Zirconium-containing refractories are made of natural zircon sand or industrial ZrO2. ZrO2 has good chemical resistance. Adding ZrO2 or zircon sand into some products can improve their chemical stability.
Typical zirconium-containing refractories such as fused cast AZS consist of eutectic crystal of baddeleyite and corundum or eutectic crystal of baddeleyite, corundum and mullite. The crystal structure makes it have great resistance to molten glass.
Corundum refractories and high alumina refractories have good chemical stability and high temperature performance, but poor thermal stability. With the addition of ZrO2, their thermal shock resistance can be greatly improved.
Depending on the purity requirement, zirconium-containing refractories are directly made of industrial ZrO2 and zircon sand or made by adding industrial ZrO2 and zircon sand into other materials. Sintered AZS brick for the glass furnace is made of high purity zircon sand. Fused cast AZS is made of industrial ZrO2 and zircon sand. High alumina brick with strong spalling resistance for the cement kiln is made by adding zircon sand into high alumina raw materials.
For continuous casting refractories, except fused cast high zirconia block, other zirconium-containing refractories are always made of zirconia produced by synthesis.
Zirconium-containing refractories generally have high melting temperature, high chemical stability, good resistant to aggressive molten metal, slags and molten glass and good thermal shock resistance.
Zirconium-containing refractories are generally used for high-temperature critical parts, such as ladles and the slag line of continuous casting sizing nozzle and submerged entry nozzle in the metallurgy industry; the melter, superstructure, sidewalls, and throat in the glass furnaces; the transition zone and suspension preheater in the cement kiln.
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..
Monday, August 31, 2015
Friday, August 28, 2015
Corrosion Mechanism And Refractory Selection Of The Glass Furnace Feeder Port
Feeding is one of the most important parts of the melting process and can affect the melting rate, glass quality and fuel consumption. The feeder port is one of the important parts and weak points of the glass furnaces. It is subjected to severe conditions and easily to be damaged.
The feeder port consists of feeder pool and the front wall. It is subjected to the corrosion by molten glass, erosion by the batch materials and dust, wear by the liquid and the impact of the flame.
The front wall usually adopts L-shaped block. Fused mullite block or AZS block is used. Its outside is insulated with ceramic fiber blanket.
The feeder pool is a rectangular pool that protrudes outside the furnace. It is made up of the crown, sidewall and corner block. The crown and corner blocks of the feeder port is easily damaged.
Its sidewall block adopts fused cast AZS, the same refractory with the sidewall of the melting zone.
Since the feeder port does not have breast wall, its crown is lower than that of the melting zone. The crown is subjected to the impact of the flame and erosion by the dust. Fused cast AZS block with good corrosion resistance is used here.
The corner block is subjected to high temperature, molten glass, chemical attack, and the thrust of the feeding machine. Fused cast AZS block 41# WS is used here and should be processed into round or hexagonal shape to reduce the hindrance. It should be thicker than the sidewall block to increase its weight and prevent the movement of the blocks. It should be cooled by air since it is heated in two sides and the heat dissipation area is small here.
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..
The feeder port consists of feeder pool and the front wall. It is subjected to the corrosion by molten glass, erosion by the batch materials and dust, wear by the liquid and the impact of the flame.
The front wall usually adopts L-shaped block. Fused mullite block or AZS block is used. Its outside is insulated with ceramic fiber blanket.
The feeder pool is a rectangular pool that protrudes outside the furnace. It is made up of the crown, sidewall and corner block. The crown and corner blocks of the feeder port is easily damaged.
Its sidewall block adopts fused cast AZS, the same refractory with the sidewall of the melting zone.
Since the feeder port does not have breast wall, its crown is lower than that of the melting zone. The crown is subjected to the impact of the flame and erosion by the dust. Fused cast AZS block with good corrosion resistance is used here.
The corner block is subjected to high temperature, molten glass, chemical attack, and the thrust of the feeding machine. Fused cast AZS block 41# WS is used here and should be processed into round or hexagonal shape to reduce the hindrance. It should be thicker than the sidewall block to increase its weight and prevent the movement of the blocks. It should be cooled by air since it is heated in two sides and the heat dissipation area is small here.
