rsrefractorycastable, Author at Rongsheng Refractory Castable Cement for Sale Manufacturer and Supplier

Low Cement Castable Refractory Cement For Industrial Furnaces High Dense

March 6, 2025 by rsrefractorycastable

Low cement castables have the characteristics of high density, low porosity, high strength, low wear, thermal shock resistance and erosion resistance. Low cement castables not only have the characteristics of traditional refractory materials, but also adopt the most advanced ultrafine powder application technology to improve the medium temperature strength and high temperature volume stability of the castables. The organizational structure of the product forms a firm anchor-shaped multi-directional crystal structure at high temperature. The overall structural connection stability of the lining is ensured, and the service life is increased by 3 times compared with traditional castables.

Low Cement Castable Directly from Factory

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Application of Different Types of Low-Cement Castables

Low-cement and ultra-low-cement refractory castables have been widely used in industrial kilns in the fields of metallurgical industry, petrochemical equipment, machinery equipment manufacturing and decorative building materials at this stage, and have shown good use effects and economic benefits. Different types of low-cement castables play specific roles in various application fields as follows:

Clay and high-alumina low-cement castables can be used as lining materials for various heat treatment furnaces such as hot blast furnaces, heating furnaces, soaking furnaces, and rotary kilns.
Mullite low-cement castables are used for various high-temperature burner linings, x water-cooling pipe cladding and other applications.
Corundum and chromium-containing corundum low-cement castables are suitable for the refining equipment parts outside the molten steel furnace, the lining of the power frequency induction furnace, the high-temperature wear-resistant lining of the petrochemical catalytic cracking reactor, and other occasions.
Al2O3-SiC-C Low cement castables can be used for the lining of blast furnace tapping troughs, cupola tapping troughs, integral powder spraying guns for molten iron normalization treatment and other parts.
Low cement castables of refractory and Cr-containing refractory can be used as linings of the triangular area of the top of the iron-making electric arc furnace and the linings of the components of the external refining equipment of the molten steel furnace. For example, the overall spray gun lining for the spouting metallurgical industry, the RH and DH vacuum pump degassing device and the prepreg tube lining, the DC induction furnace lining, and the high temperature wear-resistant lining of the catalytic cracking tubular reactor of the petrochemical equipment.
Low cement castables of MgO-Al2O3 or Al2O3-MgO-Al2O3 are used as lining materials for equipment such as ladles and tapping troughs.

In summary, different types of low cement castables play an important role in various industries and have been widely used and promoted.

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Advantages and Characteristics of Rongsheng High-Strength Low-Cement Castables

Rongsheng Refractory Castables Manufacturer has rich experience in the production and sales of refractory materials. Rongsheng’s environmentally friendly fully automatic amorphous refractory production line provides a reliable guarantee for the timely delivery of Rongsheng’s high-quality refractory castable products. After years of practical experience, Rongsheng has discovered the application advantages and characteristics of high-strength low-cement castables, which can effectively extend the service life of high-temperature industrial furnace linings. If you need to buy high-strength low-cement refractory castables, please contact Rongsheng for free samples and quotes. Happy to share and make progress together. Next is the advantages and characteristics of Rongsheng’s high-strength low-cement castables.

Improve the refractoriness and high temperature strength of the refractory lining.

Due to the low CaO content in low cement castables, the formation of low eutectic phases in the material can be reduced. Thereby improving the refractoriness, high temperature strength and resistance to slag erosion, especially the cement-free castable has better performance.

The refractory lining has low porosity and high bulk density.

The amount of mixing water used in the construction of low cement castables is only 1/2 to 1/3 (about 4% to 6%) of ordinary low cement castables. Therefore, the porosity is low and the bulk density is high.

After the construction of the refractory lining is completed, less cement hydrate is generated.

After the low cement castable is formed and cured, less cement hydrate is generated, and even during heating and baking, there is no phenomenon of a large number of hydration bonds being destroyed and the medium temperature strength being reduced. The low cement castable will gradually sinter as the heat treatment temperature increases, and the strength will gradually increase.

It can improve the structural stability of the refractory lining.

Low cement castable combines the characteristics of traditional refractory materials, adopts ultrafine powder application technology, and significantly improves the medium-temperature strength and high-temperature volume stability of the castable, so that the product’s organizational structure forms a firm anchor-shaped multi-directional crystal structure at high temperatures. It ensures the overall structural connection stability of the lining, and its service life can be increased by 3 times compared to traditional castables.

Why doesn’t the Ladle Containing Molten Steel Melt?

March 3, 2025February 20, 2025 by rsrefractorycastable

In steelmaking, the container for molten steel is generally called a ladle, which is mainly used to store and transport molten steel. When tapping steel, 1650℃ molten steel is directly poured into the ladle. At this time, the steel is melted, so why is the container for molten steel (ladle) safe and sound?

First, we need to understand the main components of the ladle. From the outside to the inside, the ladle is composed of a metal shell, an insulation layer, a permanent layer, and a working layer.

The insulation layer is close to the steel plate of the ladle shell. Its function is to keep warm, prevent the ladle shell from deforming, and reduce the heat conduction of the ladle wall lining.

The function of the permanent layer is to prevent the molten steel from burning through the metal shell when the refractory material of the working layer in the innermost part of the ladle, which is in direct contact with the molten steel, is partially eroded or thinned.

The working layer is in direct contact with the high-temperature molten steel, and at the same time it is subjected to the mechanical scouring of the molten steel and slag, so the refractory material of the working layer is the most important thing in the ladle lining. The height of a ladle also depends on the selection of working layer materials and masonry technology.

