Fire clay brick is cheap and durable. It can be used for fire protection, thermal insulation, sound insulation and moisture absorption. Therefore, it is widely used in industrial production. The scrap bricks can be reused as aggregate.

When purchasing fire clay bricks, some professional knowledge is needed and some principles should be followed.

1) Take your need into account, such as specifications and materials.

2) Select appropriate manufacturers. Shop around and capare the price before you buy. Also pay attention to the credibility of manufacturers, after sales service, product quality and service attitude.

3) After selecting a manufaturer, give a visit to the factory to understand the strength of manufacturers, scale, production qualification, production capacity and evaluation on the product from other customers.

4) Pay attention to the proper use of fire clay brick in the production and the implementation of safety measures so as to make full use of fire clay brick, reduce unnecessary losses, extend the service life ansd reduce the cost.

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1) fused cast AZS 33# block is used in the sidewall in contact with glass liquid. In the upper part of the sidewall, WS AZS 44# block is the best choice.

2) PT fused cast AZS is enough in the upper part of the glass furnace.

3) In the insulated bottom, fused cast AZS WS 33# is suitable as the paving block and can be used with AZS ramming mass during the construction.

4) PT AZS 33# block made by the reducing method is used in the sidewall, flat arch and oblique arch of the small furnace.

5) PT α—β fused cast alumina block is generally used in the sidewall of the refining zone, while WSα—β fused cast alumina block is used in the bottom. However, fused cast alumina block is expensive, so 33# AZS block is used as an alternative.

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China Metallurgical standard (YB / T 5107-1993) classifies the hot stove fire clay brick into RN-42、RN-40 and RN-36 3 according to the physical and chemical parameters.

There are the following provisions for the physical and chemical parameters and the allowable size deviation.

1) If the width is not more than 0.25mm, no limit to the length;

2) If the width is between 0.26-0.5mm, length should be no more than 30mm;

3) If the width is more than 0.5mm, not allowed.

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The SiO2 content in the silica brick used in the glass furnaces should be controlled. And it should be mainly composed of cristobalite. For large glass furnaces and oxy-fuel glass furnaces, refractory materials with high purity, good creep resistance and good corrosion resistance are used.

Since the advent of brick, there are three types of brick. The first is the common silica brick. the second is high quality silica brick. the third category is improved high quality silica brick.

With the development of glass mleting technology, silica bricks with better performance are required.

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In the top part of the checker work, the temperature is high, which can reach up to 1400-1500℃. It is subjected to the most severe erosion by alkali vapor and dust. Rebonded fused magnesia brick is used here. Since rebonded fused magnesia brick contains less silicate phase, periclase crystals are fully developed and are directly bonded, which delays and deters the growing speed of the periclase crystals under the effect of alkali vapor and cracking and pulverizing of bricks.

In the upper part of the checker work, the temperature is 1100-1400℃. Rebonded magnesia brick 95 is used.

In the middle part of the checker work, the temperature is 800-1100℃, within which alkali metal sulfate is condensed and magnesium and calcium checker work severely eroded by Na2O and SO3. It is accompanied with large expansion of bricks and badly damaged. Therefore, the site should not use magnesia brick but direct bonded magnesia chrome brick, magnesia zirconia brick, synthetic magnesia olivine brick and magnesia alumina spinel brick.

In the lower part of the checker work, the temperature is low here and the corrosion is not quite severe. However, it is close to the flue and directly affected by cold air, so it should have good thermal shock resistance and low prices. low porosity fire clay brick is used here.

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Fire clay brick can be used in the metallurgical industry. Fire clay materials including shaped refractory materials and unshaped refractory materials acount for about 70% of the total refractory materials. Hard clay is used to produce refractory materials for theblast frunace, hot stove, ladle lining brick and plug brick.

High-alumina clay is used to produce alumina bricks for electric furnaces and blast furnaces, high aluminum lining brick and high alumina refractory mud. Hard clay and high alumina clay are often calcined into clinker at high temperature (1400 - 1800℃).

Refractory clay also has important roles in the grinding industry, chemical industry and ceramics industry. High-alumina clay can be made into abrasive materials by melting in an electric arc furnace. Fused corundum abrasive material is currently the most widely used an abrasive material. It acounts for 2/3 of the total abrasive materials.

High alumina clay can be used to produce a variety of aluminum compounds such as aluminum sulfate, aluminum hydroxide, aluminum chloride, aluminum potassium sulfate and other chemical products. In the ceramic industry, hard clay and semi-hard clay can be used to manufacture household porcelain, construction porcelain and industrial porcelain.

In the construction materials industry, refractory clay can be used to produce high alumina bricks, phosphate high alumina refractory bricks and high alumina fused cast bricks. High-alumina clay can be made into aluminum-containing cement by calcining and then mixing with limestone. This quick-setting cement has strogn heat and corrosion resistance.

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Magnesia brick is composed of 80-90% periclase and 8%-20% other mineral phase including magnesium ferrite (MgO·Fe2O3), forsterite (2MgO · SiO2) and Calcium and magnesium olive stone (CaO·MgO·SiO2). Silicate glass contains about 3-5% magnesium, calcium and iron. These silicates may contain tricalcium silicate (3CaO · SiO2), magnesium rhodonite (3CaO · MgO · 2SiO2), calcium and magnesium olivine and forsterite, dicalcium silicate (2CaO · SiO2).

Magnesia brick has good thermal conductivity, good thermal expansion, good corrosion resistance to alkali molten slags and bad corrosion resistance to acid molten slags. Due to the low-melting silicate cements surrounded periclase, the beginning point of the softening temperature under load is not too high, but the collapse temperature is close to the beginning point. Its refractoriness is over 2000℃, but it does not make sense in the actual use. Bad thermal shock stability is one of the main reasons for the destruction.

In the storage and transport, special attention should be paid to moisture-proof to avoid burst after affected with damp.

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During the use, some parts of the glass furnace are required to have good thermal shock resistance. Since the thermal shock stability of the dense zircon brick is bad, it reduces the service life of glass furnaces and increases the repair cost of glass furnaces.

Zircon can improve the properties of dense zircon brick. The dense zircon brick is made of zircon powder by adding high pure industrial zirconia, fused stabilized zirconia and desilicated zirconia. After Formulating according to the amount of the added zirconia, wet-mixing, spray granulation, isostatic pressing and sintering at 1530 ℃ and 12h insulation, 69% dense zircon brick is made.

Research about these three different samples of zirconia on the apparent porosity, bulk density, firing shrinkage and thermal shock stability and a scanning electron microscope (SEM) on the microstructure and fracture surface samples are carried out.

The results showed that: compared to 65 dense zircon brick without ZrO2 added, the samples with ZrO2 added have higher apparent porosity, bulk density, firing shrinkage and thermal shock stability.

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The main raw material is refractory clay. Clay is an earthy mineral. It can form plastic mud pie when mixed with water and maintain the shape after drying. It has rock-like hardness after fired at high temperature.

Additionally, the clay contains a certain amount of impurities such as quartz, mica, pyrite, feldspar and organic substances. The impurities, especially iron, can reduce the quality of clay and are harmful to the fire clay bricks.

Alkalis such as Na2O and K2O exist as mica. It can improve the sintering properties of clay and form dense products after sintered. It should be fewer than 2%.

The content of CaO is generally under 11.5% and distributed evenly. So, it will not affect the refractory properties of raw materials.

There is a certain amount of TiO2 in the bond clay. It exists as diamond. When it is less than 1%, it has no big effect on the quality of bond clay. In the chemical analysis, its content is not tested alone but counted in the content of A1203 + TiO2.

When the impurities in the clay exceed 6%, the refractoriness of clay will decease and cannot be used as the raw materials. The content of organic substances in the clay is fluctuated greatly, up to 5%.

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Fused cast AZS containing 33% ZrO2 is called 33# fused cast AZS; fused cast AZS containing 36% ZrO2 is called 36# fused cast AZS; fused cast AZS containing 41% ZrO2 is called 41# fused cast AZS.

Fused cast AZS is mainly composed of baddeleyite and corundum and their eutectic crystals. High viscosity glass phase is filled in the gaps of crystals. The crystals is directly precipitated from the molten liquid and well developed. So, it has large crystal particles and stable crystal phase. Except the voids, it has compact structure and better density than the common sintered bricks. The pores are mainly closed pores and the crystals are intertwined each other, so it has good mechanical properties and wear resistance. The impurities are difficult to invade the bricks. Therefore, this refractory brick has good corrosion resistance. besides, the transformation of ZrO2 at 900~1150℃ when heating or cooling may cause irregular deformation.

Fused cast AZS block can be used in areas in direct contact with molten metals and molten slags. It is the essential material used in the key areas that suffer from severe corrosion.

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Insulation bricks always have thermal conductivity between 0.2-0.4 w/m.k (350±25℃), while refractory bricks have thermal conductivity above 1.0w/m.k(350±25℃). So, insulation bricks have better insulation performance than refractory bricks. the refractoriness of insulation bricks is usually under 1400 degree, while that of refractory bricks is above 1400 degree. insulation bricks are generally lightweight materials with a density between 0.8-1.0g/cm3, while that of refractory bricks is above 2.0g/cm3.

Refractory bricks have better mechanical strength, long service life and better chemical stability. They do not react with batch materials. They have better high temperature performance and can withstand high temperature up to 1900℃.

Refractory bricks and insulation bricksa are quite different. Their applications and functions are quite different. It is important to select the right materials according to the actual conditions.

