When people talk about refractory fire brick, many people think it is related to fire fighting in high building construction and used for fire retardant materials in life. This perception, which is only taken literally, treats this product as normal fireproof bricks to build a tall building or a house in normal life. In fact, this understanding is very one-sided and even incorrect. Let me give you an exact definition of refractory fire brick.
Refractory fire bricks are are made of refractory clay or other refractory raw materials. The fire brick is mainly used for smelting furnace, and can withstand high temperatures of 1280℃-1770℃.Refractory fire brick can be made into different shapes and sizes following the kiln designing. According to the preparation process, it can be divided into firing brick, non-firing brick, electrofusion brick (fused cast brick), heat insulation brick. It can be used as high-temperature building material and structural materials for industrial kilns and various thermal engineering equipment,and can withstand various physical and chemical changes and mechanical effects at high temperatures.
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According to the different chemical components of firebricks, they can be divided into five categories, namely: silica-alumina fire brick, alkaline fire brick, carbon-containing bricks, zirconium-containing fire bricks, and heat-insulating fire bricks. Any kiln is not only built with one kind of firebrick, it needs a combination of different high heat refractory bricks. The components of these five types of firebricks are introduced in detail below.
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This type of firebricks are based on the phase diagram of the AL2O3-SiO2 binary system as the basic theory, mainly includes the following.
It is mainly used for building coke ovens, but also used in top arch position or load-bearing parts of furnaces for several industries of glass, ceramics, carbon calciner. They are also used in the hot blast stove as high temperature load-bearing parts but should not be used in the hot work equipment below 600 ℃ and under condition of temperature fluctuations.
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This kind of fire bricks are mainly composed of mullite (25% to 50%), glass phase (25% to 60%) and square quartz and quartz (up to 30%). Fireclay bricks are commonly used in blast furnaces,hot blast furnaces, heating kilns, power boilers, lime kilns, rotary kilns,ceramics and refractory brick firing kilns.
High alumina fire brick has the mineral composition of corundum, mullite and glass phase.It can be divided into several grades according to the AL2O3 content. The raw materials aremainly high alumina bauxite and natural ores of sillimanite type. It can also be mixed with electro fused corundum, sintered alumina, synthetic mullite, and clinker calcined with alumina and clay in different proportions. It is mostly produced by sintering method. These fire bricks and high alumina mortar are widely used in the steel industry, non-ferrous metal industry and other industries.
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Corundum brick refers to the brick with the AL2O3 content more than 90%. With corundum phase as the main phase, this kind of bricks can be divided into sintered corundum brick and electrofusion corundum brick.
Alkaline refractory kiln bricks refer to bricks using alkaline oxides such as MgO and CaO as the main components of refractory products, the main varieties are the following.
It refers to dense fire brick with magnesite as raw material, periclase as the main crystal phase, and MgO content above 80%-85%. Depending on the chemical composition and use,there are Martin sand, ordinary metallurgical magnesia, ordinary magnesia brick, magnesia silica brick, magnesia alumina brick, magnesia calcium brick,magnesia carbon brick and other varieties. As an important high-grade refractory brick, it is mainly used in open hearth, oxygen converter, electric furnace and non-ferrous metal smelting.
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This fire brick is produced with dolomite as the main raw material. It is widely used in alkaline converters,and can also be used as the outer lining of some refining ladle.
As dense bricks,carbon containing bricks are made of carbon or carbon compounds. Containing different forms of carbon as the main component, it is mainly divided into the following categories
Carbon bricks are widely used in masonry blast furnace bottom, kiln hearth, hearth and lower part of the kiln body.
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This fire bricks can be used for ladle lining, nozzle, plug, blast kiln bottom and hearth,tapping trough, converter and electric kiln tapping, etc.
Zircon dense bricks are widely used in the metallurgical industry to build degassing steel ladle lining, stainless-steel making ladle lining, and continuous casting steel ladle inside lining.
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These kiln bricks are also known as fused zirconium corundum dense firebricks. With the development of the glass industry, Fused cast AZS bricks have become a necessary refractory material for the key parts of the glass kiln.
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It refers to firebrick with high porosity, low bulk density and low thermal conductivity. Thermal insulation refractories are also called lightweight refractories. It includes the following categories.
High-aluminum heat-insulating lightweight refractory fire bricks can be used to build heat-insulating layers and parts that are not corroded and scoured by strong and high-temperature molten materials.
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(B) Clay-Based Heat Insulating firebrick
According to the Chinese standard (GB3994-1983),standard clay bricks are divided into 10 grades NG-1.5, NG-1.3a,NG-1.3b, NG-1.0, NG-0.9, NG-0.8, NG-0.7, NG-0.6, NG-0.5, NG-0.4 based on its bulk density.
Zhengzhou Shennan Refractory Co.,ltd(SNR) is a professional manufacturer of the sintered refractory bricks for more than 30 years and provided different refractory materials for customers of cement industry, Iron and steel industry, and glass industry. SNR refractory products have been exported to more than 35 countries and won a good reputation. Any question about refractory fire brick, please contact us.
