Top 10 most commonly used refractory materials for glass furnace

The rapid development of the glass industry has naturally promoted the development and technological progress of refractory materials for glass furnaces. The technological progress of the glass furnaces requires a variety of high-quality refractory materials as a guarantee condition, and the refractory bricks are required to withstand higher temperatures, more rapid temperature changes, more intense chemical erosion, and more severe stress damage. Therefore, the proper usage of refractory bricks in different parts of glass furnace is very important to the lifetime of the furnace. As a professional manufacturer of refractory materials, Zhengzhou Shennan Refractory Co., Ltd has been dedicated to develop new and high-quality refractory bricks for glass industry. The following article will give a brief introduction to the top 10 most commonly used refractory in glass furnaces.






Top 10 most commonly used refractory materials for glass furnace

Table of Contents


1. Silica brick

What is silica brick?

Silica brick is the most important and most important type of brick used in float glass melting furnaces. The SiO2 content of high-end products of silica brick is 96~98%. It is an acidic refractory material; its density is 2.35 to 2.38g/cm3, and it has high high-temperature structural strength, such as high softening temperature under load (1640~1700℃) and low creep rate, and it absorbs a small amount of alkali components Except for slight erosion, it does not reduce the structural strength of the kiln roof. The main disadvantage of silica bricks is low thermal shock resistance.

Where is the silica brick used in the glass furnace?

For large melting kilns, silica bricks are mainly used for the kiln roof of the melting part and the working part, the breast wall and the front and rear walls, the top of the regenerator and the upper partition wall of the regenerator.

What are the characteristics of silica bricks for glass kilns?

  1. The volume is stable at high temperature, and the furnace body will not change due to temperature fluctuations: the glass melting furnace can keep the furnace body from deformation at 1600°C and the structure is stable.
  2. Slight pollution to the molten glass: the main component of the silica brick is SiO2, if there is a block or surface droplets during use, it will not affect the quality of the molten glass.
  3. Chemical resistance: the upper structure of the silicon brick is corroded by the volatilized R2O gas in the glass batch, and a smooth metamorphic layer is formed on the surface, which reduces the corrosion rate and plays a protective role.
  4.  Its volume density is small: it can reduce the weight of the furnace body.



2.Clay brick 

What is clay brick? 

Clay bricks are refractory products produced with refractory clay as raw materials, and float glass melting furnaces are used more. The main components of clay bricks are 30~48% Al2O3 and 50~70% SiO2. It is an acidic refractory material. As the content of Al2O3 in the brick increases, its acidity gradually weakens. It has certain corrosion resistance to acid and poor resistance to alkaline corrosion. Therefore, clay bricks are suitable for acid kilns. Environment: Its density is 2.40 to 2.56g/cm3, and although its refractoriness is as high as 1700°C, its softening temperature under load is only about 1300°C, so it cannot bear weight and pressure when used at high temperatures. The thermal shock resistance of clay bricks is good, and the fluctuation range is large, generally greater than 10 times (1100℃/water cooling), which is related to the linear expansion coefficient of clay bricks is not too large, there is no polycrystalline transformation phenomenon and the obvious particle structure .

Where are the clay bricks mainly used in the glass furnace?

Clay bricks are mainly used in kiln parts with a working temperature of 1300℃, such as checker bricks and wall bricks in the lower part of the regenerator, flue bricks and large clay bricks at the bottom of the pool.



3.High alumina brick and sillimanite brick

What is a high alumina brick? What is sillimanite brick?

High alumina bricks are aluminum silicate refractory materials with Al2O3 content greater than 48%, collectively referred to as high alumina refractories, and the use of float glass furnaces is less; if a certain proportion of sillimanite and sillimanite are added to the ingredients of high alumina bricks Other trace elements will become sillimanite bricks.

Compared with clay bricks, high alumina bricks have the outstanding advantages of high refractoriness and high softening temperature under load. Classified by mineral composition: low mullite and mullite (Al2O3 content is 48%~71.8%); mullite-corundum and corundum-mullite (Al2O3 content is 71.8%~95%); corundum Quality (Al2O3 content is 95%~100%).