After the temperature of the molten steel passes through the above layers, the temperature that is finally transmitted to the ladle shell wall is only about 300℃. The temperature of the working layer is 1600℃, the temperature of the permanent layer is 800℃, and the temperature of the insulation layer is 500℃. This is why the ladle shell will not be melted.

Simply put, the container (ladle) that holds molten steel will not melt, all thanks to the refractory lining inside. Therefore, the selection of durable, high temperature and wear-resistant refractory materials is the key factor to ensure the service life of the ladle. The refractory materials of the ladle lining working layer are generally magnesia-alumina-carbon bricks and carbon composite refractory materials. The thickness of magnesia-alumina-carbon bricks is about 110~120mm. It needs to withstand high temperature, molten steel and mechanical scouring.

The Use Temperature and Requirements of the Castables for the Ladles of Foundry

The selection of castables for the ladle of the foundry is crucial. It not only affects the service life of the ladle, but also affects the efficiency and safety of production. The selection of suitable castables needs to be determined according to the specific working conditions to ensure its refractory performance and construction convenience.

Rongsheng Steel Ladle Refractory Castable

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Refractoriness of castables for ladle. The refractoriness of the AI2O3-SiC series of materials is between 1580-1770℃, which ensures the stability of the ladle in a high temperature environment.
Compressive strength. The compressive strength of the castable reaches 80MPA, which means that it can withstand the erosion of molten iron and extend its service life.
Use temperature. The use temperature of the castable for the ladle is generally not less than 1650℃ to meet the needs of high temperature operations.
Construction and maintenance. The construction of the castable should be convenient and easy to maintain to adapt to the daily maintenance work of small and medium-sized foundries.
Thermal shock stability. The castable needs to have good thermal shock resistance to cope with the thermal stress caused by temperature changes.
Performance requirements. The amount of water added to the castable should not exceed 7.3%, the number of thermal shocks should reach more than 35 times, the line change after firing should be between 0.3% and 0.8%, and the line change after re-firing should be between 0 and 0.2%.

Through these requirements, we can select the castable suitable for the foundry ladle to ensure that it is safe and efficient during use.

Steel Ladle Castables Rongsheng Manufacturer

Ladle castables are a special material used in the ladle, which can withstand high temperature and high pressure, and needs to have good fire resistance and chemical stability.

Performance Characteristics of Rongsheng Steel Ladle Castables

Good fire resistance. Ladle castables need to withstand high temperature and high pressure, so they need to have good fire resistance. Its refractoriness can reach above 1650℃, and it can work stably at high temperature.
Good chemical stability. Ladle castables need to resist various chemicals in molten steel, so they need to have good chemical stability. It can work stably in molten steel and will not react with substances in molten steel.
Good thermal insulation. Ladle castables need to keep the temperature of molten steel stable, so they need to have good thermal insulation. It can transfer heat in molten steel and keep the temperature of molten steel stable.
Good compactness. Ladle castables need to fill the internal space of the ladle, so they need to have good compactness. It needs to fill the inner space of the ladle tightly to achieve the best insulation effect.
Good unloading. Ladle castables need to be easily unloaded, so they need to have good unloading properties. It needs to be easily washed and peeled off by molten steel to facilitate the discharge of molten steel.

Rongsheng Refractory Castables Factory‘s ladle castables have good fire resistance, good chemical stability, good thermal insulation, good compactness and good unloading properties. These properties can make the ladle castable work stably in the ladle and provide guarantee for the efficient smelting of molten steel. To purchase ladle and iron ladle castables, please contact Rongsheng for free samples and quotations.

What is the Suitable Thickness of Refractory Castables Linings?

January 19, 2025 by rsrefractorycastable

Rongsheng Refractory Castables is a refractory material manufacturer with rich production and sales experience. Rongsheng, based on years of production and sales experience, can customize refractory lining solutions for high-temperature industrial furnace linings. The determination of the thickness of high-temperature refractory castables mainly depends on the working environment temperature, material properties and usage requirements. Contact Rongsheng for detailed information. ‌

‌Working environment temperature‌: The working environment temperature is the most important factor in determining the thickness of refractory castables. The higher the temperature, the greater the castable thickness required to withstand the thermal stress at high temperatures.

Monolithic Refractory Castables for CFB Boilers Refractory Linings — Monolithic Refractory Castables for Refractory Linings

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‌Material properties‌: Refractory castables of different materials have different refractory properties and thermal expansion coefficients, and the differences in these properties will directly affect the choice of thickness. For example, the thickness design ranges of light and heavy materials are 10-200mm and 200-300mm respectively.

‌Usage requirements‌: Usage requirements are also an important factor in determining thickness. Some projects may require that the castables not only withstand high temperatures but also have corrosion resistance, which requires a more sophisticated design.

Recommendations on the thickness of refractory castables in different application scenarios

‌Ladle‌: The thickness of the working lining is usually 100-150mm, and the thickness of the coating layer is 10-15mm.

‌General furnace type‌: The thickness is generally 200-230mm, and there are also designs of 150-200mm thick according to the location conditions.

‌Special requirements‌: If the furnace weight needs to be reduced, it can be designed to be 80-100mm thick, but the service life will be shortened accordingly.

As the amount of refractory castables continues to increase, the scope of use is also getting larger and larger. However, the thickness of different refractory castables and the thickness of spray coatings and coatings are different.

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The thickness of heavy refractory castables or refractory concrete cannot be less than 100mm. If it is less than 100mm, the service life of heavy castables will be affected. The most suitable thickness is 200mm. When there are certain restrictions on the use of some parts, it is also possible to pour at a thickness of not less than 100mm, and of course 150mm is also possible. If conditions permit, it is best to pour 200mm.

