How Are Refractory Materials Classified

Refractory materials are generally classified into five types based on the chemical-mineral composition. 

1) Aluminum Silicate Refractory

Aluminum silicate refractories include fire clay brick (Al2O3 30%-48%), high alumina brick (Al2O3>48%) and semi-silica brick (Al2O3<30%, SiO2>65%). 

2) Silica Refractory

Silica refractories include silica brick(SiO2≥93%) and fused silica brick (SiO2>99%). 

3) Magnesia Refractory

Magnesia refractories include magnesia brick (MgO>85%), magnesia alumina brick (MgO≥80%, Al2O3 5%-10%), magnesia chrome brick (MgO≥48%, Cr2O3≥12%), Magnesia Olivine Brick (MgO 35%-55%) and magnesium dolomite brick (MgO>30%, CaO>40%). 

4) Carbon Refractory

Carbon refractories include carbon brick (C 70%-90%), graphite products (graphite>30%) and SiC products. 

5) Special Refractory

Special refractories include high-purity oxide products, carbide products, nitride products, boride products and metal-ceramic composite materials as well as monolithic materials and insulation materials. 

 

Refractory brick can be divided into standard brick, common brick, shaped brick and special shaped brick according to the complexity of its shape. 

 

Standard brick, also called straight-shaped brick, is a type of rectangular brick with a standard size of 230mm×114mm×65mm. 

 

Common brick is a type of brick with a dimensions ratio (ratio of minimum and maximum size) within 1: 4 and without concave corners, perforations or grooves, including 2-8kg fire clay brick, 2-6kg silica brick, 2-10kg high alumina brick and 4-10kg magnesia brick or magnesia alumina brick. 

 

Shaped brick, based on its chemical composition, can be categorized into fire clay and high alumina shaped brick, silica shaped brick and magnesia and magnesia alumina brick. Fire clay and high alumina shaped brick includes 21-15kg fire clay brick and 2-18kg high alumina brick with a dimension ratio within 1:6, no more than 2 concave corners, one 50︒-75︒ acute angle and no more than 4 grooves. Silica shaped brick includes 2-12kg silica brick with a dimension ratio within 1:5, no more than 1 concave corner, one 50︒-75︒ acute angle and no more than 2 grooves. Magnesia and magnesia alumina bricks that do not belong to common bricks are all categorized into shaped bricks. 

 

Special shaped bricks, based on its chemical composition, can be categorized into fire clay and high alumina special shaped brick and silica special shaped brick. Fire clay and high alumina special shaped brick includes 1.5-30kg fire clay brick and 1.5-35kg high alumina brick with a dimension ratio within 1:8, no more than 4 concave corners including arch-shaped concave corners, one 50︒-30︒acute angle, no more than 8 grooves and no more than one hole. Silica special shaped brick includes 1.5-25kg silica brick with a dimension ratio within 1:6, no more than 4 concave corners including arch-shaped concave corners, one 50︒-30︒acute angle, no more than 4 grooves and no more than one hole.