinels SP78 and SP90, which are rich in alumina, are used for refractory products in the steel industry. The added substances significantly enhance mechanical and thermal properties of the material.
Dried silicates DRYSIL® are used as highly thermostable adhesives and as binders for sand, fireclay, alumina, corundum, etc.
|Calcined Alumina||Isostatic pressed products - Refractory bricks - Monolithic refractory materials such as concrete, masses and mortars,pre-fabricated parts, - Plasticisers (plasticiser and gunning mixes)||Abrasion and corrosion resistance - Improved refractory properties - Improved mass rheology - Mechanical resistance - Lower water requirement|
|Tabular Alumina||Refractory bricks - Monolithic refractory materials such as concrete, masses and mortars,pre-fabricated parts, - Isostatic pressed products||Improved thermomechanical properties - Abrasion and corrosion resistance - Increased volume and mechanical stability - Resistance to thermal shocks|
|Sintered Spinels||Monolithic refractory materials such as concrete, masses and mortars,pre-fabricated parts, - Refractory parts of electric arc furnaces (EAF)||Improved thermomechanical properties - Resistance to thermal shocks - High thermostability - Corrosion protection,|
|Dried Silicates DRYSIL®||Thermostable adhesives and binders in refractory products||High thermostability - Excellent binding of components in refractory products|