Of course, some user manufacturers require that refractory castables be poured at 220mm? Of course. Generally, 200mm is suitable. If 220-250mm is OK, the service life will be longer. If the user requires the refractory castable to be poured at a thickness of 50mm, be sure to tell the user that 50mm castables are not possible. Not only does it affect the service life, but also because the particles of the refractory castables are large and the thickness is too thin, it will not work at all.

The pouring thickness of lightweight refractory castables cannot be less than 80mm. If there is no specific restriction on the location of use, pouring 100-150mm is most appropriate.

There are also some user manufacturers who cannot distinguish whether to use refractory castables for pouring, coating or spraying. They should first ask the required thickness of pouring or spraying, and give users suggestions on using castables or spray coatings and coatings. The thickness of spray coatings and coatings is 30-50mm, usually 50mm is the most suitable. Too thick spray coatings or coatings will cause delamination, and too thin will affect the service life.

Therefore, as long as the user requires 30-50mm thickness, spray coatings or coatings must be used.

There are also refractory plastics, and the thickness is the same as spray coatings and coatings, 50mm is the most suitable. If 80mm is used for a specific temperature and environment, it can also be used, but the thickness cannot exceed 80mm. Too thick will also cause delamination and affect the service life.

Suggestions for the construction and maintenance of refractory castables

‌ During construction, adjustments need to be made according to the specific parts and conditions to ensure the versatility of the construction parts.
‌ In actual construction, the thickness selection needs to be adjusted and optimized according to the specific situation to ensure the quality and safety of the project. ‌

Castable Refractory Material for Heating Mantle Lining of Annealing Furnace

March 3, 2025December 21, 2024 by rsrefractorycastable

The heating hood of the bell-type annealing furnace is in a long-term working environment of alternating high and low temperatures, and is in a rising or falling working state, with poor working conditions. This causes cracks and falling off of the original furnace lining castable, resulting in large heat dissipation losses of the heating hood, serious energy consumption, and excessively high temperatures of the outer wall and burner area. Rongsheng refractory castable manufacturer can provide high-quality heating hood lining castables for annealing furnaces. Contact Rongsheng for free samples and quotes.

Refractory Materials for Heating Hood Lining

The working temperature of the heating hood used for annealing heating is about 850 ℃, and the requirements for the refractory materials of the furnace lining are relatively high. The furnace lining must have good refractory and heat insulation effects. Even if the temperature of the hot surface of the furnace lining reaches 850℃～900℃, the average temperature of the outer wall of the heating hood remains ≤ room temperature + 45℃, and the average temperature of the shell of the burner area remains ≤ room temperature + 55℃. However, due to the cracks and cracking and shedding of the original lining castable of the heating hood, the average temperature of the outer wall and the shell of the burner area is statistically: the outer wall> 75℃ (room temperature 20℃), the shell of the burner area> 85℃ (room temperature 20℃), which has exceeded the design temperature index. Therefore, the refractory materials of the heating hood lining of the annealing furnace are modified to effectively reduce heat loss, reduce the temperature of the outer wall of the furnace and the shell of the burner area, and reduce energy waste.

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Problems with Refractory Materials for Heating Hood Lining

The heating hood is welded from large structural steel and a solid electroplated cylinder. The refractory materials for heating hood lining are currently mainly castable structures, which have the following disadvantages:

(1) The lining is a castable structure, the temperature of the outer wall of the furnace top is too high, the heat dissipation loss is large, the energy consumption is serious, and the working environment is harsh.

(2) The lining material is a heavy and light castable structure, and the thermal shock resistance and mechanical vibration performance of the lining material are poor. Cracks are easily generated during use, resulting in serious cracking and peeling of the castable lining, shortening the service life, and making maintenance difficult and expensive.

(3) The castable structure of the lining needs to be baked before use. If the baking effect is not good, it will affect the performance of the lining.

Renovation Plan for Refractory Castable Materials of Heating Hood Lining

Choice of refractory materials At present, refractory ceramic fiber materials are widely used as refractory materials for furnace lining in domestic bell furnace applications. Refractory ceramic fiber materials are a lightweight and efficient thermal insulation material. Compared with traditional insulation materials, they have the following advantages:

(1) Low volume density: Fiber furnace lining is more than 75% lighter than lightweight insulation brick furnace lining and 90%~95% lighter than lightweight castable furnace lining.

(2) Low thermal conductivity: When the average temperature of refractory fiber furnace lining is 400℃, the thermal conductivity coefficient is <0.11 W/m·K. When the average temperature is 600℃, it is <0.16 W/m·K. When the average temperature is 1000℃, it is <0.22 W/m·K, which is about 1/8 of lightweight clay bricks and 1/10 of lightweight heat-resistant lining (castable), with significant insulation effect.

(3) High thermal sensitivity: The thermal sensitivity of refractory fiber lining is much better than that of conventional refractory lining. At present, heating furnaces are generally controlled by microcomputers. The high thermal sensitivity of fiber lining is more suitable for the automatic control of industrial kilns.

(4) No need to bake the furnace: The lining can be put into use after the construction is completed, and no baking procedure is required.

(5) Simple construction: No expansion joints are required during the construction process, and the influence of construction technical factors on the insulation effect of the lining is small.

(6) The disadvantages of refractory ceramic fiber lining are that it is not wear-resistant, has poor thermal shock stability, and is not resistant to hot air erosion. This requires special attention. After long-term use, it will be found that ceramic fiber cotton will produce slag and agglomeration. Sometimes, improper operation will cause pieces to fall off with a slight collision. This may also be due to the fact that the material itself is an insulation product.

