Application and Configuration of Steel Fiber Refractory Castables

In the refractory industry, it is well known that steel fiber castables are prepared by adding stainless steel heat-resistant fibers. In addition to the conventional high-temperature abrasion resistance, the product has a certain amount of heat-resistant stainless steel fiber added to its ingredients to prevent the difference between the aggregate and the matrix in the material at high temperatures.

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Steel Fiber Refractory Castables Sales

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Characteristics of Steel Fiber Castable

  • (1) Steel fiber strengthens the tensile and flexural strength of refractory castables.
  • (2) Castables of the same material. Castables reinforced with steel fiber will drop corners after 19 cycles of water cooling at 1100°C, while castables without steel fiber reinforcement will drop corners after 14 cycles. Excellent, which proves that steel fiber reinforcement can improve the thermal shock resistance of the castable.
  • (3) Steel fiber reinforced refractory castables can still bear the load even after cracking, thereby improving the fracture resistance of the castable and increasing the strength of the refractory castable.

The Main Application of Steel Fiber Castable

Which furnace parts are suitable for steel fiber refractory castables? Refractory manufacturers have compiled the following furnace parts for your reference.

Steel fiber reinforced castable is made of special grade bauxite clinker as aggregate, and high-quality bauxite clinker and corundum fine powder as matrix. It is made of superfine powder and other composite materials as binders and additives, plus stainless steel heat-resistant fibers. At the same time, due to the addition of steel fibers, the overall strength of the furnace wall is greatly enhanced after the material is poured. Steel fiber castables are mainly used in the following areas:

  1. The inner lining of various thermal equipment.
  2. The flue, heat insulation in the large-diameter metal chimney.
  3. Industrial boiler lining, the effect is more obvious when used on the top of the furnace.
  4. Low-temperature air (≤1200℃) heat insulation in the pipeline.
  5. KT-J anti-carburizing fiber castable is used for muffle-free carburizing furnace lining.
  6. Various general and special-shaped prefabs can meet the special application requirements of users.
  7. Backing insulation layer (including furnace wall and furnace roof) with a variety of low-temperature furnace interface temperature ≤1050℃.
  8. In industrial furnaces with flat flame burners, the roof of the furnace is sealed and insulated, and the sealing effect is better than any other materials.
  9. Resistance furnace lining with task temperature ≤1200℃, the electric heating element can be exposed, and it can also be made into an embedded structure.
  10. There is no mechanical vibration in the task, and the furnace lining with large temperature changes is especially suitable. Such as bell-type furnace, removable aluminum melting furnace cover, etc.
  11. HS-J ultra-low temperature refractory fiber castable, ML-J polycrystalline mullite fiber castable, L80-J alumina fiber castable. It can be used for the lining of industrial furnaces with a task temperature of 1300-1450°C.
  12. All kinds of fuel furnace lining with task temperature ≤ 1250℃, including furnace wall and roof. Different types of refractory fiber castables are used to make composite furnace linings, with fluctuating structure, economical and reasonable, and convenient construction.
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RS Steel Fiber Refractory Castable Manufacturer

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Performance and Formula of Steel Fiber Refractory Castable

The heat-resistant steel fiber used for common steel fiber refractory castables should be selected according to the use conditions of thermal equipment, and the appropriate amount should be determined. The preparation process as follows. First, weigh the refractory aggregates, powders, binders, and additives, dry mix 1mim, and then mix with water and wet, and evenly sprinkle the steel fibers into the material without forming agglomerates. After mixing for 1 min, the material can be discharged. The total mixing time shall not be less than 5 minutes. When vibrating rods are used for molding, the vibration direction should be staggered, so that the steel fiber distribution direction is reasonable and performance can be improved.

Items 1 2 3 4 5
Chemical Composition / % Al2O3 65 90 74 68 84
MgO 4.4
CaO 1.4 3.2 1.5 1.2 2.0
Compressive Strength / MPa 1d 10 15 14
110℃ 14 69 40 49 150
1000℃ 40 70 74
1500℃ 43 91 76 80 150
Flexural Strength / MPa 110℃ 6 11 5 6
1000℃ 12 11 12 19
1500℃ 13 21 13 13 23
High-Temperature Flexural Strength / MPa 1400℃ 2.1 9.6 2.4 2.8
Line Changes after Burning 1000℃ -0.10 +0.08 -0.02 ±0.1
1500℃ +0.22 +0.62 +0.30 +0.10
Refractoriness / ℃ 1770 1830 >1790 >1790 >1790
Bulk Density / g/cm3 2.38 3.26 2.60 2.62 2.90

The above table shows the performance of a certain steel fiber refractory castable.

No. 1 is high-strength clay combined with refractory castable. The refractory aggregate and powder are made of third-grade and first-grade bauxite clinker respectively. In order to improve the performance of the matrix, fused brown corundum powder is added, and active SiO2 ultrafine powder and additives are added. Use CA-50 cement as coagulant.

No. 2 is fused calcium aluminate cement aluminum-magnesium refractory castable, dense fused corundum is aggregate, alumina and high-purity sintered magnesia powder are used as refractory powder, and superfine powder and compound additives are added at the same time.

No. 3 and No. 4 are low cement bauxite-mullite refractory castables, and refractory aggregates are made of first-grade bauxite clinker and mullite. The refractory powder is super-grade bauxite clinker powder or corundum powder, the binder is CA-70 cement, and superfine powder and composite admixtures are added at the same time.

No. 5 is a low cement, special alumina corundum refractory castable with a small number of additives. This type of high-quality refractory castable is used at higher temperatures, so the grade 330 heat-resistant steel fiber is selected. The equivalent diameter is 0.5mm, the length is 20mm, and the dosage is 2%. The water consumption is 6% ~7%. According to the selected mixing ratio, various raw materials are weighed and formed after kneading. After molding, it should be naturally cured and no water should be sprayed. After 24 hours of curing, remove the mold and continue natural curing for another 48 hours to check the performance.

With the development of unshaped refractory castables, prefabricated products of steel fiber refractory castables are also used in kiln parts. The information on this will be sorted out before sharing it with you.

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How to Solve the Phenomenon on the Surface of Refractory Castables Preforms

Unshaped refractory castables and castable preforms have been widely used by more and more high-temperature industrial kilns due to their advantages of convenient, fast construction and low labor intensity. However, many enterprise users have found that refractory castables or preforms have found some abnormal phenomena during storage or maintenance, such as chalking, white hairs, and so on. So, how to solve the white hair and chalking on the surface of refractory castables preforms?

Firstly, let’s understand how these phenomena are formed.

In fact, these are caused by the contact of high-alumina cement hydration products in refractory castables with acid gases in the atmosphere. As the moisture in the castable evaporates, salt substances continue to migrate and precipitate to the surface, and then slowly aggravate the damage process of the refractory castable. We will analyze these phenomena today. Pulverization occurs during the storage of preforms made of cement-containing refractory castables. Some of them grow “white hair” on the surface, commonly known as white alkali, which causes the pulverization of the surface of the castable. In severe cases, the strength of the castable decreases.

