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Straight Fireclay Bricks

Fireclay bricks are mainly made from chamotte, being high-pressure pressed and sintered in high temperatures. The main minerals compositions are mullite phases.

Product Description


Fireclay bricks, also known as fireclay refractory bricks, are a special type of brick made of refractory clay with good resistance to high temperatures and are used in all parts of furnace lining for middle and small capacity blast furnaces because of their excellent physical and chemical properties in high temperature. These bricks are manufactured in a similar way to ordinary bricks, except that during combustion - the refractory bricks are exposed to very high temperatures.

Refractory clay is used to make refractory bricks and is usually found under coal seams. Refractory clay contains two main components, silica and alumina, with the percentage of silica ranging from 60% to 70% and the percentage of alumina ranging from 25% to 35%.
Refractory clays also contain some other components such as calcium, magnesium, iron, potassium and titanium oxides. However, in the case of high-quality refractory clays, the percentage of components other than silica and alumina does not exceed 5%.








Al2O3 % min




Fe2O3 % max




Refractoriness ℃min




Linear change on reheating % (1400℃, 2h)

+0.1~ -0.4

Apparent porosity % max


Cold crushing strength Mpa min




Bulk Density, g/cm3 min





Fire-resistant clay can be classified according to its fire resistance:

Low-strength clay bricks

Low-strength clay bricks are mainly used in fireplaces and chimneys, and also as backing bricks for bricks with higher refractoriness.

SiO 2 content 60 % -70 %
Al 2 O 3 content 23 % -33%
Other content 6 % -10 %
Working temperature 1500 ° C - 1590 ° C

Medium-sized clay bricks

Medium-sized clay bricks are suitable for applications under moderately severe conditions. They are mainly used as back-up linings, but also for low-temperature ceramic kilns and chimneys.

SiO 2 content 60-70%
Al 2 O 3 content 26%-36%
Other content 5% - 9%
Operating temperature 1630 °C - 1690 °C

High Strength Clay Bricks

High-strength refractory clay bricks are used in a wide range of applications, such as boilers, ceramic kilns, chimneys and support linings. They have good resistance to thermal shock, so refractory bricks are more economical for long-term furnace linings.

SiO 2 content 55% - 60%
Al 2 O 3 content 35%-40%
Other content 5% - 9%
Operating temperature 1690 °C - 1740 °C

Super Refractory Clay Bricks

These bricks have good strength, refractoriness, volumetric stability at high temperatures, and excellent resistance to cracking or spalling during rapid temperature changes.

SiO 2 content 49%-53%
Al 2 O 3 content 40%-44%
Other content 5% - 7%
Operating temperature 1740 °C - 1760 °C


Characteristics of Fireclay bricks

They are yellowish-white or white in color.

They are available in different sizes ranging from 9 X 4.5 X 2.5 inches to 9 X 2.75 X 2.25 inches.

An ordinary refractory brick weighs about 30 to 35 N.

The compressive strength of refractory bricks is 200 to 220 Kg/cm 2.

Water absorption varies from 5% to 10%.

They have good chemical resistance.


Types of Fireclay Bricks

1. Acid refractory bricks

Acid refractory bricks, also known as acid-resistant bricks are especially used to resist the acidic effects of chemicals or weather.

In general, ordinary refractory bricks made of natural refractory clay are as good as acid-resistant bricks, but if higher acid resistance is required, additional silica can be added to the refractory clay at up to 97% of its composition. For bonding purposes, lime can be added at 1% to 2%. Acid bricks burn for a long time at high temperatures.

2. Basic refractory bricks

They have good corrosion and chemical resistance. They contain a high amount of magnesium oxide, where lime is also used as a binding material. The different basic refractory bricks available are magnesium bricks, magnesium carbon bricks, magnesium chrome bricks, etc.

3. Neutral refractory bricks

These are good for the both acidic and alkaline lining. They have good resistance to acidic fumes and corrosive properties. Neutral brick has two types, namely high alumina brick and chrome iron brick.

High alumina bricks contain large amounts of alumina, while chromite bricks contain varying proportions of chromium, iron oxide, silica, bauxite and iron ore.


Uses of Fireclay bricks

These are used for lining the inner surfaces of kilns, furnaces, chimneys, etc.

To construct refractory structures, thereby reducing structural damage to fire incidents.

For lining wood-burning ovens.

As insulation for furnaces and baking ovens because of their low thermal conductivity.


Learn More

How to Choose Refractory Bricks?

Refractory Shapes Selection Guide

Refractory Bricks Selection Guide

The Benefits of Using Refractory Bricks

What Are Refractory Bricks And What Are They Used For?

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