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For most thermal equipment, in order to save energy and improve the working conditions, insulation is necessary. However, for some equipment, insulation is not necessary, given the pros and cons of insulation. Therefore, the actual conditions and the properties of insulation bricks should be taken into consideration when selecting the right insulation bricks.

The insulation bricks can be divided into the following types:
1) Fire clay insulation brick GB/T 3994-2005
2) High alumina insulation brick
3) Mulite insulation brick

The principles for selecting insulation bricks include:
1) It should not affect the service life of the entire refractory masonry;
2) For continuously working high temperature furnaces, generally large area insulation is reasonable and can reduce the heat loss. However, for some special areas such as the open hearth roof, insulation may reduce the service life. For periodically working furnaces, regenerative heat loss is the main factor of heat loss. Insulation may increase the temperature of masonry and increase regenerative heat loss. So, whether periodically working furnaces should be insulated is determined after calculating the heat storage and heat loss.
3) Since the insulation bricks have high porosity, they cannot withstand too much load and should not directly contact the molten metals, molten slags and high-temperature dust.
4) Insulation bricks have low strength. The brick joints and expansion joints should be properly disposed avoid the damage caused by volume expansion. Insulating firebrick should not be subjected to intense mechanical vibration, shock and friction;
5) Since insulation bricks have big reheating linear shrinkage, the maximum working temperature should be 100℃ less than the firing temperature.

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Refractories used in the glass furnace are required to withstand higher temperature, sharper temperature changes, more serious chemical corrosion and severer stress damage. The common refractories used in the glass furnace are as followings:

1) Fused cast AZS and fused cast high zircon block
For fused cast AZS block, it is important to improve its corrosion resistance and wear resistance. Besides the oxidizing melting method, reducing the carbon content to 0.005 and improving the exudation temperature of glass phase to 1450℃, the casting method and annealing method are also improved to improve the quality and properties of fused cast AZS.
Fused cast high zircon block with more than 90% ZrO2 has excellent thermal shock resistance and low potential of pollution to glass.

2) Chrome brick
Dense chrome bricks made by isostatic pressing are used in the walls, throat and other severely corroded areas in the E or C glass furnaces. Its service life can be as long as 6-7 years. Cr2O3 are added into fused cast AZS block to make fused cast AZSC block (Al2O3-ZrO2-SiO2-Cr2O3). At high temperature, Cr2O3 can from solid solution with Al2O3. Since Cr2O3 has a high melting point, it can improve the viscosity of glass phase and the exudation temperature of glass phase and improve the corrosion resistance to glass.

3) Basic brick
High pure direct bond basic bricks fired at 1800℃ are widely used in the walls of regerators and crown.

4) Olivine magnesia brick
Since olivine bonding phase has high corrosion resistance, increasing the olivine content in the bonding phase of magnesia can greatly improve the corrosion resistance of magnesia brick. Olivine magnesia brick is cheap and widely used in the middle part of the checker work.

5) Celsian olivine brick
Olivine has good corrosion resistance but insufficient thermal shock resistance. Celsian can significantly improve the thermal shock resistance. Celsian is formed in the firing process, and exists only in the binding matrix phase. Celsian can resist the corrosion of alkali and sulphate.

6) Monolithic materials
The application of monolithic materials in the glass industry can greatly reduce the joints of furnace structure and the cold repair time.

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Zircon materials have been more widely used in the glass industry, metallurgical industry, cement industry, ceramics industry and refractory industry, due to high melting temperature, good chemical stability, good thermal shock, and good resistance to molten metals, slags or glass liquid.

Zircon materials are mainly used in the melting zone, superstructure, sidewall and throat. Zircon refractory materials mainly include dense zircon brick, fused cast AZS block, fused cast zircon mullite brick and rebounded AZS brick.

Zircon materials have a wide application in the metallurgical industry. According to the material, zircon materials can be divided into zircon brick, zirconite bricks, alumina zircon carbon products, zircon carbon products, zirconic acid calcium products, zirconium diboride products and zirconium oxide modified refractories.

Zirconite products have good high temperature resistance, good resistance to acid slags, low thermal expansion coefficient and good thermal shock resistance. It can be used in the ladle lining and critical parts such as the slag line and the outlet. It can also be used in the ladle nozzle, tundish nozzle and pocket block.

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The roofs of the heating zone and soaking zone are constructed with high alumina hanging brick, with a layer of insulation board laid over it. The wall is successively constructed with high alumina brick, fire clay brick, fire clay insulation brick and insulation board. The bottom of heating zone is constructed with magnesia chrome brick, magnesia brick, fire clay brick, fire clay insulation brick and insulation board. The lining of the preheating zone is constructed with fire clay brick. Recently, more and more refractory castables are used in the heating furnace. High alumina cement, refractory castables, clay bonding refractory castables and lightweight casting materials is used in the lining.

Lightweight refractory products mainly include silica insulation brick, fire clay insulation brick, high alumina insulating brick and alumina bubble brick. The bulk density of lightweight refractory products is generally 0.6-1.2g/cm3. Its service temperature is 900-1350℃. alumina bubble brick can be used below 1800℃ for a long time.

Refractory fiber is a type of new efficient fibrous refractory insulation material. The main manufacturing methods include Melting-blowing method, high-speed centrifugation method and colloidal method.

Refractory fiber products mainly include ceramic fiber, zirconia ceramic fiber, high-purity high alumina ceramic fiber, polycrystalline mullite fiber, alumina fiber and zirconia fiber. Besides, materials for low temperature insulation include slag wool and glass fiber.

Refractory fiber products have low bulk density, low thermal conductivity, good thermal stability and mechanical shock resistance. It is soft and easy to cut and construct. Using refractory fiber as the lining can effectively reduce heat loss, save energy and rise the temperature.

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When heated to a certain temperature, glass phase exuded by fused cast AZS forms mullite with binding agents. Bricks should be fired at 1600-1700℃. The frits should have homogeneous chemical composition and a low content of glass phase. Waste bricks have non-homogeneous composition and a high content of glass phase (15%-25%).

When Fused cast AZS is heated, glass phase is melted and exuded. The exuded glass phase has peritectic reaction with the main crystal phase and forms mullite. In this case, mullite and ZrO2 coexists with each other by wrapping and being wrapped. It makes the fused cast AZS scraps fired into a solid brick. The finer the fused cast AZS scraps are, the bigger the specific surface of glass phase is.

After sintered, rebonded fused cast AZS block has a significant change in microstructure.

1) Glass phase in the fine fused cast AZS reacts with Al2O3 and forms mullite.
2) Glass phase in the coarse granular materials is exuded to the surface and forms a mullite layer by reacting with Al2O3. The layer encloses the liquid exuding channel and ensures the peritectic reaction happens within the particles.
3) After glass phase in the coarse granular materials is all exuded, voids and cracks are left.

Compared to fused cast AZS block, rebonded fused cast AZS block has a higher exudation temperature of glass phase. It has good thermal shock resistance, high temperature mechanical properties, creep resistance and corrosion resistance to glass.

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Alpha-beta fused cast alumina block is made of high quality fused alumina as the raw material.

1) White fused alumina
White fused alumina is made of industrial alumina powder as the raw material. It is melted in an arc electric furnace and crystalized by cooling. White fused alumina is white and abbreviated as WFA.

2) Dense fused alumina
Dense fused alumina is made of industrial alumina powder as the raw material with the addition of additives. It is melted in an arc electric furnace and crystalized by cooling. It is gray or hoary and abbreviated as OFA.

3) Sub-white fused alumina
Sub-white fused alumina is also called high alumina corundum. It is made of bauxite as the main raw material with addition of additives. It is melted in an arc electric furnace and crystalized by cooling. It is brown grey or gray and abbreviated as SFA.

4) Gray fused alumina
Gray fused alumina is made of bauxite as the main raw material with addition of additives. It is melted in an arc electric furnace and crystalized by cooling. It is chocolate brown and abbreviated as BFA.

Below 1350 degree, alpha-beta fused cast alumina block has excellent corrosion resistance to glass liquid. It is widely used in the working tank of glass furnaces.

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When using fused brown corundum or white corundum as raw materials, the frits should be smashed and then processed by removing the ferro-silicon alloy and other impurities. White corundum should be processed by removing the flaky sodium aluminate crystals and other low-melting substances. The impurities are easy to be identified since they have low density and float in the surface of corundum frits.

There are a few harmful ingredients in the corundum which will cause poor sintering or cracking, so corundum should be pre-calcined before use. The residual ferro-silicon alloy is oxidized and decomposed into Fe2O3 and SiO2 at 500-1000℃ and Ti in the minerals can be oxidized into TiO2 (rutile), which can cause large volume expansion. After pre-calcining, the stress caused by those decomposition reactions and oxidation reactions can be eliminated during the pre-calcining process and cracks caused by the volume expansion of those impurities can be avoided during the sintering process.

Fused corundum block has large volume, so it should be smashed with drop hammers and other ways and then pulverized. The pulverized fused corundum is stored by size after screened. Fused corundum is hard and difficult to grind. Therefore it is wet ground by ball mills or vibration ball mills. The grain size can be less than 40μm or even 10μm. The iron in the granular material can be removed with electromagnets and the iron in the fine powder can be washed with acids.