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..
Tuesday, August 25, 2015
Corrosion And Erosion Wear Of Fused Cast AZS In Glass Furnaces
Nowadays, refractory materials are important in the glass furnace. Refractory materials are considered mechanically and chemically high performance at temperatures above 1400℃. The requirements for refractory materials are good physical and mechanical resistance to thermal shock and to attack by molten glass.
The refractory materials for the glass industry has made significant progress. Refractories for glass furnaces are normally based on A12O3, ZrO2, and SiO2, with or without Cr2O3. Refractories for the glass furnace are expected to have higher corrosion resistance to molten glass, no defects in glass environmental compatibility, reliable properties and improved methodology to identify origins of defects.
The major objective in the glass furnace is to optimize the entire process by reducing the maximum temperature of melting, improving refractory performance and/or improving fuel efficiency. The required physical and chemical properties of refractories are: thermal shock resistance, corrosion resistance, controlled expansion behavior, low thermal conductivity, and adequate creep resistance.
The fused cast manufacturing process was introduced by Fulcher in 1925 based on research conducted at Corning Glass Co. A characteristic of this manufacturing is that the materials have a low porosity. It is of great importance to the refractory, since this minimizes the glass refractory interface. Because the ZrO2 has a high melting point and has good corrosion resistance to the molten glass, fused cast AZS is widely used in the production of glass.
Fused cast AZS block generally consists of 33-41% zirconia crystals, interlocked with corundum, and minor interstitial glass. They perform well in contact with many glasses melted at 1500℃ or lower. But it can react with new developmental glasses, particularly rare earth alumino-silicates which has much higher melting temperatures, resulting in erosion of crystalline particles which cause stones in the glass.
The chemical reactions at the surfaces of refractories may take place between molten slag, fluxing agents, and gaseous substances. The corrosion of the refractories may be due to batch carryover, volatile fluxes, and melt attack, mainly at the metal line. Erosion often follows the initial corrosion, washing away refractory grains after the original bond has dissolved.
Fused cast AZS in contact with molten glass form a viscous silicate layer adjacent to the refractory thus restricting contact, and therefore, increasing corrosion resistance. When fused cast AZS are used in superstructures, they are exposed to high temperature combustion products. Superstructure and crown refractories are subjected to corrosive reactions with the vapor species of the batch components and batch carryover. In the melting of soda-lime glasses, the vapor species are primarily soda and sodium sulfates, while for borosilicate glasses, they are Na-tetraborate and B2O 3 predominate.
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..
The refractory materials for the glass industry has made significant progress. Refractories for glass furnaces are normally based on A12O3, ZrO2, and SiO2, with or without Cr2O3. Refractories for the glass furnace are expected to have higher corrosion resistance to molten glass, no defects in glass environmental compatibility, reliable properties and improved methodology to identify origins of defects.
The major objective in the glass furnace is to optimize the entire process by reducing the maximum temperature of melting, improving refractory performance and/or improving fuel efficiency. The required physical and chemical properties of refractories are: thermal shock resistance, corrosion resistance, controlled expansion behavior, low thermal conductivity, and adequate creep resistance.
The fused cast manufacturing process was introduced by Fulcher in 1925 based on research conducted at Corning Glass Co. A characteristic of this manufacturing is that the materials have a low porosity. It is of great importance to the refractory, since this minimizes the glass refractory interface. Because the ZrO2 has a high melting point and has good corrosion resistance to the molten glass, fused cast AZS is widely used in the production of glass.
Fused cast AZS block generally consists of 33-41% zirconia crystals, interlocked with corundum, and minor interstitial glass. They perform well in contact with many glasses melted at 1500℃ or lower. But it can react with new developmental glasses, particularly rare earth alumino-silicates which has much higher melting temperatures, resulting in erosion of crystalline particles which cause stones in the glass.
