What Are The Types of Refractory Bricks

Refractory is defined as the quality of a material to retain its strength at higher temperature. These materials are used inside the furnaces, kilns incinerators and reactors. These materials should be chemically and physically stable at higher temperature. They must be resistant to the thermal shock. They should be chemically inert and have specific values of thermal conductivity and coefficient of thermal expansion.

The basic requirement of a refractory brick is to withstand heat. It also should not conduct heat to save energy. In case it conducts heat, a separate insulation refractory material should be used to ensure the safety of those who are working close to the oven or the furnace that is lined with refractory bricks. The refractory brick should also be strong. In any case, firebricks should not spall under rapid temperature change, and their strength should hold up well during rapid temperature changes. It should also resist contamination of the material with which it comes into contact.

Properties of different types of refractory brick may differ. These differences are caused by the changing composition of the clay used in the manufacture of refractory brick.

According to the chemical composition, refractories can be classified into three types: acidic refractories, basic refractories and neutral refractories. Each has its pros and cons and applications.

Acid refractories are those which are not attacked or affected by acidic materials, but easily attacked by alkalis (basic slags). These are used in areas where slag and atmosphere are acidic. Acid refractories include substances such as zirconia (ZrO2), alumina (Al2O3), silica (SiO2) and fire clay brick refractories.

Neutral refractories are chemically stable to both acids and bases and are used in areas where slag and atmosphere are either acidic or basic. They are used in areas where slags and atmosphere are either acidic or basic. The common substances of neutral refractories are Carbon, Chromites (Cr2O3) and Alumina (Al2O3).

Basic refractories are those which are attacked by acid slags but stable to alkaline slags. These are used on areas where slags and atmosphere are basic. Since they do not react with alkaline slags, these refractories are of considerable importance for furnace linings where the environment is alkaline; for example non-ferrous metallurgical operations. The common substances of basic refractories includes magnesia (MgO), dolomite and chrome-magnesia.

On the basis of the manufacturing methods, refractories can also divided into dry press process, fused cast, sand molded, formed and un-formed. They can also be categorized into shaped refractories and unshaped refractories based on the physical form.

Numerous companies manufacture refractory brick in a range of shapes, sizes, and styles, and it can be ordered directly through manufacturers or through companies which supply materials to people who work with high heat processing of materials. You must choose the right type of refractory bricks for your specific need. If you use the wrong type, you might not get the results you expect.

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