White-Hair and Chalking on the Surface of Refractory Castables and Preforms
White-Hair and Chalking on the Surface of Refractory Castables Preforms

Several Phenomena on the Surface of Refractory Castables after Construction

Carbonation of Castables

Carbonation of high-alumina refractory castables is often considered to be one of the main reasons that lead to the decrease of castable structure and spalling. The high-alumina cement-bonded refractory castable is exposed to the air, and the hydration products therein react with the CO2 gas in the air to undergo a carbonation reaction. In addition, refractory castables are more likely to undergo carbonation under high humidity conditions and compared with dense castables, lightweight castables with high water content are easier to pulverize. This shows that in the presence of water, the hydration product interacts with the CO2 acid gas, and the PH value of the liquid in the single pore of the phase drops sharply, which makes all the new hydration organisms in the refractory castable become unstable.

Sulfation of Castables

Compared with the carbonation of high-alumina cement hydration products, the sulfation phenomenon has not attracted enough attention from the construction party and the user. In the atmosphere, in addition to the CO2 acid gas, there are also SO2, H2S, and other gases, which also have a strong corrosive effect on the hydration products of the matrix part of the high alumina cement castable. Eventually, this lead to powdering and peeling of the castable.

In addition to being sulphated by SO2 and H2S in the air, high-alumina cement hydrate may also interact with SO42- or H+ in the water source. As the activity and acidity of the two increase, the stability of the three high-alumina cement hydration products also decreases sharply.

Salt Precipitation Phenomenon of Castable

The salt precipitation phenomenon on the surface of refractory castables is another important factor that aggravates the structural damage of the castables. During the curing or natural drying process of refractory castable, some soluble carbonate, sulfate, chloride, phosphate, and other salt compounds will focus on the surface of refractory castable and crystallize with the evaporation of water. This phenomenon is often called salting out.

As the water evaporates from the surface of the refractory castable, these ions migrate and aggregate with the water molecules from the inside to the surface of the castable, or react with acid gases in the air on the surface of the castable. The salts formed after the hydrate reaction are focused on the surface. Finally, these salt compounds crystallized out due to exceeding the solubility in water.

In fact, all soluble salts containing crystal water include chloride, sulfate, carbonate, and so on. These salts all have the process of removing the crystal water, accompanied by the change of crystal form and volume change. These are some of the reasons that aggravate the pulverization, peeling, and lumps of the surface structure when the castable is cured in the air.

Solutions to the Phenomenon after the Construction of Refractory Castables and Preforms

  • (1) Dry the castable as soon as possible after construction to remove water and eliminate the carrier of sodium salt in the cast, so that the alkali stays in the construction body and no longer migrates to the surface.
  • (2) If the construction conditions cannot be dried in time, the pouring material should be sealed and the surface should be covered with plastic film to prevent moisture from migrating to the surface with alkali.
  • (3) The refractory castable is made of refractory raw materials with low alkali content to increase the viscosity and fast hardening of the refractory castable. It can reduce the migration speed of sodium salt, strengthen quality management, and strictly control the amount of water added to the construction.
Rongsheng Refractory Castable Manufacturer
Rongsheng Refractory Castable Manufacturer

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Rongsheng Refractory Castable Manufacturer

Rongsheng is a refractory manufacturer with an environmentally-friendly and advanced unshaped refractory production line. Rongsheng’s unshaped refractory production line has an annual output of 80,000 tons. Our refractory products have been sold to more than 60 countries and regions all over the world. Our customers of refractory castables have a high degree of recognition of our product quality and a high rate of return orders. Our monolithic refractory products can be customized according to the customer’s specific furnace requirements. We have rich experience in the field of wear-resistant refractory castables and refractory plastic products. In addition, he has rich experience in prefabricated refractory castables on the roof of the furnace. For more information about monolithic refractories, please contact us.

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Performance Requirements of Al2O3-MgO·Al2O3 Refractory Castables for Steel Ladle

Ladle castables are used in steelmaking plants and foundries to receive molten steel and carry outpouring operations in front of open-hearth, electric furnace, or converter. Ladle castable is a kind of granular and powdery material made of refractory materials and a certain amount of binder for a ladle. Ladle castable is an unshaped refractory made of high alumina bauxite, corundum, and magnesia as the main materials, using composite micro powder and adding some additives.

Steel Ladle Castable
Steel Ladle Castable

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Ladle castables are made of bauxite clinker, corundum, magnesia, magnesium spinel, and ultrafine powder, etc., with different binders and additives. Its characteristics are strong corrosion resistance, good thermal shock resistance, good volume stability, suitable for medium and small ladle use, and long life. Good explosion-proof performance, high-temperature strength, slag corrosion resistance, and strong erosion resistance.

Al2O3-MgO·Al2O3 Refractory Material for Ladle

Al2O3-MgO·Al2O3 refractory materials are selected for the sidewalls and bottom of the ladle. The most common form is Al2O3-MgO·Al2O3 castables. The design of its chemical composition is mainly to use the eutectic phase region of the MgO·Al2O3-Al2O3 sub-system in the Al2O3-MgO binary system, and the area of MgO about 5%. As shown in Figure 5-26, its Al2O3 content is about 90%.

This castable not only has good corrosion resistance (see Figure 5-27), but also has excellent resistance to slag penetration, as shown in Figure 5-28 and Figure 5-29. Figures 5-27 and 5-29 show that the more spinel is added, the more spinel with high MgO content is added, the better the corrosion resistance. The resistance to slag penetration is preferably 90% Al2O3 spinel castable. This type of Al2O3-MgO-Al2O3 castable has a thin slag layer and fewer nodules during use, which protects the inner refractory material. Therefore, its durability is good.

The ω (MgO) in the spinel used in this type of Al2O3-MgO·Al2O3 castables is 10% to 30%, and ω (Al2O3) is 70% to 90%. The choice of spinel particles in castables is usually determined by test results.

The particle size of MgO·Al2O3 (20% content) has an effect on the infiltration of slag into the Al2O3-MgO·Al2O3 system. This shows that only when MgO·Al2O3 is added in the form of fine powder, the thickness of the slag soaked layer is the smallest. It can be seen that only when MgO·Al2O3 is evenly dispersed in the matrix of the Al2O3-MgO·Al2O3 brick can the slag penetrate into the deep part of the brick more effectively. The relationship between the amount of spinel added and the melt loss index and slag penetration thickness can be obtained for castables containing 10% to 30% MgO·Al2O3. The small thickness of the slag impregnated layer is an important basis for guiding the design formula.