Refractory fiber lining has become a trend in the development of furnace linings, representing the level of modernization of industrial furnaces. Whether refractory fiber lining is adopted or not directly determines the use effect, product quality and output of the furnace. Therefore, the selection of refractory ceramic fiber materials to replace the original furnace lining materials must meet the use requirements of the heating hood of the full hydrogen hood annealing furnace in the cold rolling mill.

Use of Amorphous Refractory Materials in Blast Furnaces — Castable Refractory Lining for Furnaces

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How High a Temperature Can a Refractory Castable Withstand?

The temperature resistance of a refractory castable depends on the material composition and preparation process. Generally, it can withstand high temperatures, and different types and formulations of refractory castables have different temperature resistance ranges. Special refractory castables can withstand temperatures up to 2000°C, and attention should be paid to the temperature change rate and temperature gradient when using them. The temperature resistance of a refractory castable depends on its material composition and preparation process. Generally speaking, refractory castables can withstand high temperatures, but the specific temperature resistance range varies depending on the type and formulation of refractory castables.

Some common refractory castables, such as high-alumina refractory castables, corundum refractory castables, and low-cement refractory castables, have higher temperature resistance. These materials can generally withstand high-temperature environments of 1500°C to 1800°C.

However, for higher temperature applications, such as in steelmaking, glassmaking, or other high-temperature processes, refractory castables with special formulations and preparation processes may be required. These special refractory castables can withstand higher temperatures, reaching or even exceeding 2000°C.

It should be noted that even if the refractory castable can withstand high temperatures, it is also necessary to pay attention to the rate of temperature change and the temperature gradient to avoid cracking or thermal shock of the refractory castable due to rapid changes. Therefore, in practical applications, it is necessary to select appropriate refractory castables according to specific circumstances and follow relevant instructions and operating specifications.

Moisturizing and High-Temperature Properties of Refractory Plastics

January 18, 2025November 19, 2024 by rsrefractorycastable

Plastic is a refractory material that was developed and applied earlier and is mainly used in heating furnaces, electric furnace tops, and other parts. Due to its shortcomings such as short storage time and poor fire resistance, its application range is limited. However, this refractory material has some irreplaceable advantages, such as the high-temperature strength of the furnace body constructed with plastic, excellent thermal shock resistance, low thermal conductivity, and flexible construction methods.

Selection of Refractory Plastic Aggregates

Refractory plastics should have excellent plasticity, moisture retention, and high-temperature performance. To meet these conditions, it is very important to select suitable raw materials. The raw materials should have good volume stability. During the heating process, they can be well-sintered and reacted with binders such as clay. Aggregates should have appropriate particle size and grading. Generally, the critical particle size of refractory plastic aggregates is less than 10 mm, the aggregate content is 55% to 65%, and the powder content is 35% to 45%. Through strength tests and moisture retention tests, it was found that although the plastic produced with grade 3 high aluminum and grade 2 high aluminum as the main raw materials has a higher strength after burning, the moisture retention of the material is poor. Therefore, it is determined to use special grade high aluminum alumina as the main raw material, and it is required to be sintered densely and have a low impurity content. In order to improve the moisture retention performance, the iron oxide content in the material should be strictly controlled.

Phosphate Bonded High Alumina Refractory Plastics — High Alumina Refractory Plastics

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Effect of Clay and Powder Addition on the Performance of Refractory Plastic

Binding clay is added to plastic, which mainly plays a bonding role and improves its plasticity and sintering performance. The particle size of clay should generally be less than 200 mesh. Its dosage should be minimized while ensuring the plasticity and bonding ability of plastic. If too much is added, the linear shrinkage of plastic will increase after high-temperature firing, the load softening temperature will decrease, and the high-temperature creep will increase. If the amount added is too little, the plasticity of the material cannot be guaranteed. Through experiments, it is determined that the amount of clay added is 5% to 15%. In order to reduce the linear change of plastic after firing, an appropriate amount of kyanite is added. Since kyanite produces volume expansion at high temperatures, it can offset part of the shrinkage of plastic. Its fineness is 150 mesh, and the amount added is controlled at about 5%. In order to improve the plasticity and thermal shock resistance of plastic and further reduce the impurity content in the raw materials, alumina powder, and silicon powder are added. This can not only improve the construction performance of the material but also increase the medium and high-temperature strength of the product. The total amount of the two is generally controlled at 6% to 12%, which is more reasonable.

Through experiments, it is found that when the plastic index is around 14%, the plastic is relatively hard and the construction performance is poor. When the plastic index is around 26%, the plastic feels softer and the construction is easier. In order to facilitate construction and meet the requirements of other performance indicators. Through repeated experiments, it is confirmed that the plastic index of the plastic is about 28%.

Selection of Fire-Resistant Plastic Binder

In order to make plastic have higher strength and excellent moisture retention performance, various binders were tested, such as phosphoric acid, water glass and aluminum sulfate. Through experiments, it can be proved that plastic with phosphoric acid as binder has higher strength index. However, due to the strong acidity of phosphoric acid and the high iron oxide content in the raw material, phosphoric acid can easily react chemically with iron oxide, which makes the moisture retention performance of plastic worse. Using aluminum sulfate as a binder, plastic has a longer moisture retention performance, but the strength index of plastic cannot meet the use requirements. Using water glass as a binder, the moisture retention performance of the material is better in the short term, but after a long storage time, the construction performance of plastic deteriorates. In addition, when the plastic combined with water glass is baked, the hard shell produced on the surface will have an adverse effect on the strength of the plastic construction body. Through repeated experiments, it was determined that the two binders of phosphoric acid and aluminum sulfate were used in combination, so that the moisture retention performance and strength index of the plastic can meet the use requirements.