The batching of granular materials should be according to the principles of tightly packing, multilevel ratio, less intermediate particles and more fine powder. This can improve the density and sintering of the products. The additives include aluminum phosphate, phosphoric acid, aluminum chromium phosphate, cellulose and pulp waste solution. Among them, he most promising is active phosphate. Recently, ammonium phosphate is on the trial and achieves good results. The mud should be mixed evenly with a moisture content of 3-4%. After high pressure molding, high dense bricks are obtained.

The fused cast alumina block has high purity. It is difficult to sintere and should be sintered at 1800℃. The type of the kilns used depends on the production scale. For small batch production, high-temperature batch kiln is better. For batch stable production, the small high-temperature tunnel kiln is used.

Zhengzhou Sunrise Refractory is a refractory supplier from China. We provide various refractory materials such as fused cast AZS, fused cast alumina block, silica brick, zircon brick, etc..

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Fused cast alumina block can be divided into alpha-beta block, alpha block and beta block.

Alpha-beta fused cast Alumina Block is formed by the compact structure of alpha alumina and beta alumina crystals in a most ideal proportion which is approximately 50% and 50% respectively, where intertwined crystals of both materials result in a very dense structure. It has dense structure and no contamination to glass. It is the ideal refractory materials for channels, spouts and working ends of floating glass furnace.

Alpha fused cast alumina block is an ideal product for the lower temperature zones of the glass melting furnaces due to its high density, superior corrosion resistance and low blister potential. It is also an ideal material for Metallurgical Titanium Furnace because the superior thermal stability.

Beta fused cast alumina block comprises of a majority of beta alumina crystals and a slight portion of alpha alumina crystals in compact structure. Moreover, the intersected texture of large ß-alumina ensures great dimensional stability and great resistance against spalling. Its property of base saturation enables a higher resistance to alkali vapor, thus it has excellent thermal shock resistance and does not form molten droplets. It is the best material for molter crown, port crown, feeder channel, ect.

Recently, the mechanical processing technology of the refractory materials has seen development. The pre-assembling of the refractory materials has already been adopted aboard. After the products are processed, pre-assembled, numbered and accepted, it is transported from the factory. This can save the time of cold repair and hot repair.

Zhengzhou sunrise is a refractory supplier from China. We offers various refractory materials for glass furnaces, such as fused cast AZS, fused cast alumina block, fused cast high zircon block, etc..

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Fused cast AZS block has excellent resistance to the erosion by fly ash to the checker brick in the regenerator, which is confirmed by its application in the burner. Fused cast AZS is durable than other bricks even it is only used in the upper layer of the checker work.

The performance of fused cast AZS block in the crown has been confirmed in the furnace with a small span. It shows excellent resistance. The new fused cast AZS crown structure as well as the insulation method developed by R.E.R from France has been used in the glass furnaces with a span of 11m and large furnaces. It is characterized by the use of light and firm magnetic structure and complete insulation with a 500mm insulation layer.

The limit temperature of silica brick crown is 1600℃, while the fused cast AZS block can be used safely in the 1680℃. AZS also has excellent corrosion resistance to fly ash and vapor of volatile components. Therefore, the temperature of the furnace can be increased to 100℃. Ina addition, there is a low risk of burning of materials. The crown is low, which increases the heat radiation and improve the melting rate and reduce the energy consumption.

Since 1965, the fused cast AZS crown has been used. The crown was initially built with common silica brick, mainly used in the glass fiber and borosilicate glass melting furnace. The fused cast AZS crown as well as the insulation method began to be actually used and its application was even expanded to large soda lime glass melting furnaces. In 1974, the structure was used in large cross-fired furnaces with a span of 11m. Besides, it is also used in the container glass furnace in France and can reduce 130 liters heavy oil per ton.

Zhengzhou Sunrise Refractory Co., Ltd. is a refractory supplier from China. We provide various refractories for glass furnaces, including fused cast AZS, fused cast alumina block, fused cast high zircon block, etc..

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The layer-structure lining is built by putting ceramic fiber products on the steel sheet of the furnace wall layer by layer and then fixing them with heat-resistant steel anchors or in other ways. According to the lining material, the layer structure can be divided into two types: layer structure with ceramic fiber blanket and layer structure with ceramic fiber felt or board.

The layer structure with ceramic fiber blanket can be classified into butt type and lap type, according to the installation method of the hot face of the blanket. The felt or board is mostly installed in the butt type. Both the two types of layer structure can be classified into anchoring-nail-exposed style and anchoring-nail-embedded style according to the fixed way of anchoring nails.

The anchoring-nail-exposed structure is built by tilting the blanket, felt or board on the wall and then fixing it with anchoring nails, fast cards, rotary cards or nuts. Different materials can be used in the lining according to the temperature along the direction of the lining thickness. This structure can greatly reduce the construction cost, improve the insulation performance and is easy to construct and repair. The drawback is its poor resistance to wind erosion. Since the anchors are exposed in the hot face, when the temperature is high, it puts higher requirements on the anchors. The anchor itself is a heat conductor and the ceramic fiber board (blanket or felt) can generate volume shrinkage when use, which may cause gaps in the butt joints and weaken its insulation performance. Therefore, this structure is suitable to low-temperature heat treatment furnace.

The anchoring-nail-embedded style can avoid the exposing of the hot face of the anchoring nails, reduce the heat loss and improve the insulation performance. But it is difficult to overcome the poor resistance to wind erosion. Meanwhile, if it adopts ceramic-cup structure, the ceramic cup is brittle and expansive, which increases the construction difficulty and the cost. If it adopts sinking-hole structure, when the temperature changes, the sinking hole may generate shrinkage and cracks and damage the anchors. Therefore, it is only suitable to the insulation of the low temperature furnace wall.

Currently the tile stacking composite structure can be categorized into ceramic fiber module + tile structure and polycrystalline bar + module + tile structure (from hot face to cold face). Given the actual conditions such as the speed of the burner flame and the composition of the fuel gas, a layer of coating with good resistance to erosion and high temperature may be brushed on the hot face of the ceramic fiber lining. This coating can form a dense protective layer with good resistance to erosion and high temperature.

The thickness of the ceramic fiber lining is up to the structure of the heating devices (flat wall or curved wall), the thermal conductivity of the materials, the average temperature of the cold and hot face and allowed unit heat loss. The material should be selected by taking into consideration many factors including the maximum temperature, the working conditions, the fuel, the atmosphere and the pressure. The selection of the anchor should be based on the temperature of its location and whether it is in direct contact with fuel gas.

The installation arrangement ways of the modules can be divided into parquet floor type and soldier row type. The parquet floor type is a traditional installation arrangement way and was very popular a few years ago. However, with the development of the development of the applied technology of ceramic fiber module, research and practice have proved that, the parquet floor type has some drawbacks. Therefore, it is only used in the bar pasted structure of the hot face. Currently, most programs adopt the soldier row type.

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Fused cast AZS block is composed of 50%-70% Al2O3, 20%-40% ZrO2 and a small amount of SiO2 and other components. Based on the ZrO2 content, it can be divided into AZS 33#, AZS36# and AZS 41#. The most commonly used is AZS 33#, which has a density of 3.1-3.4g/cm3 and maximum service temperature of 1700 degree.

Based on the position of the electrode, the melting methods of fused cast AZS can be classified into the reducing method and the oxidizing method. The electrode of the reducing method is inserted into the melt, while the electrode of the oxidizing method is over the liquid level.

Products made by different methods have different mineral composition as well as different proportions and different content of reducing substances (C, H). All these will affect the exudation temperature exudation amount of glass phase.

Now most manufacturers adopt the oxidizing method, since it can reduce the carbon content to 0.003%-0.006% by long arc melting and blowing oxygen to the melt. Compared to the reducing method, it can produce fused cast AZS block with higher corrosion resistance to molten glass and higher exudation temperature.

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The ceramic fiber materials used to install the ceramic fiber linin include ceramic fiber board, ceramic fiber blanket and ceramic fiber module. The lining is generally 25-50mm, and 50-100mm is preferred.

1) External thermal insulation
The ceramic fiber board is pasted or anchored to the cold surface of the furnace walls. This structure simply needs low temperature fiber products or lightweight bricks.

2) Internal thermal insulation
Ceramic fiber board is pasted on the hot surface of the furnace walls. It has good thermal insulation performance in either batch or continuous furnaces. It can reduce the heat loss of the furnace wall and the regenerative loss.

3) Intermediate thermal insulation
The ceramic fiber layer is installed in the middle of the furnace wall.

The adhesives commonly used include agents made with Silica gel and water glass or mud formulated with Portland cement and sulphate.

Now most furnaces adopt the internal thermal insulation structure, since it has high thermal efficiency, good energy-saving effect and long service life. Of course, in some cases, the structure and construction method should be chosen based on the actual situation.

Zhengzhou sunrise refractory Co., Ltd. is a refractory supplier from China, specializing in various ceramic fiber materials for glass furnaces, such as ceramic fiber board, ceramic fiber blanket, ceramic fiber module, etc.

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The Magnesium Silicate Insulation board is made of sepiolite matrix material (mainly magnesium silicate) by pulping, molding, forming and drying. Within the operating temperature range, it can be used for a long term without aging and deterioration. It is non-toxic and odorless.

The Magnesium Silicate Insulation board features with high structural strength, low deformation after sintering, fine heat-conducting property and damp-proof. Especially its physical performance is quite stable under high-temperature operation. The application of this board can promote the volume stability of the whole liner, reduce furnace surface temperature, eliminate operating force among bricks, so as to ensure furnace’s safety performance and effectively save the energy.