Alumina Magnesia Refractory Castable
Alumina Magnesia Refractory Castable

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When the mixing amount of spinel is below 20% (mass fraction), fine powder less than 1mm is used. Under this condition, when the amount of spinel added increases, it has the effect of inhibiting slag penetration. When the amount of spinel is greater than 30% (mass fraction), particles larger than 1mm are used. Under these conditions, when the amount of spinel added increases, it has the effect of improving corrosion resistance. The damage of the castable due to structural spalling is much greater than that of Al2O3-C bricks, and the damage rate of the former is 1.3 to 2.5 times that of the latter. Compared with Al2O3-C bricks, the damage rate of castables is reduced by about 30%, showing better results.

At the most severely damaged ladle impact location, the damage rate of Al2O3-C bricks increases with the increase in the ratio of stainless steel to steel. Castable C has the same damage rate and service life as Al2O3-C bricks. When the Al2O3-MgO-Al2O3 series castable containing 20% spinel fine powder is applied to the sidewall of the ladle and the impact part of molten steel, it will not produce cracks and peeling damage during use, and has the characteristics of stability and durability.

The above research results show that the amount of spinel added has an important impact on the performance of aluminum-spinel fired bricks. This kind of fired brick also has the problem that the joints of the bricks are corroded first. To this end, a certain amount of fused magnesia particles can be added to the ingredients to cause residual linear expansion during use. Therefore, the problem of the brick joints being corroded first is prevented, and the service performance of the aluminum-spinel brick can be improved.

In addition, due to the high CaO content of dolomite, it has excellent impurity purification ability. Therefore, the lining of asphalt combined with dolomite bricks is the most economical material for smelting clean steel. The other is to use fired dolomite bricks as lining to produce ultra-low carbon steel.

Alumina Magnesia Spinel Castable
Alumina Magnesia Spinel Castable

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Rongsheng Unshaped Refractory Manufacturer

Rongsheng is an experienced manufacturer of refractory materials. Rongsheng not only sells various refractory brick products to customers all over the world but also provides overall refractory material solutions and refractory materials for various thermal furnace linings. Rongsheng’s advanced fully automatic monolithic refractory production line has an annual output of 80,000 tons. Rongsheng’s best-selling products include various alumina bricks, magnesia bricks, silica bricks, corundum bricks, mullite bricks, thermal insulation bricks, and other refractory brick products. There are also monolithic refractory products such as high-aluminum refractory castables, refractory plastics, refractory ramming materials, and refractory spray coatings. We also provide customers with high-quality refractory bricks and refractory castables for ladle lining. To get the price of Rongsheng refractory materials for free, please contact us. We will provide you with refractory lining materials that best suit your production needs based on your specific furnace conditions.

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What are the Effects of Adding Silicon Carbide on Refractory Castables Properties?

Many people may wonder whether adding silicon carbide to refractory castables can increase strength? It is well known that adding silicon carbide to refractory castables can increase the strength of the castables. However, the addition of different proportions has different effects on the performance of refractory castables. What are the effects of adding silicon carbide on Refractory Castables Properties? Refractory manufacturers have come to the following conclusions by analyzing experimental data.

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Rongsheng Silicon Carbide Refractory Castables for Sale

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What Effects Does the Addition of Silicon Carbide have on the Refractory Castables Properties?

The proportion of silicon carbide added in the refractory castable is too high, which will affect the strength of the castable at medium and low temperatures. Early mulliteification is prone to occur, and the stomata will be relatively reduced. However, the compressive strength of refractory castables increases at high temperatures.

If too little or no silicon carbide is added to the refractory castable, the strength of the castable will decrease by 25%. The current silicon carbide castable is actually a high-strength high-aluminum castable with few silicon carbides. Therefore, the high aluminum castable strength maintained by the castable without silicon carbide.

High-Strength High-Alumina Refractory Castables
High-Strength High-Alumina Refractory Castables

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The addition of silicon carbide to the refractory castable is too low, then it will not play the role of increasing the compressive strength of wear resistance. At this time, judging from its performance, it is just a high-aluminum castable. However, under certain conditions of severe lining erosion, it is still necessary to add silicon carbide to the high-aluminum castable to change the properties of the castable. In order to improve the thermal shock stability and wear resistance coefficient of the refractory castable, the service life of the lining is longer.

Of course, excessive addition of silicon carbide in the refractory castable will react with silicon dioxide, and too little addition will have no effect. How to balance it? Generally, when the furnace is not severely eroded and the erosion is not severe, add 6% silicon carbide to the refractory castable. It is the best balance ratio to use in the strength of semi-finished products or high-temperature areas.

The effect of the amount of silicon carbide added on the apparent porosity of the castable. With the increase in the amount of silicon carbide added, the apparent porosity gradually decreases after heat treatment at 1400 ℃. This shows that as the liquid SiO2 on the surface of silicon carbide increases, more closed pores are formed. At high temperatures, the apparent pores are continuously reduced, and the degree of densification will increase.

The effect of the amount of silicon carbide added on the linear change rate of refractory castables. With the increase of the amount of silicon carbide powder added, the linear rate of heat treatment at 1400℃ gradually decreases. The main reason is that the surface of silicon carbide is oxidized into a liquid SiO2 film at high temperature, showing a trend of increasing volume. This reaction occurs slowly from the outside to the inside, and correspondingly offsets the shrinkage of the substrate. In addition, 1100-1350 ℃ is also the formation stage of mullite. The outer layer of silicon carbide is oxidized to form liquid SiO2, which reacts with alumina powder to form staggered, acicular mullite crystal phases. Accompanied by the larger volume expansion, it compensates for part of the line shrinkage.

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Corundum Mullite Castable Supplier

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The Influence of the Amount of Silicon Carbide Added on the Refractory Castables Properties

The effect of the amount of silicon carbide added on the high-temperature flexural strength of refractory castables. The high-temperature flexural strength of the refractory castable after firing at 1400°C, with the increase of the silicon carbide content, the high-temperature flexural strength is significantly enhanced, and it is much higher than that of the castable without silicon carbide. This is a very significant feature brought by silicon carbide.

When the addition amount of silicon carbide is above 5%, it has good alkali resistance. With the increase of the added amount, the corresponding corrosion resistance and thermal shock resistance can be improved. However, adding a small amount of silicon carbide to the corundum-mullite castable has an effect on the physical properties at room temperature, high-temperature flexural strength, and microstructure. At the same time, trace silicon carbide will not significantly increase the thermal conductivity and heat loss of the castable.

In summary, increasing the content of silicon carbide from 1% to 5% can increase the strength of the refractory castable after heat treatment at 110-1500°C. However, increasing the content of silicon carbide from 5% to 9% will affect the strength of the castable after heat treatment at 1100°C. After the addition of silicon carbide, the wear resistance of the castable is hardly improved after the 110°C treatment; after the 1100°C treatment, the wear resistance of the castable with the silicon carbide content of 1% to 5% is slightly improved. However, the wear resistance of castables with SiC content of 5%-9% is worse.