High-Strength Aluminum Phosphate Bonded Refractory Plastics

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Factors Affecting Moisture Retention Performance

Influence of aggregate types

Through continuous moisture retention experiments, it was found that the moisture retention performance of plastics with high-aluminum from special downdraft kilns as aggregates is significantly better than that of plastics with other low-grade aggregates. This is due to the dense sintering of special-grade aggregates and the low water absorption rate of particles.

Influence of binder types

Binders have the greatest impact on the moisture retention performance of plastics and also play a key role in other properties. If improperly selected, plastics will not meet the requirements of use.

Through experimental research on the moisture retention performance and compressive strength performance of the test blocks, as well as comprehensive considerations such as raw material costs, phosphoric acid, and aluminum sulfate were finally selected as composite binders. This can not only meet the moisture retention performance requirements of plastics but also meet the requirements of medium and high-temperature strength.

Effect of admixture types

Experiments show that adding organic acids (such as oxalic acid) and dextrin and other admixtures can prevent or delay the reaction between the binder and the refractory material, and play a role in extending the moisture retention of plastic. Some admixtures are oily and can effectively reduce the agglomeration of plastic, which mainly extends the moisture retention of the material from a physical aspect. Oily moisturizers and main binders such as phosphoric acid are not miscible but can reduce the chance of chemical reactions between phosphoric acid and raw materials, making the moisturizing effect better.

When used in furnaces such as heating furnaces and annealing furnaces, plastic has certain advantages over castables. It does not require on-site mixing equipment and can be directly constructed. It has a large viscosity and does not flow. It is easier to combine with the old lining during repair, and local repairs can be performed without templates. Because it has a low water content, the requirements for baking conditions are not very strict.

Conclusion

(1) Using high-grade downdraft kiln high-alumina bauxite as the main raw material can significantly improve the moisture retention performance of plastics.
(2) Using phosphoric acid and sulfuric acid in a composite form, and adding an appropriate amount of additives, plastics with relatively good moisture retention and strength indicators can be produced. The effect of using a single combination is not ideal.
(3) Select high-grade high-alumina bauxite with dense sintering and low impurity content to minimize the iron oxide content in the material. In addition, adding an appropriate amount of moisturizing agent can significantly extend the moisture retention period of plastics.

Rongsheng amorphous refractory castable manufacturer can provide high-quality amorphous refractory lining materials for high-temperature industrial furnaces. If you need to purchase refractory plastics to extend the service life of refractory furnace lining materials. Please contact Rongsheng for free solutions for high-temperature industrial furnace linings.

Refractory Castable Materials for Boiler Furnaces

December 16, 2024October 29, 2024 by rsrefractorycastable

The boiler furnace is a three-dimensional space surrounded by furnace walls for fuel combustion. Its function is to ensure that the fuel is burned as much as possible and to cool the flue gas temperature at the furnace outlet to a temperature that allows the convection heating surface to work safely. Rongsheng Refractory Material Manufacturer can provide high-quality boiler furnace refractory materials – refractory lining maintenance services for high-temperature industrial furnaces. Contact Rongsheng for detailed information.

High-Alumina Refractory Castables Manufacturer

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Refractory Castables for Furnace Lining

Common refractory castables for furnace lining include steel fiber, special high aluminum, brown corundum, silicon carbide, mullite, etc. Aggregates and powders made of high-temperature resistant or high-temperature wear-resistant products, with binders, ultrafine powders, and other products added, are mixed and made. They can be cast or made into high-temperature-resistant prefabricated parts and hoisted for construction.

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High-Temperature Resistant Plastic Refractory for Furnace Lining

High temperature resistant plastic for furnace High temperature resistant plastic for furnace is basically the same as castable material, but the combination and construction methods are different. It is composed of 80% to 85% high-strength aggregate and fine powder. After adding binder and plasticizer, a small amount of blending agent is added. After sufficient mixing, it is a kind of hard mud paste, which can be made of various high temperature resistant raw materials. It belongs to a more plastic and shape-changing refractory material.

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Ramming Material Refractory for Furnace Lining

Compared with other amorphous refractory materials of the same material, ramming material for furnaces is dry or semi-dry and loose. The dense structure is obtained by strong ramming, and the combination will have density only when it is heated to the sintering temperature. Compared with castables and plastics, it has more reliability and corrosion resistance at high temperatures. However, its service life depends to a large extent on the pre-burning before selection or the sintering amount during the first use. If the heating surface is sintered as a whole without cracks and does not separate from the bottom layer, the service life can be improved.

The refractory materials for furnaces should not only look at the product quality, but also the furnace drying is an important link. The furnace should not only be baked, but also the necessary furnace boiling should be implemented. The heating boiler in winter should also be baked before it is put into operation to drive away the moisture in the furnace body and chimney flue. Boil the furnace means to put scientifically proportioned chemicals into the furnace to dissolve and remove the oil, dirt, rust, etc. attached to the inner wall of the heating surface during the manufacturing or transportation of the boiler, so as to ensure the safe operation of the boiler and the quality of steam and hot water.

Causes of Damage to Refractory Castables for Furnaces and Methods of Repairing Castables

Speaking of the current structure of boilers, it is estimated that a large part of the structure is selected refractory castables. Refractory castables not only have high performance and good performance. In many cases, refractory castables can be modified to produce different properties of refractory materials, which is one of the reasons why refractory castables are very popular now.

However, one of the puzzling problems is that refractory castables are used for a long time, or a considerable part of the products are extremely vulnerable to damage during the curing process. When building boilers, the use of aluminate cement refractory castables is mainly caused by the combination of aluminate cement and castables.