Ordinary high-alumina bricks generally refer to Al2O3 content of 48%~65%, its refractoriness ≥1790℃, load softening temperature is 1420~1500℃, and its density is 2.40 to 2.65g/cm3. Its main disadvantage is its higher creep rate and poor thermal shock resistance than clay bricks. Sillimanite bricks have improved thermal shock resistance due to the addition of a certain proportion of sillimanite to the ingredients of high alumina bricks. In particular, the high temperature creep rate of the product has been reduced, so the scope of use has been expanded.

Where are the high alumina bricks and sillimanite bricks used in the glass furnace?

High alumina bricks are mainly used for building walls in the middle of the regenerator, sillimanite bricks are mainly used for the grate of the regenerator, etc.

4. Fused zirconia corundum brick

What is fused zirconia corundum brick?

Fused zirconia corundum brick is the most important type of brick used in float glass melting furnaces.

Fused zirconium corundum brick belongs to Al2O3-ZrO2-SiO2 system (referred to as fused cast AZS brick), which is an alkaline refractory material. According to the content of ZrO2, it is divided into three levels: 33%, 36%, 41%. Corresponding to my country’s grades: AZS-33 (ER1681 in France) with a density of 3.40 to 3.6g/cm3, AZS-36 (ER1685 in France) with a density of 3.45 to 3.70g/cm3, AZS-41 (ER1711 in France) ) Its density is 3.55 to 3.80g/cm3.

Fused zirconium corundum brick has good resistance to glass liquid corrosion, and its corrosion resistance increases with the increase of ZrO2 content. Because the melting temperature of ZrO2 is as high as about 2700℃, and it has high resistance to acids, alkalis, glass liquids and other media. Therefore, the load softening temperature of the fused zirconia corundum brick is ≥1790℃, and the glass phase exudation temperature is ≥1400℃; and its resistance to temperature fluctuations at high temperatures is the best.

Where are the fused zirconia corundum bricks used in the glass furnace?

For large melting furnaces, it is mainly used for the melting part and the pool wall of the neck, the breast wall of the melting part, the paving bricks at the bottom of the pool, the whole small furnace and the key parts of the regenerator.




5. Fused corundum brick

What is fused corundum brick?

Fused corundum bricks include fused α-Al2O3 bricks, fused α-βAl2O3 bricks and β-Al2O3 bricks; among them, fused α-βAl2O3 bricks are the best brick materials used in the pool wall of the float glass melting furnace. . The content of Al2O3 in α-βAl2O3 fused brick is ≥94%, and its crystal phase structure is composed of 45~55% α-Al2O3 phase and 45~60% β-Al2O3 phase; its load softening temperature is ≥1750℃, and its density is 3.38 To 3.39g/cm3.

 α-βAl2O3 fused brick does not pollute the glass, and has good resistance to glass erosion and excellent high temperature wear resistance below 1350℃.

Where are the fused corundum bricks used in the glass furnace?

For large melting furnaces, it is mainly used for the pool wall of the working part and the side wall tiles of the runner, etc.


6. Zircon brick

What is zircon brick?

Zircon brick is a refractory product made of zircon (ZrO2- SiO2) as the main raw material; the content of ZrO2 is 64~67%. It is a neutral refractory material, and its load softening temperature is ≥1650℃. The density is 3.70 to 3.75g/cm3.

Zircon bricks have good mechanical strength, high temperature resistance, good thermal shock resistance and resistance to glass liquid corrosion.

Where are zircon bricks used in the glass furnace?

It is mainly used in the melting part of the large ballast or the partition brick between the breast wall and the large ball, the fire hole, the detection hole, etc., and the use effect is better.


 7. High-purity magnesia brick

What is high purity magnesia brick?

