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Ceramic fiber module is made of ceramic fiber blanket by folding and compressing. Currently, it gradually becomes the first choice for the thermal insulation of industrial furnace linings.

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.

Ceramic fiber paper is a type of sheet product made of ceramic fiber with addition of additives. It has good high temperature performance and good insulation performance. It is can be used as high temperature insulation materials, high temperature air filtering materials and high temperature buffer materials.

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.

Ceramic fiber is a kind of light weight fibrous refractory. It has light weight, good high temperature performance, good thermal stability, low thermal conductivity and small specific heat. Compared to traditional insulation bricks and refractory castables, ceramic fiber products can save 10-30% energy.

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.

Light weight high alumina brick is an ideal insulating refractory, with advantages of high strength, low thermal conductivity, good insulation property and low price. For various industrial kilns & furnaces, it is a kind of essential refractory for energy saving and temperature preservation.

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..

Ceramic fiber blanket, also called aluminum silicate fiber blanket, is a type of insulation refractory material, featuring high strength, light weight, non asbestos and organic binder, good high temperature stability and good insulation performance. It can effectively reduce the weight of high temperature equipment and heating time and save energy.

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.

Silica brick is one of the most widely used high temperature refractory materials. Silica brick is a light yellow refractory product made from silica rock that contain at least 90 percent SiO2. It is used primarily in coke ovens and glass furnaces. It is also used in other applications, such as glass tank walls, acid practice electric furnaces, tunnel kilns, and regenerators.

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.

Casting is an important step of the manufacturing process that has great influence on the quality of the fused cast AZS block. Key factors that affect the casting process of fused cast AZS include the casting temperature, casting speed, the casting time and back pour.

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..

Fused cast high zirconia block is a new type of fused cast refractory. It is specially designed refractory for glass furnace application. It features excellent corrosion resistance to molten glass due to its dense microstructure.

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.

With the development of technology, a variety of zirconia refractories have been developed. Recently, zirconia refractory, as a new type of refractory, has been widely used in the metallurgy, construction and chemical industry.

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..

Casting refers to a manufacturing process by which the melt is poured into a mold after raw materials are melted in the electric furnaces, which contains a hollow cavity of the desired shape, and then allowed to solidify. Although the process is short, it is a complex process and every step is related to the quality of the final products.

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).

PT-Normal casting

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.

QX-Tilt casting

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.

ZWS-Reinforced casting

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.

WS-Void-free casting

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.

Refractories are the main building materials for glass furnaces. It has a decisive impact on the quality of glass, energy consumption and the cost. The development of glass melting technology mainly depends on the development and quality of refractories.

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..

Refractories performance affects glass manufacture in the production cost and the quality of the glass. Refractories in different areas of a glass furnace suffer different operating environment. So different types of refractory are used in the different parts of the glass furnaces.

Crown Refractories

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.

Superstructure Refractories

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.

Bottom and Lower Side wall Refractories

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.

Regenerator Refractories

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..

Fused cast refractories are materials that are produced by melting the raw material of the desired composition and then casting molten refractories in molds. They are widely known for having high corrosion resistance which are entirely different in the crystalline structure and the process for their preparation from fired or unfired bonded refractories due to closed pores.

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

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.

Fused Cast Alumina Block

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.

Fused Cast High Zirconia Block

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 Block

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 Block

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..

Fused cast AZS block is the essential refractory material used in the demanding areas of glass furnaces. The quality of fused cast AZS can affect the quality and production of glass and the service life of the glass furnaces. The chemical composition of fused cast AZS is one of the key factors that determine the crystal structure and the properties.

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#.

Cracks are the defect of fused cast AZS block which will seriously affect the quality of fused cast AZS and economic benefits. There are different kinds of cracks that are caused by different reasons.

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.