Surface crushing caused by alkaline impurities

In the material, the presence of soluble alkali increases solubility and accelerates the reaction as an important prerequisite. In cement castables, the increase in cement content and the increase in system alkalinity will lead to larger hydrated minerals, which is conducive to the reaction. Curing environment temperature and humidity are important factors for damage. Generally, the greater the humidity, the easier it is to wet the pores in the casting body. Under humid conditions, dissociation is easier and the reaction is smoother. The density of the green body is also an important factor. When the porosity of the green body is high, water in the air is more likely to diffuse into the green body, so that the damage reaction continuously enters the depth of the green body, resulting in casting. The crushing of the table and the inside will damage the material. In addition, the shape and thickness of the blank also affect the progress of the reaction. In addition, the quantity and quality of construction water will also affect the damage.

Surface pulverization caused by carbonation reaction

Surface pulverization caused by carbonation reaction can be divided into two types. One is direct carbonation, where carbon dioxide directly reacts with the hydration products of cement to form a calcium carbonate-calcium aluminate complex. It closes the surface pores and causes surface hardening, thereby inhibiting pulverization. The other is carried out by the catalysis of sodium ions in the presence of soluble alkali metal oxides. This is similar to the mechanism of sodium ion damage, which may lead to the destruction of the castable lining.

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Repair of Furnace Lining Refractory Castables

The damage and repair methods of furnace lining refractory castables are mainly used to solve surface damage.

Wash high-purity raw materials to reduce the content of soluble alkali metals. When preparing refractory castables, choose high-quality refractory aggregates as much as possible, and choose washed and baked raw materials with low alkali content (such as bauxite and corundum). If the raw materials are not calcined (such as andalusite), choose more cautiously and try to use composite sodium and low concentration mixtures. The dispersion effect and filling effect of micropowder are conducive to improving the density of castables. However, when selecting micropowder, the impurity content of micropowder should be properly controlled to minimize the amount of cement containing high alkali metal impurities.
Strengthen the control of construction water quality.
Reduce the contact between the surface of the castable and the air. Surface coatings, coverings, etc. can be used to close the surface pores and minimize the diffusion of CO2 and water vapor into the castable to prevent damage reactions.
Accelerate hardening, dry the green body as soon as possible, promote the development of green strength, and make the damage reaction lose conditions.

After a period of operation, the damage to the original furnace lining has been restored, and the damage to the furnace lining material has not been aggravated. Therefore, when using castables, we should take correct measures in time to make good transformation of the boiler. Rongsheng amorphous refractory castable manufacturer is a powerful manufacturer and seller of refractory materials. To purchase refractory castable products for furnace lining, please contact Rongsheng for free samples and quotations.

Long-Life Thermal Insulation Refractory Castable for Ladle Furnace Lining

November 11, 2024October 15, 2024 by rsrefractorycastable

Ladle is an essential container in the steelmaking process. With the continuous development of smelting technology, especially the processing of out-of-furnace refining LF and RH, its role has evolved from the simplest receiving molten steel to a furnace that undertakes certain smelting functions. If the molten steel stays in the ladle for a long time, it will inevitably cause the temperature of the molten steel to dissipate, and the ladle lining with high thermal conductivity will cause the heat dissipation loss of the molten steel to increase. The deformation of the ladle shell becomes more serious, and the temperature drop rate of the molten steel increases, causing serious slag hanging nodulation, and cold steel on the ladle wall. Excessive low temperatures may even force the middle package to cut off the flow and final pouring. It not only affects the quality of the cast slab but also reduces the yield of molten steel and increases the production cost. Therefore, thermal insulation ladles are increasingly becoming a need for steel mills. The structural model of thermal insulation ladle refractory materials is usually lightweight insulation panels or nano panels + permanent layer castables + working layer refractory materials. Rongsheng’s long-life thermal insulation refractory castable for ladle furnace lining. Contact Rongsheng to get a free quote.

Lightweight High-Strength Castable for Steel Ladle

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Insulating Refractory Castables for Ladles

The insulation board itself, which plays the most important role in thermal insulation, needs a layer of refractory material to protect it. The material must first protect the insulation material from too much pressure, and secondly, protect the insulation material from exceeding the operating temperature (if it must be below 1000°C), then the ladle Permanent layer castables are such important materials. The ideal permanent layer refractory material for thermal insulation ladles should have good thermal stability, thermal insulation, corrosion resistance, safe and reliable application, complete structure, and long service life. In order to maintain the good thermal insulation performance of the ladle and reduce the temperature drop of the molten steel, the performance evaluation of the new CA6 castable and the lightweight mullite castable was conducted in this work and applied to the ladle, achieving a relatively good comprehensive thermal insulation effect.

Performance comparison of thermal insulation refractory castables for ladles

At present, the permanent layer materials of ladles are mostly ordinary high-aluminum castables, and the main raw material is bauxite. There are the following shortcomings in the use of this refractory castable. First, the thermal conductivity is high, which causes energy loss during use. Second, the refractoriness is low. If the working layer is used abnormally and the molten steel directly contacts the permanent layer, the probability of steel leakage will be greater and the safety factor is low. Third, the volume density is larger and the empty ladle weighs more. Therefore, the special requirements for ladle insulation are not met, and it is necessary to develop new permanent layer castables with excellent comprehensive properties. Performance comparison of new CA6 castable and lightweight mullite castable.