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Rongsheng Refractory Castable Manufacturer

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Rongsheng Refractory Castables Manufacturer

The production of refractory castables does not go through high temperature. The reason why the amount of refractory castables is now increased and has a wide range of uses. It is because the production cycle is short and the construction is convenient and quick. The iron parts and special parts of industrial furnace lining can play a better role. Even different manufacturers of refractory castables are constantly experimenting and updating the recipes of castables according to the actual use of customers, so as to better enable the castables to exert their best performance during use. Rongsheng is a refractory castable manufacturer with rich production and sales experience. Rongsheng’s advanced unshaped refractory production line has an annual output of tons. To get the price of refractory castables for free, please contact Rongsheng refractory castable manufacturers.

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Performance Indicators of Commonly Used Refractory Castables in Cement Plants

Refractory castables in cement plants generally use high-alumina wear-resistant castables, steel fiber castables, low-cement castables, corundum castables, alkali-resistant castables, magnesia-chrome spray coatings, phosphate castables, etc. Of course, there are more high-end ones. For example, the castable for coal injection pipes uses alumina-silicon carbide series refractory castables, which is resistant to thermal shock and alkali. In addition, there are corundum-spinel castables, which have good high-temperature flexural strength and alkali resistance. Next, let’s learn more about the performance indicators of commonly used refractory castables in cement plants.

Silicon Carbide Refractory Castable
Silicon Carbide Refractory Castable

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Refractory Castable in Cement Plants for Different Parts

The preheater uses a lower temperature, and generally uses cheaper alkali-resistant castables. The decomposition furnace is prone to skinning and blocking, and anti-skinning castables are generally used. The front and back of the rotary kiln have strong erosion at the mouth of the kiln. Generally, steel fiber castables, kiln mouth castables, and corundum castables are used. The temperature of the kiln door cover is relatively high and there is cold air. Generally, high alumina and low cement castable or steel fiber castable are used. The use conditions of the coal injection pipe are the most demanding, and the special castable for the injection pipe is generally used. When choosing refractory castables for cement plants, you need to look at the life cycle of the refractory castables. No matter how the name and grade of refractory castables change, it is important to meet the production needs of cement kilns. Rongsheng refractory material production and sales manufacturer is specialized in refractory materials for the cement industry. If your cement kiln needs refractory materials, please contact us.

High strength abrasion resistant castable for sale
High strength abrasion resistant castable for sale

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High-Strength Refractory Castable

High-strength refractory castables are mainly used for parts that are easy to wear in thermal kilns, such as kiln mouths and coal injection pipes. It is formulated with corundum as aggregate, high-quality high-alumina cement as a binder, and a small number of additives. However, this kind of castable is prone to porosity during the pouring process, and it is easy to peel off during the pouring process, and strong growth is relatively slow. In the process of pouring and subsequent curing, drying, and heating, it should be more careful and delicate. JC498-92 “High-strength Alkali-resistant Castable” stipulates its main physical and chemical performance indicators as follows:

High-strength Alkali-resistant Castable Physical and Chemical Performance Indicators
Items Excellent Grade Grade I
Al2O3 (%) ≥ 93 93
SiO2 (%) ≤ 0.5 1.0
CaO (%) ≤ 4.0 4.0
Crushing Strength (MPa) ≥ 110 ℃ 80 60
1100 ℃ 100 70
1500 ℃ 120 100
Flexural Strength (MPa) ≥ 110 ℃ 8 6
1100 ℃ 9 7
1500 ℃ 10 9
Linear Change Rate (%) ≤ 1100 ℃×3h 0.5 ±0.5
1500 ℃×3h 0.5 ±0.5
Bulk Density after 110 ℃ drying (kg/m3) ≥ 2900 2900
Refractoriness (℃) ≥ 1800 1800
Note: The initial setting time is not less than 30min and not more than 240min.
Steel Fiber Reinforced Refractory Castable
Steel Fiber Reinforced Refractory Castable

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Steel Fiber Reinforced Refractory Castable

Steel fiber-reinforced refractory castables are made of high alumina bauxite clinker or corundum as aggregates and powders, adding binding agent and the appropriate amount of heat-resistant stainless steel fiber, or adding appropriate additives. The proportion of steel fiber in the clinker should be 4% (weight ratio). Steel fiber in the refractory castable greatly improves the anti-stripping performance of the refractory building material. The distribution of steel fibers has a great influence on the quality of concrete, and random distribution is better. Therefore, the time of vibrating should not be too long. The steel fiber castable must be poured at one time, otherwise, the possibility of peeling between the two layers is very high. The physical and chemical performance indicators specified in JC/T499-92 “Steel Fiber Reinforced Refractory Castables” are as follows:

Steel Fiber Reinforced Refractory Castables Physical and Chemical Performance Indicators
Items Ordinary Material High-strength Material
FA FC FHA FHC
Al2O3 (%) ≥ 70 83 70 80
Crushing Strength (MPa) ≥ 110 ℃ 70 70 70 80
1100 ℃ 40 50 70 80
Flexural Strength (MPa) ≥ 110 ℃ 9.0 9.0 10.0 12.0
1100 ℃ 5.5 6.5 10.0 12.0
Linear Change Rate (%) ≤ 1100 ℃×3h ±0.4 ±0.5 ±0.4 ±0.5

Other Refractory Castables

Common refractory castables often have a higher proportion of cement content (10%-15%, weight ratio). But this has caused a series of performance decline of the castable, the reasons are:

  1. In order to completely hydrate the cement, excessive water (10%-15%) is added during mixing, which will increase the porosity of the ceramic refractory castable and decrease the density.
  2. Calcium aluminate hydrate has a strong dehydration and recrystallization effect in the middle-temperature stage, which destroys the structure of the hard spots in the castable, and makes the strength of the refractory castable drop sharply in the middle-temperature stage.
  3. The cementitious binder brings more calcium into the castable, resulting in a decrease in the softening temperature of the ceramicist refractory castable under load and deterioration of thermal shock performance.
Low Cement Castable Refractory Material
Low Cement Castable Refractory Material

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In view of the above problems, low cement refractory castables effectively avoid the regret of high-temperature section performance. Refractory castables with a cement content of less than 8% are called low-cement refractory castables; those with a cement content of less than 4% are called ultra-low cement refractory castables. Compared with ordinary refractory castables, its structure is dense, the apparent porosity is low, the refractoriness is high, the high-temperature strength is high, the load softening temperature is high, and the thermal shock performance is good. However, due to the low cement content, the setting time is long and the early strength is low, which is particularly disadvantageous for construction in winter and low-temperature conditions.