The chemical reactions at the surfaces of refractories may take place between molten slag, fluxing agents, and gaseous substances. The corrosion of the refractories may be due to batch carryover, volatile fluxes, and melt attack, mainly at the metal line. Erosion often follows the initial corrosion, washing away refractory grains after the original bond has dissolved.
Fused cast AZS in contact with molten glass form a viscous silicate layer adjacent to the refractory thus restricting contact, and therefore, increasing corrosion resistance. When fused cast AZS are used in superstructures, they are exposed to high temperature combustion products. Superstructure and crown refractories are subjected to corrosive reactions with the vapor species of the batch components and batch carryover. In the melting of soda-lime glasses, the vapor species are primarily soda and sodium sulfates, while for borosilicate glasses, they are Na-tetraborate and B2O 3 predominate.
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..
Monday, August 24, 2015
Suggestions On The Proper Use Of Fused Cast AZS
Based on the campaign life of the glass furnace, the indicators of the furnace operation and the physical and chemical properties and performance of fused cast AZS block, some reasonable suggestions are made on the proper use of the fused cast AZS.
Fused cast AZS is characterized with stable and dense structure and good corrosion resistance to glass. During 900-1200℃, it will have a abnormal volume expansion due to its crystal phase transition.
For structures constructed with fused cast AZS and silica brick (such as the front wall of the feeder pool), each material should have its own structure, because they have different volume changes at high temperature. For the superstructure that is less than 8m, there is no need to leave expansion joints. For the superstructure that is longer than 8m, it is recommended to divide it into several parts by expansion joints(4-6mm).
There are masonry joints between the sidewall block and the bottom block. When the refractory materials are heated, 4-5mm volume expansion per meter will be expanded into the masonry joints.
Fused cast AZS block has a higher thermal conductivity. When used in the sidewall, it parts near the liquid level require bigger cooling air flow.
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 AZS is characterized with stable and dense structure and good corrosion resistance to glass. During 900-1200℃, it will have a abnormal volume expansion due to its crystal phase transition.
For structures constructed with fused cast AZS and silica brick (such as the front wall of the feeder pool), each material should have its own structure, because they have different volume changes at high temperature. For the superstructure that is less than 8m, there is no need to leave expansion joints. For the superstructure that is longer than 8m, it is recommended to divide it into several parts by expansion joints(4-6mm).
There are masonry joints between the sidewall block and the bottom block. When the refractory materials are heated, 4-5mm volume expansion per meter will be expanded into the masonry joints.
Fused cast AZS block has a higher thermal conductivity. When used in the sidewall, it parts near the liquid level require bigger cooling air flow.
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..
Friday, August 21, 2015
New Types of Refractory For The Glass Furnace
The need of the glass manufacturers to maintain and improve the quality of glass and expand the service life of the glass furnace and the impact and influence of the oxygen-fuel combustion technology, promote the improvement of refractories and development of the new refractories.
Fused cast alumina block has been widely used in the crown of the oxygen-fuel furnace, especially when manufacturing high quality glass. Before the application of the oxygen-fuel combustion technology, only β alumina block is used in the superstructure of the melting furnace. Now both β fused cast alumina block and α-β fused cast alumina block can be used in the crown of the oxygen-fuel furnace for producing TV glass, float glass and borosilicate glass.
Fused cast AZS block has been successfully used in the crown for many years. It can be used at 1600℃ or 1650℃ and can withstand the cycle of cooling and heating well. Compared to fused cast AZS, fused cast alumina block can be used at 1700℃ and has better mechanical strength and thermal stability.
In the past, high chromium brick was mainly used for the production of reinforced glass and sometimes in the insulation glass furnace. Now it is increasingly used in some soda-lime glass furnaces. It has much better corrosion resistance to glass and can prolong the service life of throat. Besides the throat, it is also used in the end wall, the angle brick of the feeder port. However, the chromium may color the glass liquid, thus it can not be used in the white glass furnace. It was primarily used in the colored glass furnace, but now it has been successfully used in the transparent container glass furnace.
Low glass phase fused cast AZS block has been successfully used in the superstructure. The development of the oxygen-fuel combustion technology makes it find wider application in the superstructure. Since it contains a low amount of glass phase, it has better creep resistance and the amount of exuded glass phase has been reduced to a very low level.