Among them, the CA6 raw material (CaAl12O19, abbreviated as CA6) is the calcium aluminate phase with the highest Al₂O₃ content in the CaO-Al₂O₃ system. Its melting point is 1875℃, its thermal expansion coefficient is 8.0×10-6℃⁻¹, its particle volume density is 2.70g·cm⁻³, and its apparent porosity is 26.8%. The fire resistance of this material is similar to that of plate corundum, but its thermal conductivity is only 1/3 of corundum. It is a new type of high-quality thermal insulation material that has emerged in recent years. CA6 castable is made of CA6 as aggregate, and the matrix part is made of plate-shaped corundum fine powder, alumina powder, and calcium aluminate cement as binding agents. The volume density of spherical lightweight mullite particles is 1.59g·cm⁻³, and the apparent porosity is 38.9%. The lightweight mullite castable is made of microporous M70 spherical lightweight mullite balls as aggregate, and the matrix part is made of plate-like corundum fine powder, alumina powder, and calcium aluminate cement as binding agents to ensure Better resistance to slag erosion to improve the safety of the permanent layer.

The volume density of lightweight mullite castable is 2.17g·cm ⁻³, and its unit weight is 24% lower than the currently used high-aluminum castable. At the same time, the thermal conductivity is reduced by 16%, which can achieve the purpose of lightweight and low thermal conductivity of the ladle. CA6 castable is also 5.6% lighter than ordinary high-aluminum castable, and its thermal conductivity is reduced by 26%.

Pour the original ladle permanent layer castable B, the new CA6 castable C, and the lightweight mullite castable 3# into crucibles respectively. Add the final converter slag and conduct a slag corrosion resistance test on the crucible under the condition of 1500°C for 3 hours. Observe the resistance to melting loss and penetration of different materials. After completing the test, the crucible was cut open. The erosion status is as follows:

CA6 castable has the best resistance to erosion and penetration, with a large amount of slag remaining in the crucible hole; light mullite castable has the second-best resistance to erosion and penetration. The boundary between ordinary high-aluminum permanent layer casting slag and refractory material is not clear, and the crucible refractory material and slag are melted together. The resistance to penetration is slightly better than the resistance to erosion, indicating that more liquid phases have appeared in the high-aluminum castable at 1500°C. Therefore, the material needs to be improved to improve its high-temperature resistance, which is very important for the safety of the ladle. The micropores of spherical lightweight mullite are beneficial to improve corrosion resistance and permeability, so this lightweight material can also perform better in insulation and corrosion resistance.

Application Comparison

The above three kinds of castables are used for construction and application on 300t steel ladle. The target requirement of the lightweight mullite castable and CA6 castable for the permanent layer of the thermal insulation ladle is to have both good resistance to molten steel erosion and good thermal insulation properties. At the same time, the furnace has good structural integrity and a stable thermal insulation effect during the furnace service process. After three furnace campaigns, the surface conditions of the permanent layer of the steel ladle were different, and cracks of varying degrees appeared in the permanent layer of the steel ladle in the later stages of the furnace campaign. This is related to the thermal shock resistance, strength and damage of the material during the unpacking process. The comprehensive technology of how to reduce the cracking of the permanent layer material of the thermal insulation ladle still needs further in-depth research.

Judging from the average temperatures of each slag line in each furnace, the steel shells of the uninsulated ladle slag lines are all above 320°C, while the average temperatures of the four test slag lines using insulation are below 280°C. Generally, the temperature of the slag line steel shells has dropped. 50～100℃. The temperature drop of the steel shell in the wall part is between 20 and 50°C, which varies slightly depending on the configuration of the insulation material and permanent layer material. The insulation material of the thermal insulation test package remained in good condition during the furnace service period, and the average temperatures of the slag line and wall steel shell were lower than those of ordinary steel ladles, indicating that the permanent layer played a good protective role. In order to ensure safety, the current situation of obvious cracks in the new permanent layer material after two furnace operations still needs to be optimized and improved to ensure that it can be applied to four furnace operations.

In Conclusion

Insulated ladles have become an important technical measure for steel companies to save energy, protect the environment, and improve the quality of steel products. The permanent layer materials of ladles have been given higher requirements. The physical properties such as strength and strength of the developed CA6 castable and lightweight mullite castable meet the application requirements of the permanent layer of the ladle. At the same time, they have better thermal insulation and corrosion resistance than conventional high-aluminum castables and can protect thermal insulation materials. The function ensures that the ladle maintains good heat preservation during the furnace service period. Further in-depth research is needed on the comprehensive technology to reduce the cracking of the permanent layer material of the thermal insulation ladle.

Rongsheng Refractory Castable Manufacturer

Rongsheng refractory castable manufacturer, an environmentally friendly and advanced fully automatic unshaped refractory material production line, provides a reliable guarantee for refractory castable lining materials for high-temperature industrial furnaces. Annual output is 6W tons. Rongsheng Manufacturer can provide high-quality insulation and refractory castable products for ladles, rotary kilns, and non-ferrous smelting furnaces, as well as the design and construction of insulation layer refractory lining materials. The ladle is made of long-life insulation castables and is shipped directly from the manufacturer at a low price. Contact Rongsheng for free details.

Application of Monolithic Refractory Materials in Blast Furnace

October 1, 2024 by rsrefractorycastable

The main unshaped refractory materials used in blast furnaces include refractory castables, refractory spray coatings, refractory plastics, and refractory coating materials. The use of amorphous refractory materials in high-temperature industrial furnace linings can effectively extend the service life of blast furnaces and improve the overall application efficiency of the equipment. It can also effectively reduce internal wear problems caused by increased labor intensity.

Monomorphous Refractory Materials for Blast Furnaces

How to use unshaped refractory materials in blast furnaces, and what are the characteristics and uses of unshaped refractory materials? The development and application of amorphous refractory materials can effectively improve the construction efficiency of the furnace lining, shorten the construction period, improve the integrity of the furnace lining, and enhance the overall performance of the lining body. It can effectively help enterprises reduce the number of furnace shutdowns and furnace repairs and improve economic benefits. Rongsheng Unshaped Refractory Castable Materials Manufacturer is a professional manufacturer and seller of refractory furnace lining materials. Furnace lining solutions can be customized according to the actual working conditions of the kiln. Contact us to get free samples and quotes.