The shell temperature of test ladle that takes Magnesium Silicon Thermal Insulation Board as liner is much lower than that of common ladle, which averagely reduces 75℃, while the maximum temperature reduction will be about 120℃. Therefore, the board application will facilitate to eliminate the deformation of ladle shell materials, and greatly improve operation environment of ladle. The temperature drop rate of molten steel is smaller than that of common ladle, namely average 0.3~0.5℃/min. It indicates that the heat preservation of molten steel is quite great, which can not only save energy and heat losses, but also is beneficial for the constant temperature and rate during steel casting process to ensure the smooth continuous casting.

Magnesium Silicate Insulation Board is mainly used for metallurgy, building materials, furnace heat preservation, fireproof materials, etc. compared to other insulation materials, it is easy to install and cut and has no pollution to the environment, no irritation to skin and no loss during the construction.

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It is a new type of lightweight insulating material which contains approximately 48% alumina, mullite and glass phase or corundum. It has such advantages as high porosity, small volume density, good insulation effect, high mechanical intensity, small thermal conductivity and long service life. For various industrial kilns & furnaces, it is a kind of essential refractory for energy saving and temperature preservation.

High alumina insulation brick is made by mud pouring method. The mud contains about 50% water. By adding a small amount of gypsum, the mud will quickly be solidified. An appropriate amount of phosphoric acid is added. The ratio of the dry raw materials and the phosphoric acid is controled within 1:0.7. Chemical reactions produce CO2. The reason why use phosphoric acid instead of hydrochloric acid and sulfuric acid is that the the phosphoric acid can increase the duration time of bubbles and enhance the structural strength of semi-finished products.

Since CO2 will be produced in the mud, the embryoid bodies should be removed after two hours to ensure that embryoid bodies become strong. Embryoid bodies should be dried for three days at a temperature of 60 ℃. The final step is firing. The semi-finished products should be fired at a temperature of 1600 degrees for about 4 days.

High Alumina Insulating Brick is widely used in lining or insulating layers of various industrial furnaces, and kilns in petrochemical, machinery, ceramic industry, such as lining and insulating layer of high temperature kilns, carbon black stove, gasifier, hydrogen manufacturing furnace and shuttle kiln, etc.

Zhengzhou sunrise refractory Co., Ltd. is a refractory supplier from China, offering various insulation bricks, such as high alumina insulation brick, fire clay insulation brick, silica insulation brick and mullite insulation brick.

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Ceramic fiber cloth and tape are a type of ceramic fiber product with light weight, good high temperature performance, good thermal stability, low thermal conductivity and low resistance to mechanical shock. It is designed for a variety of high temperature, high pressure and easy-to-wear environments. They are mainly used in fire doors and for the insulation of industrial furnaces and high temperature pipes and containers.

Ceramic fiber rope can be divided into ceramic fiber twisted rope, ceramic fiber braided rope, ceramic fiber square braided rope, ceramic fiber circular braided rope, ceramic fiber Matsunawa, flat ceramic fiber packing and flat ceramic fiber square rope. It is mainly used in the expansion joints of various industrial furnaces, insulation of high temperature pipes and insulation of steel junctions.

They are widely used for high temperature static sealing (e.g. door joint or gaskets for flanges), fire protection (e.g. fires proof curtain against welding spark), asbestos substitute, expansion joint, pipe or round duct insulation lagging and for manufacturing of safety products (e.g. safety gloves or apron).

Since Ceramic Fiber Cloth Tape, Rope, Yarn contain about 15% organic fiber, when heated for the first time, as the temperature rises, the organic fiber will be gradually carbonized and there will be smoke and even fire. This is a normal phenomenon and does not affect use. As the temperature continues to rise, the products will gradually turn white and the organic fiber is completely carbonized.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope, yarn.

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Ceramic fiber bulk is made of glass balls or waste glass by melting, drawing, winding and weaving. The diameter of the monofilament is several microns to twenty microns, equivalent of 1/20-1/5 of a single human hair. Each bundle of fiber precursor is composed of hundreds or even thousands of monofilaments.

Ceramic fiber bulk has good insulation performance. According to the physical principle, gas has low thermal conductivity, so excellent insulation materials usually have many air holes inside them. Ceramic fiber bulk has many air holes inside it and its fibers are in irregular arrangement, so it is an excellent insulation material with a low thermal conductivity of 0.03w/cm.k.

Ceramic fiber bulk has advantages of noncombustible, no distortion and no embrittlement. It can resist high temperature up to 700 degrees and has A1 level of combustion performance.

Ceramic fiber bulk has good corrosive resistance to strong acid and good recoverability. It has high tensile strength, more than 1.0kg, so it can resist any shock and vibration. It has low moisture absorption rate, close to zero.

Ceramic fiber bulk does not contain any bonding agent and has no smell and no toxic. Compared with the traditional glass wool and rock wool, it does not contain any bonding agent and will not give off any toxic, acrid smoke at high temperature.

Ceramic fiber bulk is usually used in the interior compartments and ceilings of advanced buildings and for the insulation of metal duct or the inner walls of bellows, noise absorption within the room and sweat control of metal ceilings.

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The walls in four zones as with checkers are subjected to different conditions:
1) Top zone: from the crown skewbacks to one meter under first row of checkers;
2) Mid zone: from the end of the top zone to 1,000°C;
3) Condensation zone: from 1,000°C to 700°C;
4) Lower zone: from 700°C to the Bottom.

The operating conditions are the same as for the crown but with minor load. Low iron basic refractories with a high periclase content and high grade mullite (95-97 percent mullite) are suitable for this area. As far as basic refractories are concerned the operating temperature must be under 1,500°C (1,460-1,480°C) to avoid creep.

Provided the target wall is exposed to the same conditions as the other top zone walls, then the refractory material will be as for the rest of the top zone. However, in the event the target wall is subject to excessive waste gas impingement then fused cast AZS block is recommended.

Checkers protect the mid zone wall. Temperature and load are lower compared to the top area, thus basic refractories with 95 per cent MgO or a good mullite are suitable for this area.

Chemical corrosion is not as strong as in the checkers because bricks are protected by the masonry and only one side is exposed to the chemical attack. Load is higher than on the overhung zones, but temperature is lower. Periclase based refractories, mullite and sillimanite bricks are suitable for this application.

Characteristics of this area are: high load, low temperature and a reduced chemical attack. Basic materials with 90-92 percent MgO, mullite, sillimanite and 44 per cent Al2O3 “super duty” are suitable for this application.

The internal separation walls are fully immersed in the high temperature environment and therefore the operating conditions are severe. They must resist loading at high temperature, and thus they must have high values of refractoriness under load and therefore high creep resistance.

Basic materials are suitable within the temperature limits indicated in the top zone (1,460-1,480°C), while different grades of mullite according to the different zones of the separation wall can be used.

Zhengzhou sunrise refractory Co., Ltd. is a refractory supplier from China, specializing in various refractories for glass furnaces, such as fused cast AZS block, magnesia bricks, silica brick and mullite bricks.

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The main function of crowns is to limit thermal losses. The main operating factors to be considered are temperature, repeated temperature cycling, airborne particulates, volatiles and load. Fuel and glass composition must also be considered when deriving the refractory specifications.

The main refractories for the crowns of glass furnace regenerators include basic refractories, silica brick, mullite brick and alumino silicates refractories. In making the choice, the resistance to creep and chemical attack must be taken into consideration.

The temperature is very important for the refractory choice. Basic refractories have limits in creep resistance. If the temperature is close to 1,500°C and the material is under a strong compression, life limiting creep will ensue. As a consequence, basic refractories can be used only if the operating temperature is lower than 1,500°C (1,460-1,480°C).

Considering only creep resistance, silica brick is the best refractory because of its lack of glassy phase and its different crystalline structure, which avoids plane slipping. Furthermore, creep starts only at temperatures close to 1700°C. Mullite brick is another quality suitable for the crowns for its excellent creep resistance.

Basic refractories have a very good chemical resistance to the alkaline gases coming from the glass furnace, but they are susceptible to carry-over enriched with silica and subsequent forsterite formation at the hot face. This chemical reaction increases volume and leads structure to a collapse.

Basic refractories can be used in the crowns temperatures lower than 1,500°C (1,460-1,480°C). Silica brick is not suggested for crowns because condensation of alkali in the colder zones of the masonry would lead to corrosion, loss of mass and also holes.

Mullite brick reacts with alkali and slags to form a series of layers which prevent alkali penetrating into the refractory and wear proceeds at a minimal rate while the thermo-mechanical properties are preserved. Mullite brick is a good choice for crowns but it must have high mullite content (95-97%).

Zhengzhou sunrise refractory Co., Ltd. is a refractory supplier from China, specializing in various refractories for glass furnaces, such as fused cast AZS block, magnesia bricks, silica brick and mullite bricks.

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Spun ceramic fiber blanket has uniform diameter, long fiber and low content of slag balls. Its interleaving degree, delamination, properties, erosion ressitance, flexibility and tensile strength are all improved, which improves the application performance of spun blanket and reduces the material loss. Spun blanket does not contain any binding agent to ensure that products have good reliability and stability in various environments.

Spun ceramic fiber blanket has low thermal conductivity, low thermal capacity, excellent thermal stability and thermal shock resistance, excellent tensile strength, excellent thermal insulation, good fire protection and sound absorption. It can be used in industrial furnaces, heating devices, high temperature pipe lining, industrial high-temperature reaction equipment, heating equipment lining, power boilers, gas turbine, furnace door, and high-temperature filter materials.