Fused cast high zirconia block is a new type of refractory, mainly used in the glass contact areas in high quality glass furnace. It has a low potential of causing stones, knots and bubbles and can effectively reduce glass defects. It is also in some low alkali glass or hard borosilicate glass furnaces.
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 alumina block has been widely used in the crown of the oxygen-fuel furnace, especially when manufacturing high quality glass. Before the application of the oxygen-fuel combustion technology, only β alumina block is used in the superstructure of the melting furnace. Now both β fused cast alumina block and α-β fused cast alumina block can be used in the crown of the oxygen-fuel furnace for producing TV glass, float glass and borosilicate glass.
Fused cast AZS block has been successfully used in the crown for many years. It can be used at 1600℃ or 1650℃ and can withstand the cycle of cooling and heating well. Compared to fused cast AZS, fused cast alumina block can be used at 1700℃ and has better mechanical strength and thermal stability.
In the past, high chromium brick was mainly used for the production of reinforced glass and sometimes in the insulation glass furnace. Now it is increasingly used in some soda-lime glass furnaces. It has much better corrosion resistance to glass and can prolong the service life of throat. Besides the throat, it is also used in the end wall, the angle brick of the feeder port. However, the chromium may color the glass liquid, thus it can not be used in the white glass furnace. It was primarily used in the colored glass furnace, but now it has been successfully used in the transparent container glass furnace.
Low glass phase fused cast AZS block has been successfully used in the superstructure. The development of the oxygen-fuel combustion technology makes it find wider application in the superstructure. Since it contains a low amount of glass phase, it has better creep resistance and the amount of exuded glass phase has been reduced to a very low level.
Fused cast high zirconia block is a new type of refractory, mainly used in the glass contact areas in high quality glass furnace. It has a low potential of causing stones, knots and bubbles and can effectively reduce glass defects. It is also in some low alkali glass or hard borosilicate glass furnaces.
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..
Wednesday, August 19, 2015
How To Avoid The Cracking Of Fused Cast AZS Block
The quality of fused cast AZS block is related to many factors such as the chemical composition of raw materials, the melting process, the casting process and the annealing process. One of the main quality problems of the fused cast AZS block is cracking.
Fused cast AZS block is mainly composed of baddeleyite, corundum, and a small amount of mullite, glass phase and pores. When the Al2O3 content of the raw materials exceeds 30%, the raw materials is difficult to melt and the cracking rate will increase. So before feeding the raw materials into the furnaces, the Al2O3 content must be measured to ensure it does not exceed 30%.
The way of feeding will directly affect the melting. Once feeding all the raw materials may cause incomplete melting and the products will be easy to crack. Feeding small quantities repeatedly is better.
If the melting temperature is too high or low, the cracking rate will increase too. Melting the raw materials at the melting temperature and then increasing the temperature can reduce the cracking rate.
In order to reduce the residual thermal stress and avoid crack, there should be a certain amount of glass phase in the fused cast AZS to absorb the thermal stress. However, the glass phase is the weak point for the corrosion resistance of fused cast AZS. During the corrosion process, the glass phase is exuded first and replaced with the high temperature molten glass. Bubbles are released accompanying the exudation of the glass phase and pollute the glass. Fused cast AZS block (33#, 36# and 41#) contains 14-20% glass phase, thus the glass phase content has a big effect on its quality.
During the casting process, if the casting temperature is too high, the shrinkage rate and the temperature difference between the inside and outside increase and the products are easy to crack. Before casting, stop heating for 3-5 minutes to cool the molten glass to the casting temperature and then cast, which can greatly reduce the cracking rate.
During the annealing and cooling process, the casting products should be put in the insulating box. The initial temperature should not be too low. Then cool the products slowly. The crack rate can be reduced.
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 AZS block is mainly composed of baddeleyite, corundum, and a small amount of mullite, glass phase and pores. When the Al2O3 content of the raw materials exceeds 30%, the raw materials is difficult to melt and the cracking rate will increase. So before feeding the raw materials into the furnaces, the Al2O3 content must be measured to ensure it does not exceed 30%.