Chinese refractory materials companies have found in experimental research that adding a small amount of inactive powder (silica fume or Al2O3) below 5 microns into the castable can fill and lubricate the refractory, and can effectively reduce water consumption and increase the castable. The masonry is dense, thereby increasing the strength and resistance to chemical erosion. The low cement refractory casting performance indicators are as follows:

Low Cement Refractory Castable Performance Indicators
Items High Alumina Low Cement Refractory Castable Corundum High-Strength Refractory Castable
GJ – 15B LC – 160 GJ – 18S C – 18S
Al2O3 (%) 70~75 75~78 ≥ 90 ≥ 93
SiO2 (%) 1.5~2.0 1.5~2.0 1.5~2.0 ≤ 0.4
CaO (%) 15~20 12~15 5~7 ≤ 0.5
Bulk Density (kg/m3) 2600 2700 3100 2880
Crushing Strength (MPa) ≥ 110 ℃ 100 100 100 80
1100 ℃ 110 110 110 80
1500 ℃ 110 110 110 100
Flexural Strength (MPa) ≥ 110 ℃ 12.0 14.0 14.0 8.0
1100 ℃ 15.0 15.0 15.0 8.0
1500 ℃ 15.0 15.0 15.0 9.0
Linear Change Rate (%) ≤ 1100 ℃×3h -0.4 -0.4 -0.4
1500 ℃×3h -0.6 ±0.5 -0.6
Maximum Use Temperature  (℃) 1500 1600 1700 1750
Reference Water Consumption (%) 5.5~6.5 5.5~6.5 5.5~6.5 7~9
Rongsheng Refractory Castable Manufacturer
Rongsheng Refractory Castable Manufacturer

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Rongsheng Refractory Castable Manufacturer

Rongsheng refractory castable manufacturer has an advanced and fully automatic unshaped refractory production line with an annual output of 80,000 tons. Rongsheng’s unshaped refractory products include high-aluminum refractory castables, wear-resistant castables, wear-resistant plastics, and anti-skinning castables. It can be applied to a variety of thermal kiln equipment, such as ladle lining, heating furnace lining, cement kiln lining, etc. It is widely used in steel, metallurgy, non-ferrous, chemical, and other industries. If you need to buy refractory castables, get the price of Refractory Castables in Cement Plants, please contact us. We will provide you with services according to your specific needs.

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Advantages and Performance Requirements of Refractory Castables

At present, with the rapid development of the refractory castable industry, the Requirements of Refractory Castables are granular powder material composed of a binder and a refractory material and has a certain specific gravity. It can be cast and has high fluidity. High-temperature castables made of refractory materials have higher cohesiveness, water content, and fluidity than other castables. In practice, the required materials and adhesives can be selected according to the conditions of use, and the lining can be directly cast, or the preform can be cast or compacted. Therefore, the application range of prefabricated blocks is wider.

Rongsheng High Alumina Refractory Castable Manufacturer
Rongsheng High Alumina Refractory Castable Manufacturer

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Operational Advantages of Refractory Castables

Refractory castables need to be operated at high temperatures during operation. High-temperature castables should have the function of not softening or melting at high temperatures. It also has an excellent load softening temperature. High-temperature castables can withstand the load in the kiln and the stress during operation, and will not lose structural strength at high temperatures, and will not soften and collapse.

When the refractory castable is used at high temperatures, its volume will change due to the physical and chemical lining inside the castable. The production and testing of refractory and high-temperature castable materials are strictly in accordance with the requirements. Professional inspectors test the quality of refractory castable layer by layer to bring you high quality.

Rongsheng Silicon Carbide Refractory Castables
Rongsheng Silicon Carbide Refractory Castables for Sale

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Classification of Refractory Castables

According to the material classification of refractory castables, refractory castables include high alumina castables, corundum castables, silicon carbide castables, clay castables, silicon castables, magnesium castables, etc. According to the main purpose, it can be divided into impervious castable and hot castable. The production cycle of high-temperature castables is usually shorter than that of refractory bricks of the same material. Therefore, the sales volume of high-temperature castables is very large.

The requirements of Refractory Castables are high formulas, reasonable particle size distribution, and the type and amount of additives have a great influence on the castables. The structure of the castable and the drying of the oven should be carried out in strict accordance with the requirements to ensure the service life of the castable. Due to a series of objective reasons, such as application environment and engineering progress, some additives or other materials can be added to the casting to meet the requirements. For example, in order to increase the strength of the castable, a certain amount of heat-resistant steel fiber can be added to the castable, or some accelerators can be added to accelerate the initial setting time of the castable.

Corundum Self-flowing Wear-resistant Castable
Corundum Self-flowing Wear-resistant Castable

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Refractory Castables with Special Properties

The special application environment makes it necessary to adjust the proportion of refractory castables to improve the performance of the castables. For example, low cement castables for furnaces. Because the performance of the castable decreases with the addition of cement, in order to meet the conditions of use, the amount of cement must be reduced. By adding modified materials to increase the strength of the castable, and prevent the decrease in the amount of cement from affecting the strength.

Self-flowing castable, also known as non-vibration castable. It not only has performance similar to low cement and ultra-low cement castables but also has rheological characteristics. Therefore, it can flow and degas without external force. Compared with vibrating castable, it has the characteristics of self-flowing and self-leveling, smooth and pumpable construction surface, short construction time, no noise, and low labor intensity. Especially suitable for pumping construction and use in thin-layer and multi-arch areas. Therefore, in recent years, it has continuously received attention at home and abroad and its use range has been continuously promoted. In the cement industry, metallurgical industry, and non-ferrous metals industry. Such as the permanent lining of the tundish, the lining of the movable fume hood for the secondary smelting below the bottom of the blast furnace, the trough induction insulation layer for cast iron, the lining of the civil waste incinerator, etc., the use effect is very good.

Low Cement Castable Refractory Material
Low Cement Castable Refractory Material

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There are many factors that affect the rheology of the castable, such as the limit size, shape, distribution, water absorption of the particles, the nature and amount of the binder and dispersant, the amount of water added, and the mixing and stirring process. But the most important influence is the combination system, particle size distribution and the nature and amount of dispersant added.

The amount of cement added has a significant effect on the fluidity of the castable. Calcium aluminate cement needs an appropriate amount of water in the process of forming hydration products. When the amount of water added is the same, the amount of cement added will inevitably reduce the amount of free water and reduce the fluidity of the castable. But if the amount of cement is too small, it will affect the strength of the castable at low temperatures. Therefore, under the premise of ensuring the strength of the castable, the amount of cement should be appropriately reduced. In ultra-low cement castables, cement mainly acts as a delayed accelerator. The research on the rheological properties of corundum spinel-calcium aluminate suspension shows that with the increase of calcium aluminate cement, the yield stress and plastic viscosity of the suspension tends to increase.