The heat capacity of spun ceramic fiber blanket is only 1/10 of that of lightweight refractory lining and light castable lining. The heat capacity of the lining material is is proportional to its weight. Low heat capacity means less heat absorption of the furnace in the reciprocating operation and higher heating rate. It can greatly reduce energy consumption of the temperature operation control, especially the start and shutedown of the heating furnace.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope and yarn.

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Ceramic fiber module has white color and regular size. It can be directly fixed to the anchor nail on the steel plate of the furnace shell. It has good insulation performance and can improve the integrity of the furnace. It simplifies and speeds up the construction of furnaces and promotes the masonry techniques of furnaces.

It has many advantages over the ceramic fiber blanket.
1) During installation, after releasing the tying, the folded blankets can generate a huge stress, which makes them crowded together tightly without gaps.
2) The flexibility of ceramic fiber blanket can compensate the deformation of the furnace shell and reduce the construction cost. At the same time, it can make up the gaps caused by the thermal changes of the different components.
3) Since it has light weight and low thermal capacity, it can significantly reduce the energy cost during the temperature operation.
4) Flexible ceramic fiber blanket can withstand external mechanical forces.
5) It has good resistance to thermal shock.
6) The ceramic fiber lining requires no drying and maintenance. It can be put into use immediately after the construction is completed.
7) It has stable chemical properties. It is not eroded by acids, bases, water, oil and vapor, except phosphoric acid, hydrofluoric acid and strong base.

It can be used for the furnace lining insulation in the petrochemical industry, metallurgical industry, ceramic industry, glass industry, heat treatment industry and other industries.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope and yarn.

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High temperature insulation fiber developed from the natural asbestos fiber to synthetic glass fiber and then to ceramic fiber. It is characterized by low density, low thermal conductivity, good resistance to thermal shock and mechanical shock, good elasticity and plasticity and good electrical insulation properties. It is a type of practical amorphous inorganic fiber.

Ceramic fiber paper is made of ceramic fiber cotton with a low content of slag balls by pulping, dross removing, molding, vacuum dewatering, drying and cutting.

Since it contains no asbestos, it is environment friendly and is an environmental alternative to asbestos. It has even fiber distribution, white color, no stratification, small slag balls and good strength. It has low thermal conductivity, low thermal capacity, good insulation, good chemical stability and corrosion resistance. The physical property like refractory and insulation keep same when meet with oil, water or steam. The paper is with smooth furnace and good flexibility, can be cut into suitable size. Besides, ceramic fiber paper has excellent dielectric strength; the binder will be burned out when fired.

Due to those advantages, it is widely used in machinery, petroleum, transportation, aerospace and other industries. It can used as welding thermal barriers, castings parcel, plant catalytic converters parcel, ladle parcels, thermocouple protection tube, sealing for furnace door, sealing and insulating pat, expansion joint for furnaces, insulating material for home application, filter material for high temperature, insulation material for glass and metal industry, insulations for car muffler and exhaust pipe, and fireproof.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope and yarn.

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Ceramic fiber first appeared in 1941 in US. Babu Wilcox Company produced ceramic fibers with natural kaolin by the blown process after melt in the electric furnace. In 1990s, with the popularization and application of zirconium-containing fiber and polycrystalline alumina fiber, the service temperature is improved to 1000℃-1400℃. However, due to the quality defects and behindhand application technology, its application is limited. Polycrystalline alumina fibers cannot be made into blanket. The specifications are monotonous, mainly cotton and block. Although the service temperature increases, the poor strength limits its application and service life.

Due to the high production cost, currently ceramic fiber is mainly used as the lining and insulation materials in various industrial furnaces fueled with coal, oil, gas and electricity and high temperature resistant reinforcing material and filter material. As a lining material, it can be used in nuclear reactors, industrial furnaces, metallurgical furnaces, petrochemical reactors, metal heat-treatment furnaces and ceramic kilns. Current insulation lining structures include refractory fiber veneer lining, refractory fiber board / refractory fiber blanket fiber lining, refractory fiber castable lining, prefabricated modular fiber lining and refractory fiber spraying lining. As a insulation material, it can be used for the fill insulation for industrial furnaces and the gaps between refractory bricks and insulation bricks, the insulation for the aircraft jet catheter, jet engines and other high-temperature pipes and slow cooling during the pipe manufacturing process. In addition, it can be used for the insulation of long-distance gas pipelines.

Zirconium-containing fiber is a kind of low-cost versatile silicate fiber made by the melting method. It can be widely used in the hot face lining of various furnaces. In practical applications, ceramic fiber cotton can be directly used as the filling materials, insulation materials and sealing materials of industrial furnaces and used to produce refractory coatings and castables.

Ceramic fiber blanket is a type of semi-rigid plate-like refractory fiber product. It has good flexibility and flexibility and can meet the needs of the construction and long-term use. It is mainly used in the lining of furnaces. Wet ceramic fiber blanket, due to its soft formability, is used in various complex parts. After dried, it becomes light, surface hardening and flexible and has better resistance to wind erosion than ceramic fiber blanket. Ceramic fiber needled blanket, is widely used for the insulation of industrial furnaces and high temperature pipes, due to good mechanical performance and no binders.

Ceramic fiber board is a type of rigid refractory fiber product. Since it contains organic binders, it has excellent mechanical properties and good resistance to wind erosion. It is generally used in the hot face of industrial furnaces and pipes.

Ceramic fiber prefabricated components are mainly used for the masonry of linings. It is convenient and fast to install. Among the ceramic fiber shaped products, the most widely used one is the ceramic fiber pipe shell. It can be used in the construction of small electric furnaces and the bushing of casting risers.

Ceramic fiber paper is usually used in the expansion joints, the nodes of the combustion furnace and plumbing equipment. Ceramic fiber rope is mainly used as non-load-bearing insulation materials and sealing materials.

In addition to insulation materials, ceramic fibers can also be used as reinforced materials and catalyst cutting body for advanced ceramics, metals and plastics.

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Light weight high alumina brick is also called high alumina insulating brick. It contains more than 48% Ai2O3 and mainly consists of mullite and glass phase or corundum. It is usually made of high bauxite and a small amount of clay. After the raw materials are grounded, it is made into mud. Then it is cast and molded and fired at 1300～1500℃. Sometimes industrial alumimum is used to replace bauxite. Inorganic matter is added as ignition loss substance in order to increase the porosity of the refractory.

It has such advantages as high porosity, good insulation effect, high mechanical intensity, small thermal conductivity and long service life. It has high cold crushing strengh, size precision and holds the most stable and lowest thermal conductivity of all insulating refractory bricks at present. Its maximum service temperature is 1350℃. Thermal efficiency and working condition can be improved, energy consumption can be lowered, productivity and significant economic results can be achieved.

It is characterized by low bulk density. The total weight of the furnace body and walls thickness can be reduced effectively.

It has found a wide application in ceramics tunnel kiln, roller kiln, shuttle kiln, coking furnaces of iron and steel industry and other thermal equipment. It is mainly used in lining and insulating layer of areas without strong erosion by high temperature melts. When in direct contact with flame, the surface contact temperature can not be higher than 1350℃.

Zhengzhou Sunrise is a refractory material supplier from China, offering high quality insulation bricks, including High Alumina Insulating Brick, Fire Clay Insulation Brick, Mullite Insulation Brick, Magnesium Silicate Insulation Board, etc..

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Ceramic fiber blanket is made of aluminum silicate with addition of auxiliary materials by the blowing technology. According to the production process, ceramic fiber blankets can be divided into two types: spun needle blanket and blown needle blanket. Especially the quality of products made by the double-side needle process is much better than common ceramic fiber blanket.

Ceramic fiber blanket has low thermal conductivity, good insulation and low thermal capacity, thus it can effectively improve the utilization of energy. It has light weight, good thermal shock resistance and good extension.

Ceramic fiber blanket has uniform diameter, long fiber and low shot content, which greatly improves its properties and performance. It contains no binder agent and has good reliability and stability in different environments.

Ceramic fiber blanket is white and has regular size. It is easy to be cut and install. It can maintain good tensile strength, toughness and fiber structure in neutral and oxidizing atmosphere. Its thermal and physical properties are bot affected by oil and can be restored after drying.

Due to its advantages, it is widely used in many fields such as lining for high-temperature reaction equipment and heating equipment in chemical industry, lining for industrial furnaces, high temperature filter material and fire protection and thermal insulation materials of high buildings.

Zhengzhou Sunrise Refractory supplies various ceramic fiber products including ceramic fiber blanket, ceramic fiber board, ceramic fiber module, ceramic fiber vacuum formed shapes, calcium silicate board, ceramic millboard, ceramic fiber paper, ceramic fiber bulk, and ceramic fiber cloth tape, rope and yarn.

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Silica is the main component of silica brick. It occurs in a variety of crystalline modifications, e.g. quartz, tridymite, and cristobalite and also as an under-cooled melt called quartz glass. The crystalline modifications each have a high and low temperature forms which can transform reversibly. The crystal structure of the individual SiO2 modifications can differ widely, so that distinct density changes occur during transformation. This is of great importance during heating and cooling because of the change in the volume.

Quartz requires the smallest volume and the quartz glass the largest. During firing above approximately 900 ℃, quartz transforms into the other modifications and melt completely at 1725℃. During slow cooling, reversible volume decreases take place which are a result of the spontaneous transformation of the crystal structure from the high to the low temperature modification. The reversible and irreversible volume effects can cause considerable stress within the refractory brick structure.