The way of feeding will directly affect the melting. Once feeding all the raw materials may cause incomplete melting and the products will be easy to crack. Feeding small quantities repeatedly is better.
If the melting temperature is too high or low, the cracking rate will increase too. Melting the raw materials at the melting temperature and then increasing the temperature can reduce the cracking rate.
In order to reduce the residual thermal stress and avoid crack, there should be a certain amount of glass phase in the fused cast AZS to absorb the thermal stress. However, the glass phase is the weak point for the corrosion resistance of fused cast AZS. During the corrosion process, the glass phase is exuded first and replaced with the high temperature molten glass. Bubbles are released accompanying the exudation of the glass phase and pollute the glass. Fused cast AZS block (33#, 36# and 41#) contains 14-20% glass phase, thus the glass phase content has a big effect on its quality.
During the casting process, if the casting temperature is too high, the shrinkage rate and the temperature difference between the inside and outside increase and the products are easy to crack. Before casting, stop heating for 3-5 minutes to cool the molten glass to the casting temperature and then cast, which can greatly reduce the cracking rate.
During the annealing and cooling process, the casting products should be put in the insulating box. The initial temperature should not be too low. Then cool the products slowly. The crack rate can be reduced.
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..
Tuesday, August 18, 2015
Refractory Selection For the Soda Lime Glass Forehearth
After the glass is melted in the furnace it is further conditioned and transferred to the forming section by a set of narrow channelas called the forehearth. Each forehearth has a superstructure which divides the channels into side channels and a central channel.
Channels work at constant temperature, thus thermal and chemical stresses, the temperature level and the glass corrosion at the operation temperature must be considered.
The temperature is the first factor to consider since it is limiting the application of some refractories. The glass corrosion is, actually, related to the temperature and this is why it is necessary to fix the temperature limit of the refractories (classification temperature) and choose the right ones for not reducing the normal campaign life.
Under 1270℃, high alumina (98-99 % Al2O3) sintered products in contact with glass are used, while at 1320 - 1330℃, zircon mullite bricks can be used. Zircon mullite brick is more resistant to glass corrosion than high alumina brick due to its particular crystal structure. If the operation temperature exceeds the above mentioned limits, fused cast AZS block must be used.
When glass is in contact with any refractory material at high temperature, the chemical reaction is a dissolution process. To increase the glass corrosion resistance, channels must obviously have the right porosity and density, but the crystal structure, especially the glassy phase content, is the most important factor.
The glassy phase content must be as low as possible because it is a weak point in a refractory material and to reduce it, clay must be definitely avoided. Alkali, infiltrating into the refractory during operation, react in particular with the glassy phase reducing its viscosity. Glassy phase exudes and carries away also the crystalline parts (zircon, zircon oxide, alumina) corroding and weakening the channel blocks. In short sintered refractories in contact with glass must have a crystalline structure and a very low glassy phase content for a strong glass corrosion resistance.
The operating factors of the forehearth superstructures are thermal, chemical and thermal stresses.The suitable refractories for high performances forehearth superstructures must have a low glassy phase content to resist both to vapor attacks and to creep.
Superstructure blocks are subjected to strong compression at high temperature and thus they must have high creep values. Creep is influenced by the content of low melting agents, which form the glassy phase, and this is why clay, carrying fluxing agents as sodium and potassium, must be avoided. Sillimanite brick is recommended here.
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..
Channels work at constant temperature, thus thermal and chemical stresses, the temperature level and the glass corrosion at the operation temperature must be considered.
The temperature is the first factor to consider since it is limiting the application of some refractories. The glass corrosion is, actually, related to the temperature and this is why it is necessary to fix the temperature limit of the refractories (classification temperature) and choose the right ones for not reducing the normal campaign life.
Under 1270℃, high alumina (98-99 % Al2O3) sintered products in contact with glass are used, while at 1320 - 1330℃, zircon mullite bricks can be used. Zircon mullite brick is more resistant to glass corrosion than high alumina brick due to its particular crystal structure. If the operation temperature exceeds the above mentioned limits, fused cast AZS block must be used.
