Several types of refractory bricks
Silica bricks, referring to refractory bricks containing more than 93% SiO2, are the main types of acidic refractory bricks. They are primarily used for constructing coke ovens and are also applied to the arches and other load-bearing sections of various glass, ceramic, carbon sintering furnaces, and thermal kilns for refractory bricks. They are also used in the high-temperature load-bearing sections of hot blast furnaces but are not suitable for thermal equipment with temperatures below 600℃ and significant temperature fluctuations.
Clay bricks, primarily composed of mullite (25%～50%), glass phase (25%～60%), and feldspar and quartz (up to 30%), are usually made from hard clay as the raw material. The clay is pre-fired to form熟料, then mixed with soft clay and shaped by semi-dry or plastic methods at temperatures ranging from 1300 to 1400°C to produce clay bricks. Small amounts of water glass, cement, and other binders can also be added to create unbaked products and amorphous materials. They are commonly used as refractory bricks in blast furnaces, hot blast stoves, heating furnaces, power boilers, lime kilns, rotary kilns, ceramic kilns, and refractory brick firing kilns.
(3) High-alumina refractory bricks, composed of corundum, mullite, and glassy phases. The content of these minerals depends on the AL2O3/SiO2 ratio and the type and quantity of impurities, and the refractory bricks can be graded based on the AL2O3 content. The raw materials include high-alumina bauxite and natural ore of sillimanite type, as well as added electric fused corundum, sintered alumina, synthetic mullite, and clinker produced by firing alumina and clay in different proportions. It is mostly produced by the sintering method. However, the products also include cast bricks, sintered grain bricks, unburned bricks, and不定形refractory bricks. High-alumina refractory bricks are widely used in the iron and steel industry, non-ferrous metal industry, and other industries.
(4) Corundum refractory bricks, also known as corundum bricks, are refractory bricks containing not less than 90% Al2O3, primarily composed of corundum. They can be divided into sintered corundum bricks and electric fused corundum bricks.