Any common silica brick having large non-transformed silica content is undesirable because it exhibits extraordinary expansion so as to impair stability of industrial furnace which employs such brick as the refractory. Therefore, the extent of transformation of silica is one of very important factors which have to be considered in designing an industrial furnace in regard to selection of material and evaluation of adequateness of the use of the selected material.

Silica brick provides a high temperature resistant and non-reactive lining. It is characterized with its good resistance to spalling at high temperatures. It also retains their rigidity, are lightweight, have a good resistance to most fluxes present in coke ovens, and offer high resistance to abrasion. It has a relatively long lifespan. It is also nonreactive with the melted glass whereas other refractories, such as magnesia brick, could discolor the final product.

Silica brick is used as a refractory in building and repairing industrial furnaces, such as coke ovens, hot blast stoves and glass furnaces. Silica brick crowns have been successfully used in glass furnaces for producing container, float glass, table-ware and TV panel glass. They have the attributes of a relatively long life, excellent insulation at a low cost, and limited defects as silica is the dominant oxide.

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The casting temperature is the temperature of the melt when it is poured into the mold. The casting temperature of fused cast AZS can be as high as 1820-1840℃. The viscosity of the melt is up to the chemical composition and temperature of the melt. The chemical composition is up to the formulation. The casting temperature is crucial since the higher the temperature, the lower the viscosity, the better the flow-ability. However, if the temperature is too high, the temperature difference between the casting and the mold is small, which will increase the shrinkage stress and cause cracks.

The casting speed determines the casting time. Every casting products has its best casting time. Improper casting time will cause many defects. If the casting speed is too fast, the stream will be coarse and the flowing speed will be too fast, which will produce big impact force on the mold. The force may destroy or melt the mold and cause protrusions. Additionally, gas will be brought into the mold and produce a thin shell filled with gas and bubbles in the casting. Besides gas, raw materials in the furnace mouth may be brought into the melt and cause defects. Conversely, if the casting speed is too slow, it will produce defects such as loose corners, knots, sand and pouring shortage.

Back pour refers to the process of repouring some melt into the shrinkage cavities after the casting is completed. Generally, small bricks are solidified quickly and do not require back pour. Medium bricks can be repoured. Large bricks require back pour and it takes a long time. Back pour is one of the effective ways to reduce the shrinkage cavities and improve the bulk density.

Zhengzhou Sunrise is a refractory material supplier from China, offering high quality refractory materials for glass furnaces, including fused cast AZS block, fused cast alumina block, fused cast high zirconia block, mullite brick, zircon brick, alumina bubble brick, magnesia brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, etc..

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Fused cast refractory materials are widely used in glass furnaces to resist corrosion by the molten glass. Such a quality is especially due to the low apparent porosity of these materials. First generations of these products is fused cast AZS, which is widely applied to soda-lime furnaces. Then fused cast high zirconia block containing 90% or more of ZrO2 was developed to answer to special needs for the manufacturing of special technical glasses (LCD screens, lead crystal) and very corrosive glasses (boron-silicate glasses).

Fused cast high zirconia block is designed to operate in extreme condition and also require control of the making process. Elaborated by a fused cast process followed by a controlled cooling step, these materials exhibit specific thermal and mechanical properties.

Fused cast high zirconia bricks are made of artificial synthesis high purity raw materials through special casting process. The crystalline texture consists of baddeleyite and with the characteristics of excellent high temperature & corrosion resistance, low blister and stoning potential. These advantages can prevent liquid glass from pollution effectively.

In high zirconia fused cast refractories, the majority of the refractory crystalline structure are composed of baddeleyite crystals (ZrO2). During the cooling process, zirconia transforms successively through cubic, tetragonal and monoclinic form, with tetragonal and monoclinic forms exhibiting anisotropy in thermal expansion along their crystallographic axes. The resulting complex microstructure is made of numerous different crystallographic domains called variants. Finally, the shift from the tetragonal to the monoclinic structure is responsible for a large volume expansion which causes cracks. The manufacturing process must be rigorously controlled, in particular the cooling rate after fusion, in order to limit mechanical stresses induced by important thermal gradients and the martensitic tetragonal–monoclinic transformation of zirconia.

When heated, fused cast high zircnoia block undergoes a volume shrinkage at about 1150℃，due to the crystal transformation from monoclinic crystals to tetragonal crystals in accordance with the crystal transformation specific to baddeleyite crystals. When cooled, it undergoes a volume expansion at about 950℃ due to the crystal transformation from tetragonal crystals to monoclinic crystals. The volume expansion may cause cracking, and in an extreme case, the refractory undergoes a spalling phenomenon due to many cracks.

The transformation of the baddeleyite crystals is absorbed by a matrix glass. SiO2 is essential for forming the matrix glass. However, if the SiO2 content is too high, the corrosion resistance tends to deteriorate. The Al2O3 component plays an important role in adjusting the relation between the temperature and the viscosity of the matrix glass, and reduces the concentration of the ZrO2 component in the matrix glass.

Fused cast high zirconia brick has wide application in a wide range of super high temperature furnaces and kilns, especially special glass and high quality glass furnaces.

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ZrO2 is widely used in the refractory for the glass industry, metallurgy industry, construction industry and chemical industry, because it has high melting temperature, good thermal shock resistance and high chemical stability. Zirconia refractories are mainly used in demanding areas of glass furnaces such as the superstructure, the melting zone, the sidewall and the throat.

The main types of zirconia refractories include zircon bricks, dense zircon bricks, fused cast AZS block, fused cast zirconia mullite block and bonded again AZS bricks.

In the metallurgical industry, based on the materials, zirconia refractories can be divided into zirconite refractory, zirconia refractory, aluminum zirconium refractory, calcium zirconate refractory, zirconium diboride refractory and modified zirconia refractory.

Zirconite refractory features high temperature performance, good resistance to acid slags, good corrosion resistance, low thermal expansion coefficient and good thermal shock resistance. It can be used in the ling of the ladle.

The raw materials for zirconia refractories include zirconite refractories in various sizes and various zirconia materials. The molding methods include slurry casting method, machine pressing method and isostatic pressing method. Different molding methods have different requirements for the grains of raw materials. Products made in different methods have different performance and applications, but all have the feature of good resistance to high temperature and corrosion.

Aluminum zirconium refractory is developed based on the aluminum carbon refractory. It is mainly used in the ladle, tundish, slide gate brick, long nozzle, stopper and outlet. Compared to aluminum carbon refractory, it has better resistance to oxidation, thermal shock and corrosion, higher strength and longer service life.

Zhengzhou Sunrise is a refractory material supplier from China, offering high quality refractory materials for glass furnaces, including fused cast AZS block, fused cast alumina block, fused cast high zirconia block, mullite brick, zircon brick, alumina bubble brick, magnesia brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, etc..

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There are 4 commonly used casting methods of fused cast AZS, including normal casting(PT), Tilt casting(QX), Reinforced casting(ZWS) and Void-free casting(WS).

It adopts general casting risers and the riser will be removed in the hot state. The shrinkage cavity in brick is located under the casting scar, due to volume shrinkage from liquid-solid transform and rapid solidification of a casting. The feasible limits of cavity can be evaluated and indicated by the volume-weight testing of blocks in-situ according to the technical specifications.

PT fused cast AZS block is always cheap and used in the areas with no serious corrosion such as top crown, superstructure and feeder channel. The surface with scars should not be used as the working surface.

In this method, the mold is inclined at an angle. The shrinkage cavity in brick disperses at one end of the brick and a completely dense zone forms at another end. The feasible limits of cavity can be evaluated and indicated by the volume-weight testing of blocks in-situ according to the technical specifications. Meanwhile, blocks which height less than 900mm are not suitable to be manufactured by this process.

QX fused cast AZS block is generally used in the sidewall of glass furnaces.

Similar to WS, merely a few shrinkage voids remain in upper part of the body. A little part of the cavity will be remained at the end of the block after the header cutting. Block evaluation in-situ begins from the determination for the feasible size and deepness of cavity remainder at first and then to the volume-weight testing of blocks according to the technical specifications.

ZWS fused cast AZS block is always used in the sidewall of glass furnaces.

Additional liquid from the header fills sufficiently into a casting and the header is then cut off, so no shrinkage cavity exists in brick body. Block evaluation in-situ includes the acceptance or rejection for somewhat trace of cavity remainder which perhaps appeared and the volume-weight testing of blocks according to technical specifications.

WS fused cast AZS block has a wide application in the glass furnaces such as sidewall, tank bottom, feeder channel, doghouse, throat, dam wall, electrode wall and corner wall.

Sunrise is a refractory material supplier from Zhengzhou, China, supplying high quality fused cast AZS blocks manufacturing in different casting methods (PT, QX, ZWS and WS). Sunrise will be present at Vitrum 2015 in Milan, Italy from October 6, 2015 to October 9, 2015. Visit us at Booth U13, Hall 22.

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Sidewall and bottom of melter predominately consist of fused cast AZS block, whereas sintered zirconia mullite brick in some cases can be applied to bottom area, where the application condition is not that demanding. Beneath the fused cast AZS lie the chamotte block at the very bottom, in between AZS ramming mix is filled. In corner area fused cast AZS with Void Free Casting is used exclusively. Fused cast AZS is so far the primary refractory brick for glass furnace.

In tin bath, alumina forming brick such as sillimanite and bottom block are used typically.