When glass is in contact with any refractory material at high temperature, the chemical reaction is a dissolution process. To increase the glass corrosion resistance, channels must obviously have the right porosity and density, but the crystal structure, especially the glassy phase content, is the most important factor.
The glassy phase content must be as low as possible because it is a weak point in a refractory material and to reduce it, clay must be definitely avoided. Alkali, infiltrating into the refractory during operation, react in particular with the glassy phase reducing its viscosity. Glassy phase exudes and carries away also the crystalline parts (zircon, zircon oxide, alumina) corroding and weakening the channel blocks. In short sintered refractories in contact with glass must have a crystalline structure and a very low glassy phase content for a strong glass corrosion resistance.
The operating factors of the forehearth superstructures are thermal, chemical and thermal stresses.The suitable refractories for high performances forehearth superstructures must have a low glassy phase content to resist both to vapor attacks and to creep.
Superstructure blocks are subjected to strong compression at high temperature and thus they must have high creep values. Creep is influenced by the content of low melting agents, which form the glassy phase, and this is why clay, carrying fluxing agents as sodium and potassium, must be avoided. Sillimanite brick is recommended here.
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..
Tuesday, August 11, 2015
Masonry Of Large Sidewall Block In The Float Glass Furnaces
With the improvement of the quality of the fused cast AZS, the traditional masonry method of the sidewall brick in the float glass furnace is replaced by the large sidewall block made of fused cast AZS 33# QX.
The use of large sidewall block of fused cast AZS 33# QX eliminates the horizontal mortar joints, expands the service life of the sidewall blocks, reduces the pollution to glass liquid and improves the quality of glass. When installing the large sidewall block, the following guideline should be followed.
Since the large sidewall block is very heavy, it is better to increase the times of loading and unloading. When transporting, be gentle to avoid damages.
When installing the sidewall block, the bottom block should be even. The nozzle of the large sidewall block of fused cast AZS 33# QX should be placed towards the outside of the bottom of the sidewall.
When preheating the furnace, follow the temperature curve strictly and avoid big temperature fluctuation. Especially at 800-1200℃, the fused cast AZS block expands rapidly. Big temperature fluctuation will cause stress inside the block and may cause cracks.
During the operation, reduce the fluctuation of the level of the glass liquid since it is one of the main reason for the corrosion and erosion of the sidewall block, especially the part around the liquid level where is the junction of the solid, liquid and gas.
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, 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..
The use of large sidewall block of fused cast AZS 33# QX eliminates the horizontal mortar joints, expands the service life of the sidewall blocks, reduces the pollution to glass liquid and improves the quality of glass. When installing the large sidewall block, the following guideline should be followed.
Since the large sidewall block is very heavy, it is better to increase the times of loading and unloading. When transporting, be gentle to avoid damages.
When installing the sidewall block, the bottom block should be even. The nozzle of the large sidewall block of fused cast AZS 33# QX should be placed towards the outside of the bottom of the sidewall.
When preheating the furnace, follow the temperature curve strictly and avoid big temperature fluctuation. Especially at 800-1200℃, the fused cast AZS block expands rapidly. Big temperature fluctuation will cause stress inside the block and may cause cracks.
During the operation, reduce the fluctuation of the level of the glass liquid since it is one of the main reason for the corrosion and erosion of the sidewall block, especially the part around the liquid level where is the junction of the solid, liquid and gas.
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, 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..
Monday, August 3, 2015
Four Ways for Fused Cast AZS Casting
Casting is a manufacturing process by which the melt is poured into a mold to be solidified. 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 ways of fused cast AZS casting, including normal casting(PT), Tilt casting(QX), Reinforced casting(ZWS) and Void-free casting(WS).
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 fused cast AZS block is generally used in the sidewall of glass furnaces.
ZWS fused cast AZS block is always used in the sidewall of glass furnaces.
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.
There are 4 ways of fused cast AZS casting, 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.
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