How to Improve the Compressive Strength of Refractory Bricks

The limit load a refractory sample can withstand per unit area is called the compressive strength of refractory bricks. It is an important basis for the selection and application of refractory bricks. It can be improved by the following ways. 

It can increase the density of refractory bricks. Only increasing the density of refractory bricks can obtain high strength sintered bricks. When the molding pressure is 2.2-2.3 MPa, the compressive strength is 13.9—15MPa. When the molding pressure is 3MPa, the compressive strength is 20MPa. 

Experiments show that, when raw materials and the brick machine are the same, the strength of refractory bricks varies with the sintering temperature. The compressive strength of refractory bricks increases with the increasing of the sintering temperature. 

Sintering temperature/℃ 800 850 900 950 1000 1050 1100

Compressive strength/MPa 5.4 8.5 12.6 15.9 17.5 20.4 20.8

 

Experiments show that, when other conditions are the same, changing the insulation time can change the compressive strength of refractory bricks. A suitable insulation time can improve the compressive strength and quality of refractory bricks.

Insulation time/h Compressive strength/MPa Water absorption % volume capacity rate% Weight loss%

0 11.6 21.61 0.88 10.93

1 14.9 20.67 0.94 10.73

3 17.9 20.80 1.46 12.79

 

Now sintered refractory bricks are generally internal burned. Practice has proved that, internal burned refractory bricks and high-temperature short-burning result in black heart, black scar, cracks, embossing, and a deceasing of compressive strength. What is more serious is the increased coal consumption and waste of energy. So, low-temperature long-burning is recommended. When the internal burning is 80%, within 650--900 ℃, the burning time should be no less than 6 hours and from 900℃ to the terminal of the burning, it is should be no less than 6 hours. So, the total time is 12 hours. 


Zhengzhou Sunrise Refractory Co., Ltd.  is a refractory supplier from China, specializing in refractory materials for glass furnaces. Our main products are as follows: fused cast AZS 33#,36#,41#, glass furnace fireclay bottom block, mullite brick, zircon brick, alumina bubble brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, sealing materials, building fireclay, etc.