Silica brick is used also quite frequently in glass furnace. It finds its application for melter crown, front wall, breast wall and gable as well. It is the traditional choice for the crown.

α-β Fused cast alumina block is used extensively for breast wall, as well as sidewall and bottom of cooling zone. Fused cast α-βalumina block and Fused cast βalumina block are also used in the crown and superstructure.

Direct-bonded magnesia chrome brick is most suitable for upper checker, where strong alkali corrosion exist, or lower and middle checker, where sodium sulfate condenses. There are several substitute brick of chrome magnesia for checker chamber, among them are magnesia zirconia brick, magnesia forsterite brick and magnesia alumina brick. While the first two have similar thermal properties and usage as magnesia chrome brick, magnesia alumina brick is usually used for the middle checker of small regenerator. Light weight magnesia forsterite brick is used for the insulation layer of checker chamber. Sillimanite brick can be used also for checker in low temperature area (below 800°C). In principle the refractory material used for wall is in line with that of checker brick at the same height.

Sunrise is a refractory material supplier from China. The main products of Sunrise include fused cast AZS block, fused cast alumina 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, etc..

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Crown of glass furnaces are subjected to long-term thermal attack and chemical corrosion due to alkali vapor. It also need to be heavily insulated to reduce the energy loss. So it requires volume stability, low permeability, low conductivity, and high refractoriness of refractories in this area.

Silica refractories are the preferred material for crown construction due to its affordability, low stoning potential, insulating capability, resistance to creep, low thermal expansion after 600°C and compatibility with the batch material. They have been used for the construction of glass melting furnace for over a century. Although today the use of silica bricks is restricted to crown and superstructure, the steady improvement in production of silica bricks has led to greater chemical purity and stricter dimensional tolerances over a wide range of shape and sizes. To meet the demanding requirement of oxygen-fuel furnaces, fused cast alumina block is used due to its excellent resistance against acid slag, chemical corrosion and alkali vapor.

The superstructure of the furnace will suffer from high temperature and chemical attacks by volatile products and dust which settle on the walls and attack refractory products characterized by a progressive wear of refractory in contact with the glass. Refractories in this part are required to have a high thermal shock resistance and corrosion and erosion resistance.Fused cast AZS block, Zirconia-Mullite brick and Mullite brick with high density, low porosity, good hot strength and good sag resistance are used in this area.

In contact with melt glass, refractories in those areas suffer high Temperature, and glass corrosion. Chemical reactions also take place between refractories and molten glass, fluxing agents, and/or volatile components. Erosion can follow; washing away refractory grains after the original bond has dissolved. With a high refractoriness, high thermal resistance, a low reaction with melt glass, a very strong glass corrosion and vapour resistance, Zirconia-Mullite bricks and Fused Cast AZS are installed on the bottom or in direct contact with sidewalls.

These areas of the furnaces are subject to special intense aggression in the long campaigns because of the chemical reactions between refractory material and hot gas. A higher performance of the refractory and insulating material is required in these cases in order to attain better heat efficiency. A regenerator consists of a regenerator chamber in which a checker work (or just checkers) of refractory bricks has been stacked. Due to high stability, high thermal shock resistance, low thermal expansion, high refractoriness and the high resistance to basic slags, Magnesia bricks are normally used in the regenerator including area above checker work and crown. With a high alkali resistance and creep resistance, fireclay bricks are particularly suitable for the lower parts of regenerator.

Besides refractories mentioned above, insulating refractories with low conductivity and good mechanical strength are used to reduce heat loss in areas where abrasion and wear by aggressive slag and molten metal are not severe. The insulating materials can lead to savings in fuel cost and a more rapid heat-up. After the furnaces are installed, unshaped refractories such as special ramming &patching masses are used to repair some parts of the furnaces to extend the furnace’s life until the end of the campaign.

Sunrise is a refractory material supplier from China. The main products of Sunrise include fused cast AZS block, fused cast alumina 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, etc..

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Fused cast refractories are manufactured by melting mixtures of raw materials in an electric furnace at a temperature exceeding 2000°C. Then cast the melt into molds of prescribed shapes. Finally cool and solidify them under thermal insulation in many cases. High density, small or large shapes are obtained. When appropriate, a finish work of drilling or cutting(to get different shapes) is made by grinding with diamond tools.

The dense crystalline structure provides the fused cast bricks with superb strength, corrosion and erosion resistance at very high temperatures. They are quite stable against aggressive melts such as glass and molten metal oxides, but their thermal stability is usually not very high. Fused cast refractories always have a very low and closed porosity but contains voids.

Fused cast refractories are the preferred refractories in contact with glass melts, due to the chemical stability, impermeability, and resistance to corrosion and erosion at the working temperatures in the glass melting furnaces. Therefore, used cast refractories are widely used in the glass industry as a lining for glass melting furnaces. They are also used in various other industries such as iron & steel, aluminum, petrochemistry industries.

Fusion cast refractories are normally formed from alumina usually along with zirconia and silica. Proportions of other minerals such as calcia, chromia and magnesia may be added to control the crystalline structure and physical properties of the end products. Based on the mineralogical composition, fused cast refractories can be divided into:

Fused cast AZS block is abbreviated as AZS because it contains Al2O3－ZrO2－SiO2. Based on the zirconia content which basically defines their corrosion resistance, fused cast AZS blocks can be divided into Fused Cast AZS—33# (33% ZrO2), Fused Cast AZS—36# (36% ZrO2) and Fused Cast AZS—41# (41% ZrO2). The corrosion resistance increases with growing ZrO2 content. They are the most widely used materials both in glass contact and superstructure of glass melting furnaces due to the very high glass and vapor resistance.

Fuse cast alumina block contains over 90% Al2O3 and are a kind of pure alumina block which has excellent resistance against acid slag and chemical corrosion. Thanks to their high purity, they are perfect complements to the AZS blocks for sensitive applications. According to the crystallographic analysis, Fuse cast alumina block can be divided into alpha Fuse cast alumina block (almost 100% alpha alumina crystal), beta Fuse cast alumina block (almost 100% beta alumina crystal) and alpha-beta Fuse cast alumina block (approximately 50% alpha and 50% beta respectively). Its neutrality against alkali vapors makes it the best choice for the downstream part of superstructures in demanding applications.

The Fused Cast high zirconia block contains at least 80% of ZrO2 with particularly excellent corrosion resistance against molten glass and low contamination properties. Therefore, it has been widely employed as refractory materials in contact with molten glass in a glass melting furnace.

Fused cast skid rail blocks are mainly made from alumina and zirconia. They are of various types including steel discharging platform brick, skid rail block and iron discharging tank blocks. They feature great strength, good wear and fused slag corrosion resistance as well as long service life. It is mainly used in areas that require high abrasion and temperature resistance, such as gliding rail bricks in steel pusher metallurgical furnaces, the tapping platform style walking beam furnaces, and also as the interior for destructors.

Fused Cast Mullite blocks is characterized by high resistance to acid corrosion and erosion, good high temperature resistance and good thermal shock resistance. It shows high performance on reheating furnaces' beds, skid rails, and for the linings of industrial waste incinerators. It is widely used in the metallurgical industry, glass industry, ceramic kiln, and cement industry, etc.

Sunrise is a refractory material supplier from China. The main products of Sunrise include fused cast AZS block, fused cast alumina 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, etc..

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Fused cast AZS block has many chemical and physical properties over other refractory materials, such as high temperature resistance, dense crystal structure, low porosity, high mechanical strength, good chemical stability, good corrosion resistance, good thermal stability(1200℃) and high exudation temperature of glass phase(>1400℃). Due to the features mentioned above, it is widely used in the glass industry.

It is important to select high quality raw materials and improve the purity of the raw materials. Any change of the chemical composition can change the crystal structure. Too much SiO2 can cause the formation of mullite and the decrease of glassy phase and corundum, which will destroy the crystal structure and make the structure loose. ZrO2 has the features of high temperature resistance, high mechanical strength, good corrosion resistance to glass and good chemical stability, but the drawback is its bad thermal stability at 1000-1200℃.

The corrosion resistance to glass of fused cast AZS is related to not only the content of ZrO2 but also its micro-structure. The denser its micro-structure, the better its corrosion resistance to glass. Too much ZrO2 will make its micro-structure loose and the baddeleyite will drop into the glass melt, which will cause glass defects such as stones, stripes and bubbles and reduce the service life of the glass furnaces. Therefore, its corrosion resistance to glass is not proportional to the content of ZrO2. Besides, with the increase of ZrO2, the melting temperature and viscosity of the glass melt also increases, which increases the difficulty of manufacturing and casting.

The content of Na2O and the impurities such as Fe2O3, TiO2, CaO, MgO will also affect the quality of fused cast AZS. Therefore, the stability of chemical composition is important for the quality of fused cast AZS and the service life of the glass furnaces. Sunrise offers high quality fused cast AZS block 33#, 36# and 41#.

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According to the depth of the cracks, the cracks of fused cast AZS can be divided into surface cracks and deep cracks (or internal cracks). The surface cracks include longitudinal cracks, transverse cracks, electrical cracks and corner cracks. The deep cracks are mainly micro-cracks caused by the crystal phase transformation of baddeleyite. According to the thermal state of the melt, the cracks can also be divided into high temperature cracks and normal temperature cracks.

The cracks generally start from the corners and mainly in the edge and seldom in the center. The larger the size, the more possible to form cracks. The more complex the shape, the easier to miss angles and edges. The darker the block, the more the cracks. The cracks of fused cast AZS block are also related to its micro-structure. The denser the micro-structure, the less the cracks.