Rongsheng Refractory Castable Manufacturer
Rongsheng Refractory Castable Manufacturer

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Rongsheng Refractory Castable Manufacturer

Castable is also called refractory castable, which is a kind of unshaped refractory. The manufacturer of Rongsheng refractory castables pointed out that the Requirements of Refractory Castables are easy to construct and have good integrity. They can be used for the lining of a variety of industrial kilns and can also be used to make preforms. Rongsheng’s advanced and fully automatic unshaped refractory castable production line can produce a wide variety of castables, which can be differentiated according to different dimensions. Among them, according to the characteristics, there are mainly high-strength wear-resistant castables, high-temperature castables, low-cement castables, steel fiber castables, acid-resistant, and heat-resistant castables, and other castables with characteristics. If you want to buy monolithic refractory products and know the price of monolithic refractories, please contact us. We will provide you with services according to your specific needs.

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What are the Lining of the Heating Furnace?

The heating furnace is divided into furnace, fuel system, air supply system, smoke exhaust system, and cooling system. The furnace is a space composed of the furnace wall, the furnace top, and the furnace bottom, and different pouring materials are used for each part. Let us understand the refractory materials used in the lining of the heating furnace.

Refractory Lining of the Heating Furnace
Refractory Lining of the Heating Furnace

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  1. Low-cement castables are used to wrap the structure of water beam-columns. The column tube and the lower part of the supporting beam in the furnace are all made of low cement castables. Low-cement castables are also used in the low-temperature zone of the heating furnace, flue parts, and furnace body parts that do not exceed 1300°C.
  2. Self-leveling castables are used in the heating furnace where the structure is complicated and cannot be vibrated manually. The use temperature is 1500℃, which is characterized by good thermal shock resistance, high refractoriness, easy construction, and almost no need for vibration.
  3. Phosphate castables are suitable for heating furnace bottoms and other parts that are severely affected by material friction and hot air erosion. The operating temperature is between 1000-1600°C. It is a castable with phosphoric acid or phosphate as the binder and aluminum calcium cement and magnesia as the accelerator.
  4. Mullite castable. Because mullite refractory castable has high thermal shock resistance, erosion resistance, good erosion resistance, good volume stability, and high service temperature. It is generally used in key parts such as furnace walls, furnace roofs, and press beams.
  5. Anti-dry slag castable, suitable for the bottom of the heating furnace, and the place where iron oxide slag is deposited. The use temperature can reach 1600℃. Its main characteristics are high refractoriness, good thermal shock resistance, and good resistance to the corrosion of iron oxide slag in the heating furnace.
  6. Lightweight castable, suitable for heat insulation layer of the furnace wall, furnace roof, flue, etc. High-strength lightweight castables can also be used as working linings for smoke exhaust systems and hot air ducts. It is characterized by low bulk density, good thermal stability, low thermal conductivity, and certain refractoriness.
  7. Bauxite cement castable is a castable produced by mixing various refractory aggregates and powders in a certain proportion with aluminate cement as a cementing agent. It has the characteristics of fast solidification, high strength, thermal shock resistance, and slag resistance. It not only meets the refractory performance of the heating furnace body but also improves the construction performance of the furnace body.
  8. The advantage of fire-resistant plastic is that there are no gaps in the overall construction and good airtightness. The furnace lining uses a large number of plastic materials instead of castables and is mainly used for the top of the furnace.
Low Cement Castable Refractory Material
Low Cement Castable Refractory Material

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What is the Meaning of the Refractory Castables Grades?

The various castables used for the lining of the heating furnace have been introduced above. How to make a specific distinction between them? This introduces the definition of refractory castable grades. What is the meaning of refractory castable grades? It is usually used in combination with numbers and pinyin letters to distinguish the material, performance, and purpose of the castable. Refractory castable grades have refractory standards and the settings of different castable manufacturers. Next, we will learn about the types and grades of common refractory castables.

Classification of Refractory Castables

1. Classified by material, silicon castable, clay castable, high alumina castable, mullite castable, corundum castable, aluminum-magnesium castable, etc.

2. According to the purpose, it can be divided into several types of castables for industrial furnaces, such as castables for steel rolling furnaces, castables for tapping channels, castables for mixing furnaces, and castables for cement kilns.

3. According to the bulk density, it can be divided into light castable and heavy castable.

4. According to its characteristics, it can be divided into refractory steel fiber reinforced castable, anti-skinning castable, low cement castable, high-strength castable, etc.

Mullite castable price
Mullite Refractory Castable with High-Quality

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Grades of Refractory Castables

1. Brands of silicon castables: rsg-70, rsg-60, rsg-50, etc. Among them, rs is the manufacturer of Rongsheng castables, G is the main material selected for castables is silicon, and the quantity is the silicon content.

2. Brand of castable clay: nn-45. Among them, the first n is clay as the binder, and the second n is the main material selected for the clay castable. The number is the main component content of the clay castable)

3. Grades of high-aluminum castables: nl-70, nl-60. Among them, n is clay as a binder, l is the main material selected for the castable is high aluminum material, and the quantity is the aluminum content of the high aluminum castable.

4, aluminum-magnesium castable grades: amc-70, amc-80, etc. Among them, a, m, and C are the English initials of alumina, magnesia, and castable. The number is the content of the main raw materials selected for aluminum-magnesium castables.

  1. Castable grades for steel rolling heating furnace: zj-42, zj-60, zjs-65, etc. Among them, Z is the steel rolling heating furnace, J is the castable, and s is a part of the water-cooled tube of the heating furnace. The number is the main material content selected for the castable of the steel rolling heating furnace.

6. Grades of castable for iron ditch: Asc-1, Asc-2, Asc-3. Among them, a, s, and C are the English initials of alumina, silicon carbide, and carbon. The number is only used to distinguish the castable grade.

The above is the introduction of a refractory castable brand. Hope you can understand the meaning of the casting brand after reading it. There are many brands of refractory castables, some are set by the castable manufacturers themselves, and some are set in accordance with refractory standards. No matter what way the refractory castable is named, it is to distinguish the material, grade, performance, and purpose of the refractory castable.

Rongsheng Refractory Castable Manufacturer
Rongsheng Refractory Castable Manufacturer

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Rongsheng Refractory Castables Manufacturer

Rongsheng refractory castable manufacturer has an advanced and fully automatic unshaped refractory castable production line with an annual output of 80,000 tons. Rongsheng has provided high-quality refractory castables, mullite castables, self-flowing refractory castables, wear-resistant refractory plastics, corundum mullite refractory plastics, etc. for many turnkey projects. For more information about the refractory castables Lining of the Heating Furnace, Rongsheng’s monolithic refractory products, and Rongsheng refractory manufacturers, please contact us. We will provide you with services according to your specific needs.

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How to Improve the Performance of Refractory Castables?

With the continuous progress in the production and use of refractory castables, it is necessary to improve the wear resistance and thermal shock resistance of refractory castables. The research and development of new refractory castables with excellent high-temperature strength, good thermal shock resistance, and good corrosion resistance will help improve the life of cement kiln linings. Rongsheng refractory manufacturer. There are two important measures to improve the performance of refractory castables. In this article, you can also learn another two ways to improve the performance of refractory castables.