High-purity magnesia bricks are made by pressing and sintering high-purity fused magnesia as raw materials. The Mg O content of high-purity magnesia bricks is ≥95%. It is a magnesia refractory product directly bonded between periclase grains. High-purity magnesia brick is an alkaline refractory material, its load softening temperature is ≥1750℃, and its density reaches 3.10/cm3.

High-purity magnesia bricks have good mechanical strength, high temperature resistance, thermal shock resistance, good slag resistance, and alkali resistance. However, the hydration resistance is poor, and it is easy to hydrate and crack when exposed to water, which reduces its strength. Therefore, you must pay attention to moisture, rain and snow during storage; in addition, high-purity magnesia bricks are corroded by sulfate and SO2 at 800~1000℃ to generate sulfuric acid Magnesium melts.

Where is the high-purity magnesia brick used in the glass furnace?

It is mainly used for the upper checker brick part of the regenerator, and is now also used for bricklaying on the upper wall of the regenerator and further develops its use in the regenerator.

8. Directly combined magnesia chrome brick

What is the directly combined magnesia chrome brick?

Directly bonded magnesia chrome bricks are made by pressing and sintering high-purity fused magnesia and chromite as raw materials. Directly bonded magnesia chrome bricks MgO content: 82.61%, Cr2 O3 content: 9.5%, SiO2 content 2.02%, it is cubic magnesia There is a direct bond between the stone grains and the chromite particles. It is an alkaline refractory material, its load softening temperature is ≥1765℃, and its density reaches 3.08/cm3.

Directly bonded magnesia chrome bricks have similar properties to high-purity magnesia bricks. Compared with high-purity magnesia bricks, its alkali resistance is slightly worse, and its thermal shock resistance and resistance to sulfate and SO2 are better.

Where is the direct combined magnesia chrome brick used in the glass furnace?

Mainly used in the middle and lower checker bricks of the regenerator (mainly used in the 800~1000℃ area).

9. Lightweight refractory material

What is Lightweight refractory material?

Lightweight refractory materials are heat insulation materials. It can reduce the heat dissipation of the kiln body, save energy, and can also reduce the weight of the kiln body and reduce the cost of the kiln. Lightweight refractory materials include lightweight heat-insulating refractory bricks and aluminum silicate fibers;

Lightweight heat-insulating refractory bricks can be divided into clay, siliceous, aluminum and mullite according to the raw materials used. Aluminosilicate fibers are amorphous fibers, they include: ordinary type, use temperature 1000 ℃; high purity type, use temperature 1100 ℃; high aluminum type, use temperature 1200 ℃.

Where are the lightweight refractories used in the glass furnace?

Lightweight heat-insulating refractory bricks can be divided into clay (used for flue heat preservation, heat preservation of the lower part of the regenerator and bottom of the pool, use temperature 900~1200℃) and siliceous (used for the top of the melting part and the working part) according to the raw materials used. Dome roof and regenerator dome roof insulation, use temperature 1400~1550℃), aluminum (used for small furnace dome roof, heat storage outdoor wall and breast wall and outside of pool wall insulation, use temperature 1350~1500℃) and Mo Comes in stone (the outer wall of the heat storage outdoor wall, the breast wall and the outside of the pool wall are insulated, the use temperature is 1500~1550℃), etc.

10. Unshaped refractory materials

What is unshaped refractory material?

Unshaped refractories, also called bulk refractories, are made by mixing certain graded refractory aggregates and powdered materials with binders and admixtures; refractory materials used directly without forming and firing processes.

Unshaped refractory materials can be classified according to the refractory materials used, such as siliceous, clay, high alumina, zircon, magnesia, and thermal insulation, etc.; according to the process characteristics, they can be divided into refractory mud (for wall masonry), Ramming material (for separating layer or instead of special-shaped brick), moldable refractory (for sealing and insulating layer), pouring refractory (for sealing and polishing), etc.


Where can I purchase high-quality refractory materials?

Zhengzhou Shennan Refractory Co., Ltd. is a professional manufacturer of refractory materials. We can produce different types of high-quality refractory materials for customers. If you have any demands, please click below to contact us get a quote, thank you!

 


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