The reasons that cause the cracks are as follows:
1) During the cooling process, the temperature in the surface drops faster than in the inside, which causes a big temperature difference between the inner and outer layer. The temperature difference causes inconsistent shrinkage between the inner and outer layer, which causes the thermal stress. The thermal stress may broke the surface and cause cracks. The thermal stress is generally proportional to the temperature difference.
2) During the casting process, due to the gas, impurities or the uneven surface of the mold, the solidified shell grows unevenly in the early stage. The thermal stress concentrates in the thin parts and may cause cracks. Although the cracks can be filled with the residue, the crystals formed in those parts are vulnerable. Shrinkage of the melt when solidifying may cause cracks again.
3) The crystal phase transformation of baddeleyite can cause volume change. At 1050℃~950℃, baddeleyite is transformed from the tetragonal crystals to monoclinic crystals, which cause 9% volume expansion. The volume change and the temperature difference between the inner and outer layer produce a stress, which is the main reason of deep cracks.

Since cracks can seriously affect the quality of fused cast AZS, cracks must be avoided. Careful operation and oxidizing production can effectively reduce or avoid cracks. Sunrise offers high quality fused cast AZS block 33#, 36#, 41# for glass furnace. High purity raw material, scientific formula, advanced technology and professional guide all contribute to high quality fused cast AZS production.

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According to the depth of the cracks, the cracks of fused cast AZS can be divided into surface cracks and deep cracks (or internal cracks). The surface cracks include longitudinal cracks, transverse cracks, electrical cracks and corner cracks. The deep cracks are mainly micro-cracks caused by the crystal phase transformation of baddeleyite. According to the thermal state of the melt, the cracks can also be divided into high temperature cracks and normal temperature cracks.

The cracks generally start from the corners and mainly in the edge and seldom in the center. The larger the size, the more possible to form cracks. The more complex the shape, the easier to miss angles and edges. The darker the block, the more the cracks. The cracks of fused cast AZS block are also related to its micro-structure. The denser the micro-structure, the less the cracks.

The reasons that cause the cracks are as follows:
1) During the cooling process, the temperature in the surface drops faster than in the inside, which causes a big temperature difference between the inner and outer layer. The temperature difference causes inconsistent shrinkage between the inner and outer layer, which causes the thermal stress. The thermal stress may broke the surface and cause cracks. The thermal stress is generally proportional to the temperature difference.
2) During the casting process, due to the gas, impurities or the uneven surface of the mold, the solidified shell grows unevenly in the early stage. The thermal stress concentrates in the thin parts and may cause cracks. Although the cracks can be filled with the residue, the crystals formed in those parts are vulnerable. Shrinkage of the melt when solidifying may cause cracks again.
3) The crystal phase transformation of baddeleyite can cause volume change. At 1050℃~950℃, baddeleyite is transformed from the tetragonal crystals to monoclinic crystals, which cause 9% volume expansion. The volume change and the temperature difference between the inner and outer layer produce a stress, which is the main reason of deep cracks.

Since cracks can seriously affect the quality of fused cast AZS, cracks must be avoided. Careful operation and oxidizing production can effectively reduce or avoid cracks. Sunrise offers high quality fused cast AZS block 33#, 36#, 41# for glass furnace. High purity raw material, scientific formula, advanced technology and professional guide all contribute to high quality fused cast AZS production.

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Most refractory materials for glass furnaces are large in size, which makes the manufacturing technology more complicated. The refractory materials must meet the particular requirement of the glass industry.

The glass melt can corrode the refractory materials. The refractory fragments may drop into the glass melt and cause stripes or stones in the glass. In many cases, when the refractory materials are corroded, bubbles may be formed in the glass melt near the wall. Since the viscosity of the glass melt is high and the density of the glass melt and the refractory materials is similar, the bubbles and the refractory fragments are remained in the glass melt.

The refractory materials for glass furnaces, especially the fused cast AZS, should meet the requirements as follows:
1) Sufficient mechanical strength
2) At the operating temperature, have good resistance to mechanical load
3) Have good corrosion resistance to the components of the batch materials and glass.
4) Have low potential of causing stones, stripes, bubbles and coloring.
5) Have good thermal shock resistance.
6) Have low thermal expansion at the operating temperature.
7) Have accurate shape and size and meet the technical criteria.

Sunrise is a refractory material supplier for glass furnaces from China. We provide various refractory materials for glass furnaces, including fused cast AZS, fused cast alumina block, silica brick, zirconia brick, high alumina brick, silicate brick, etc..

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The life of glass furnaces can be expanded from 11-15 months to 3-4years, even longer. The melting temperature of the glass can be increased from 1450 ℃ to 1550 ℃, even up to 1600 ℃. The glass defects are reduced and the quality of glass is improved. The production capacity of the glass furnace can be increased by 20-30%.

The damage of fused cast AZS is mainly caused by chemical attack and thermal stress. The quality and property of fused cast AZS plays a remarkable influence on the life of glass furnaces and quality of glass. The use of poor quality bricks will not only result in frequent shutdown and repair, limiting melting temperature and reducing the furnace production, but also shorten the life of furnaces, cause glass defects (stripes, stones, etc.) and reduce the quality of the glass.

When selecting the size of fused cast AZS, the furnace design principles and the producing conditions of fused cast AZS must be taken into account. When the dimension is too big, it tends to crack and will increase the difficulty of packaging, transport and masonry. For the shaped brick, the feasibility of each production procedure and the specialty of the casting method should be taken into account.

The corner brick, dam block, bubble brick and doghouse always employ the fused cat AZS block 41#. The gaps between bricks should be less than 0.5mm. The bottom of the brick should not have voids. The brick should not contains too many impurities. If the color of the brick is blue, there may be too much C in the brick. The cutting will directly determine the degree of convergence during masonry. The smaller the gaps are, the longer the life of the glass furnace is.

Sunrise offers different types of fused cast AZS block, including AZS 33#, AZS 36# and AZS 41#. Our fused cast AZS block is made of high quality raw materials and advanced technology. It has been widely used in the glass furnaces and improves the life of glass furnaces effectively.

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How to decrease the corrosion rate of sidewall blocks and improve the corrosion resistance is the key to prolong the service life of sidewall blocks. It is well-known that controlling the operation temperature is one of the effective approaches to prolong the service life of refractory blocks. In different areas and different periods, different cooling methods should be adopted to achieve the desired the results.

In the top parts of the sidewall where are not insulated. In horseshoe flame glass furnaces, as the flame is heating in the surface of glass melt, the temperature of the upper parts of the glass melt is higher than that of the lower parts. Silicate is formed and the refining of glass melt produces a lot of bubbles. Heat convection is very severe here. As a result, the corrosion rate of is bigger there. To solve this problem, it is necessary to select and design the cooling fan reasonably. The cooling should be started slowly at first and then increases gradually to reduce or avoid the thermal stress caused by temperature gradient.

The service life of fused cast AZS block lasts about 3-5 years. During the preheating of the glass furnaces, cracks may be formed. After 2-year operation, there will be holes in the body of the brick. Glass melt may exude though the holes and cracks. To solve these problems, a single-point, focused and forced air cooling method can be adopted, which can crease the viscosity and reduce the temperature of the bricks.

Some special parts of the melting zone is corroded at the fastest rate and not easy to repair. Due to strong mechanical erosion, the glass furnace can just be used for 2.5 years before cold repair. Air and spray mixed cooling method can be adopted here. It is easy, stable and effective. It avoids the problems caused by the water cooling method.

Shower cooling method is mainly used in the middle and upper parts in the later period of the glass furnace campaign. 3 years after the cold repair, the problem of glass melt exudation may occur in these areas. As there are layers of insulating materials here, forced air cooling and water cooling method can not be used here. Compared to other methods, shower cooling method is more suitable for this parts.

Sunrise offers various high quality refractory materials for glass furnaces, including fused cast AZS, fused cast alumina block, zirconia block, mullite block, silica block, magnesia block, etc..

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The main crystal phase of Fused cast AZS consists of corundum, baddeleyite and glass phase. The glass phase can reduce the expansion or shrinkage of ZrO2 within the above temperature range and prevent cracking. However, the glass phase is easy to be corroded and cause corrosion of the fused cast AZS and glass defects.

Fused cast AZS exudation exhibits a shiny "wet looking" appearance at the surface of blocks during heat-up process and beginning of a furnace campaign. This situation tends to stabilize all along the campaign life, with a generally moderate dripping of a viscous glassy phase into the smelted glass.

Fused cast AZS exudation at high temperatures, can lead to the formation of defects in the glass, especially during furnace start-up. It is only a short-term cause of glass defects. Fused cast AZS exudation from a glass contact surface is not very visible than that in the superstructure.

In the glass furnaces, a portion of the glass phase of fused cast AZS block exudes onto the superstructure surface during furnace heat-up, until the furnace has achieved stable temperature profile. The exuded glass, often containing small zirconia crystals, tends to run down into the glass bath. This is a major concern to glass producers since this glassy phase often causes defects, such as viscous knots and stones.

To solve this problem, low exudation fused cast AZS has been developed. With modification of chemical compositions and glass phase, it offers low exudation level and maintains all other positive characteristics of fused cast AZS.

Sunrise offers various refractory materials for glass furnaces including fused cast AZS, silica brick, fireclay brick, high alumina brick, silimanite brick, mullite brick, etc..

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