Corundum Self-flowing Wear-resistant Castable
Rongsheng Corundum Self-flowing Wear-resistant Castable

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Improve the Wear Resistance and Thermal Shock Resistance of Refractory Castables

  1. Measures to improve the wear resistance of wear-resistant castables
  • Reduce the critical particle size of the castable. From 8mm to about 5mm.
  • Improve the flexural strength of the castable in the medium temperature and hot state. At a medium temperature of 900°C, the flexural strength of the castable indirectly reflects the wear resistance of the castable. The current development trend is to require the hot flexural strength of the castable to be no less than 20MPa.
  • Improve the bonding ability of the castable matrix. It is formulated with multi-level micro powder and super micro powder to form the tightest accumulation. Promote sintering at medium temperature and improve the bonding ability of the castable matrix.
  • Use high-hardness refractory materials as aggregates.
  1. Measures to improve thermal shock resistance of wear-resistant castables

Firstly, It adopts composite aggregate and composite powder, that is, complex phase technology. The difference between the linear expansion coefficient of aggregate and matrix is used to balance the strength and thermal shock resistance of the castable.

    •  High expansion aggregate + low expansion matrix. This combination is very resistant to thermal shock.
    •  Low expansion aggregate + low expansion matrix. This combined castable has uniform bonding and high mechanical strength. General thermal shock will not produce huge stress in the castable, and cracks will appear.

Then, Reduce the thermal expansion rate of the material. Try to choose materials with a relatively low thermal expansion rate to improve the thermal stability and mechanical impact of the castable.

Low Cement Castable Refractory Material
Low Cement Castable Refractory Material

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How to Improve the Performance of Refractory Castables?

In addition, the performance of refractory castables can also be improved according to the application characteristics of refractory materials.

Add water reducing agent to refractory castable

Seeing such topics, it is estimated that everyone is like me, the first thing that comes to mind is what is the use of refractory castables added to water-reducing agents.

The water reducing agent is added to the castable, which can significantly reduce the amount of mixing water added during the construction of the castable. In the case of constant water consumption during the construction of the castable, it can also increase the fluidity or plasticization of the castable.

Water reducing agent is an electrolyte material of surface-active substance, which is dissolved in castable and can be adsorbed on the surface of particles. By increasing the repulsive force between the ion surface and the particles in the solution, the free water which is composed of fine particles and wrapped in the castable structure is released. It plays a role in wetting and dispersing. Water reducing agents can also be called a dispersing agent.

Water reducing agent is a dispersant or flow agent of high alumina cement, which plays a plasticizing or deflocculating role in refractory castables. Under the condition of keeping the flow value of the refractory castable basically unchanged, the water reducing agent does not chemically react with the comprehensive components of the raw and auxiliary materials in the castable, nor does it generate compounds, but only plays a physical and chemical role on the surface.

Because the water reducing agent can release the free water in the castable structure. Therefore, while keeping the fluidity of the castable unchanged, the water consumption during the construction of the castable can be reduced. Or under the condition that the castable does not change the unit water consumption, increase the rheology of the castable, improve the working skills, and make the refractory castable easier to construct and shape.

Steel Fiber Refractory Castable for Sale
Steel Fiber Refractory Castable for Sale

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Add steel fiber to refractory castable

In the production of refractory castables, steel fiber refractory castable products of different diameters are added. Steel fiber is a product made of heat-resistant and wear-resistant stainless steel or other steel types. Common steel fiber specifications are 20mm, 25mm, 30mm, and 35mm. Steel fiber castable is a refractory castable with high strength, good thermal shock resistance, and good wear resistance. Adding steel fiber to the refractory castable can enhance the performance of the castable and increase the use effect.

The effects of adding steel fiber to refractory castable are:

(1) Enhance the toughness of the lining, improve the resistance to mechanical impact, and wear resistance.

(2) Improve thermal shock resistance, improve cracking, and peeling resistance.

(3) Suppress linear shrinkage after curing, drying, and heat treatment.

The refractory castable is added with steel fiber to enhance the use effect after pouring, but the amount of steel fiber added to the castable is determined according to the requirements of the technical department. Too much steel fiber added to the castable can cause damage to the lining at high temperature after pouring, reduce the corrosion resistance of the lining, and affect the performance of the kiln lining.

Rongsheng Refractory Castable Cement Manufacturer
Rongsheng Refractory Castable Cement Manufacturer

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Rongsheng Refractory Castable Manufacturer

The Rongsheng refractory castable manufacturer has an advanced and fully automatic refractory castable production line with an annual output of tons. Rongsheng is a strong refractory material manufacturer and sales company. Rongsheng has served customers in more than 60 countries around the world. For example, etc. Moreover, our refractory family R&D team is also working hard to provide customers with refractory linings that best suit their production needs. If you want to know the manufacturer of Rongsheng refractory materials or want to obtain a quotation of refractory materials, such as low cement castable, phosphate bonded castable, high alumina castable, corundum castable, etc. please contact us. We will provide you with services according to your specific needs.

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What are the Functions of Micro-Powder in Refractory Castables?

The basic mechanism of micro-powder in refractory castables is filling and lubrication. The micro powder can be used to fill the gap between aggregate and powder, reducing the amount of water used. After the molded body removes water, there are fewer holes left, which can increase the bulk density and reduce the apparent porosity. Thereby improving the structural strength of the material and optimizing material performance. In addition, the fine powder particles can form colloidal particles in water. When there is a dispersant, the particle surface forms an overlapping electric double layer to generate electrostatic repulsion, which overcomes the van der Waals force between the particles. Reduce the interface energy and prevent the particles from adsorption and aggregation. At the same time, the dispersant is adsorbed around the particles to form a solvent layer. Therefore, the fluidity of the castable is also increased, and the performance of the refractory castable material is optimized.

Silica Micro-powder in Refractory Castable
Silica Micro-powder in Refractory Castable

Micro-powder Used in Refractory Castables

In refractory castables, the most used micro powders are active SiO2 powder and a-AL2O3 powder. Followed by SiC powder, high alumina powder, white corundum powder, brown corundum powder, zircon powder, and spinel powder. The function of micro-powder in refractory castables is to fill and lubricate and increase fluidity.

The Silica Powder Added in the Refractory Castables

The SiO2 powder used in the refractory industry is mainly micron-sized. There are many types of SiO2 micro powders, among which silica fume has good performance and a wider range of applications. It is a by-product of ferrosilicon alloy plants and metal silica plants. In addition, there are natural mineral powder quartz, SiO2 powder milled by a grinder, and white carbon black powder. Electronic industry by-products, active SiO2 powder on the surface treated by silane coupling. Fused silica powder. When using zircon to produce desiliconized zirconium dioxide, the collected by-product-silica powder, and the silica powder collected in the production of metal silica.

Aluminum Silicon Carbide Castables
Aluminum Silicon Carbide Castables

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What is the role of silica powder in refractory castables?

