refractory types and classification

Refractories are materials designed to withstand high temperatures and harsh conditions. They are classified based on their chemical composition, physical properties, and applications. Here are some common types and classifications of refractories:

1、Based on Chemical Composition:

Acidic Refractories: These are made from silica (SiO2) or alumina (Al2O3) as the main component. They are resistant to acidic slag and are used in environments with high acidity, such as in the chemical industry.

Basic Refractories: These are composed of magnesia (MgO) or dolomite (MgO-CaO). They have high resistance to basic slags and are used in applications involving basic substances, like steelmaking.

Neutral Refractories: These are made from chromite (FeCr2O4) or carbon. They exhibit good resistance to both acidic and basic environments and are versatile in various applications.

2、Based on Physical Properties:

Dense Refractories: These have low porosity and high density, providing excellent strength and resistance to penetration by molten materials. They are suitable for areas subjected to severe wear and corrosion.

Insulating Refractories: These have low density and high porosity, which makes them effective in reducing heat transfer. They are commonly used for thermal insulation in furnaces and kilns.

Porous Refractories: These are characterized by high porosity, allowing gases or fluids to pass through them. They are used in applications requiring gas permeability or filtration.

3、Based on Manufacturing Process:

Shaped Refractories: These are pre-formed refractory products, such as bricks, tiles, and special-shaped components, manufactured by molding and firing processes. They offer structural integrity and ease of installation.

Monolithic Refractories: These are unshaped refractory materials that are applied in a plastic, semi-plastic, or dry form. They are commonly used as castables, gunning mixes, and ramming masses, providing versatility in complex shapes and high-temperature applications.

4、Based on Application:

Iron & Steel Refractories: These are specifically designed for the iron and steel industry, including blast furnaces, ladles, converters, and tundishes.

Glass Refractories: These are tailored for glass-making processes, such as glass tanks, regenerators, and furnace crowns.

Cement Refractories: These withstand the extreme conditions in cement kilns, preheaters, and cyclones.

Petrochemical Refractories: These are used in the refining and processing of petroleum, such as fluid catalytic cracking units and reformers.

Refractories play a vital role in various industries, protecting equipment, containing heat, and ensuring efficient operations in high-temperature environments. The selection of the appropriate refractory type depends on factors like temperature, chemical atmosphere, mechanical stress, and application requirements.