Silica powder is added to the refractory castable to supplement the tiny pores. Through the precise particle gradation of ultra-fine powder, the strong performance of the castable is improved.

The strength of refractory castable comes from high alumina cement, and the CaO in high alumina cement reaches 5% to 8%. It will reduce the medium temperature strength of refractory castables. If the amount of low melting material is large at high temperature, it will also reduce the high-temperature performance of refractory castable. The CaO in high-alumina cement will produce hydration, and the amount of water used will increase after hydration. If the amount of water is large, the castable structure will become loose. If the superfine powder is added, the cement content in the castable can be reduced to 6%. Reduce the CaO and water consumption in the high alumina cement, thereby increasing the strength of the castable. This is the importance of silica powder in refractory castables.

High alumina refractory cement
High Alumina Refractory Cement

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Silica powder is an essential raw material in refractory castables. Adding silica powder to the castable will increase the flow value of the castable. The silica powder has a small particle size and is a spherical particle, which is extremely easy to enter the tiny voids of the castable. Therefore, adding silica powder has good water reducing effect. It can also increase the density of refractory castables and reduce porosity. So that the strength of the refractory castable is better.

The compressive strength of the refractory castable after adding silica micro powder will also change significantly at different temperatures. The initial strength is 110°C, and the medium temperature strength is 1100°C. Due to the fineness activity of SiO2 powder and the fluxing effect of CaO and other impurities in the refractory castable, a strong ceramic bond will be produced. When the high-temperature strength is 1450℃, the silica powder and the alumina powder will form mullite at high temperatures. The porosity of the refractory castable is reduced and the high-temperature strength is better.

α-Al2O3 Powder

The α-Al2O3 micro powder is made after calcining industrial alumina. Its characteristics are good dispersibility, small particles, easy sintering at high temperature, and small volume effect. Adding a certain amount of α-AL2O3 micro powder in refractory castables has a significant impact on its construction performance. Adding an appropriate amount of α-AL2O3 micro powder to the castable can improve the refractoriness of the refractory castable, and cause caramelization and multimerization reactions at high temperatures. On the other hand, it plays the role of filling micro powder and reduces the porosity of the castable. This reduces structural defects in the castable, improves its strength and resistance to slag erosion, and improves the overall performance of refractory materials.

Corundum Castable
Corundum Castable
Corundum Mullite Refractory Castable for Sale
Corundum Mullite Refractory Castable for Sale
Corundum Silicon Carbide Wear Resistant Refractory Plastic
Corundum Silicon Carbide Wear Resistant Refractory Plastic

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Rongsheng Refractory Castable Manufacturer

As a manufacturer of refractory castables, Rongsheng’s unshaped refractory workshop is equipped with advanced, fully automatic production lines. The annual output of 80,000 tons. According to different kiln types and operating conditions, we configure exclusive monolithic refractory formulations for customers. The types of products we have sold include wear-resistant refractory plastics, corundum castables, corundum mullite castables, refractory mortar, refractory ramming materials, etc. Want to know more about Rongsheng refractory manufacturers, or you need to buy monolithic refractory products. Please contact us, we will provide you with services according to your specific needs.

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Application of Zirconia Unshaped Refractories in Glass Furnace

With the continuous improvement and development of the glass furnace structure, the variety and demand of zirconia ramming materials are increasing. Domestic manufacturers of zirconia ramming materials have swarmed, forming a wave of production of zirconia unshaped refractories.

Zirconia Unshaped Refractories

Zirconia unshaped refractories can be divided into two categories: zirconia slurry and zirconia ramming material. Zirconia ramming materials are divided into two types: zirconite and zirconia alumina. The former is to add a certain proportion of crushed sintered zircon brick pieces to the zirconia mortar powder to form granular aggregates. The latter is added with granular aggregate after the fused corundum brick is broken. When using the above two ramming materials, add an appropriate amount of industrial phosphoric acid (H3PO4) with a concentration of 85%. After mixing, make the ramming materials wet and loose, and then ramming. After high-temperature sintering, it becomes a solid whole.

Rongsheng Zirconia Refractory Ramming Mass for Sale
Rongsheng Zirconia Refractory Ramming Mass for Sale

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Application of Zirconia Ramming Material in Glass Kiln

Among different zirconia ramming materials,

  • Some are zirconia ramming materials with aggregates. It is mainly used for the bottom ramming layer in the kiln for melting borosilicate glass.
  • Some are zirconia -alumina ramming materials. It is mainly used to melt the bottom ramming layer of soda-lime-silica glass, electric vacuum glass, and other alkaline glass furnaces.
  • Some belong to zirconia mortar. It is mainly used for mortar joints of zircon bricks or transition layers.
  • Some are intermediate repair materials. It is mainly used for repairing any refractory material that is not in contact with the molten glass in the flame space after corrosion.
  • There is also a mixture of ramming materials and intermediate repair materials.

Although the above-mentioned zirconia refractories have different uses, different chemical compositions, and various specifications, they are all called ramming mass refractory materials. Therefore, it often creates illusions for users. The manufacturer of Rongsheng refractory castables materials manufacturer reminds all customers that in the construction process, the wrong type should be avoided and the wrong place of the zirconia refractory ramming material should be avoided. So as not to cause the “ramming material” to peel off or be mixed in the glass liquid, causing stones and bubbles in the product. In severe cases, the glass furnace is damaged prematurely.

Zirconia Refractory Mortar
Zirconia Refractory Mortar

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The Curing Mechanism of Zirconia Unshaped Refractories

Both zirconia ramming material and zirconia refractory mortar use phosphoric acid as a binding curing agent. Both types of powders contain AL2O3. When phosphoric acid (H3PO4) is added, H3PO4 reacts with AL2O3 to form AL(H2PO4)3 at 150°C. ALPO4 is formed at 236℃ and then combined with ZrO2 in zircon sand to generate Zr(H2PO4)4, Zr(HPO4)2, and Zr3(PO4)4. At 300℃~340℃, compounds such as ZrP2O7 are formed to cause bonding and solidify. When the temperature continues to rise to 1520~1550°C, decomposition occurs again to produce (ZrO) 2P2O7+P2O5. Among them, the phosphoric acid is completely volatilized at this temperature, so that the zirconia amorphous refractory material becomes a solid and integral hard block. Therefore, it is necessary to empty the furnace and heat the kiln to make the furnace bottom temperature exceed 1550°C.

Rongsheng Refractory Materials Manufacturer

Rongsheng is an experienced refractory manufacturer. Rongsheng’s refractory materials have been recognized by customers in more than 60 countries around the world. For example, Thailand, UAE, Turkey, Kuwait, South Africa, Malaysia, Vietnam, Netherlands, Philippines, Singapore, Egypt, Russia, etc. Rongsheng’s refractories have also served many glass furnace projects. Learn more about zirconia refractory bricks and zirconia unshaped refractory products for glass kilns. Please contact us. We will provide you with services according to your specific needs.

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