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Characteristics of Unshaped Refractory Materials Commonly Used in Blast Furnaces

Compared with shaped refractory materials, the entire combustion process is canceled during the manufacturing process, which also makes the material itself amorphous. This is because the production process of amorphous refractory materials is relatively simple, and the materials are malleable. In the subsequent use process, unshaped refractory materials have the characteristics of convenient shaping. In this regard, during the casting process of the preliminary equipment, this method can be used to carry out the internal transformation of its furnace construction. This not only ensures cost reduction, but the simple manufacturing process can also increase the processing speed. It is worth noting that the service life of amorphous refractory materials is similar to that of refractory bricks, and its fire resistance and chemical stability can also reach the level of refractory bricks of the same type. Therefore, prefabrication can also be carried out before the furnace lining construction, and the unshaped refractory materials can be directly made into larger refractory precast blocks. Then, it is baked at low temperature before use, so as to ensure that it can survive long-term use inside the casting blast furnace. It can effectively extend the service life of the inner wall of the blast furnace and reduce the occurrence of internal damage caused by temperature changes.

The Use of Amorphous Refractory Materials in Blast Furnaces

(1) When manufacturing the internal structure of a blast furnace, the brick joints are the weak links of the blast furnace brick masonry. This also makes the corrosion process mainly destroy the joints during its application. In order to ensure that the overall service life of the blast furnace is extended, the damage and damage caused by furnace lining erosion can also be reduced. When filling the brick joints, it is necessary to use refractory mud to modify them, so as to ensure that the sealing degree of the furnace lining can be improved. Since refractory mud itself is an amorphous refractory material, during the preparation process, in order to ensure the overall adhesion and refractory degree, it is necessary to identify the brick joint material of the furnace lining. And the temperature of its application effect needs to be debugged, and then its gaps must be matched. This can ensure that after the filling is completed, the blast furnace lining can completely form a smooth hole. This ensures that the overall high-temperature resistance of the lining is reduced due to erosion.
(2) During the process of stacking the blast furnace lining, it is necessary to ensure that there is a cooling stave between the lining and the furnace shell. This kind of cooling stave requires the addition of filler so that the insulation or adhesive between the two layers of furnace lining can form its own protective film. And it can also bring out the application effect of internal substances. When a blast furnace is put into production for a period of time, the waist and lower part of the furnace body will be severely eroded due to the erosion of thermal energy. This also causes the composite energy to increase when it is working, causing the cooling equipment to be damaged under high temperatures and high pressure. At this time, bulges or cracks will appear on the surface of the furnace shell. In this regard, it is necessary to press the amorphous refractory material into the extended furnace body through the grouting method, so as to effectively increase the service life of the blast furnace. It can also reduce a series of safety risks caused by equipment damage.
(3) When cracks appear in the blast furnace lining, the surface can be treated by gunning the lining. Under normal circumstances, a layer of unshaped refractory material needs to be sprayed at this time to prevent fission caused by cracks. At the same time, the blast furnace itself is forged with high-quality bauxite and graphite as the main raw materials. Therefore, adding a certain amount of silicide can ensure that it becomes a hard object after high pressure and high temperature. It has the functions of high-temperature resistance and good thermal conductivity. Therefore, when used, it can also effectively improve its service life.

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Application Methods of Unshaped Refractory Materials in Blast Furnaces

New water wall technology

During the stacking process of the blast furnace, it is necessary to ensure that the internal cooling protection wall is formed by injection. The lining of this refractory material can also play the role of internal heat preservation and external heat insulation so that it can effectively reduce the loss of heat energy. Under normal circumstances, after one to two years of use, the internal cooling staves of a blast furnace will break. This also leaves exposed parts on the surface of the cooling stave, which increases heat energy consumption and also leads to safety hazards. Therefore, it can be said that if there is no refractory material, the slag will directly adhere to the cooling stave after combustion and cooling. Due to the large difference in its own expansion coefficient, the slag skin will fall off at any time. In order to effectively solve this problem, cermet lining can be used to transform it. Not only can it effectively protect its cooling stave, but its cermet lining can also be used to improve its fire resistance through the application of its own thermally conductive fibers, and ensure that its own metallic characteristics can be intact. This also makes it have the characteristics of better thermal conductivity and better plastic deformation ability. During application, the material will not become brittle even in high-temperature environments.

Furnace lining injection technology

Carbon monoxide inside the blast furnace will cause the deposition of carbon elements in the refractory material, which will in turn cause the overall structure of the material to be destroyed. The problems displayed on the furnace wall are internal fractures or a reduction in the strength of the material itself, or the material has cracked, resulting in irregular fractures at both ends of the material. Therefore, if it contains iron elements inside, it will catalyze this reaction, thereby increasing its overall collapse efficiency. Because, among all refractory materials, iron oxide must be used, which will react with carbon monoxide and form iron element. These iron elements happen to act as catalysts reflected in carbon deposition. Therefore, under the normal application of the blast furnace, this problem is unavoidable, which also causes the blast furnace to reduce its service life.

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Nano Silica Combined with Pouring Technology

After a blast furnace has been used for several years, its taphole will show varying degrees of wear and tear, and its working efficiency will be reduced. Traditionally, when repairing it, mud cannons are used to press in to achieve overall improvement. However, this will not only increase the consumption of mud cannons, but also fail to cure the problem. In this regard, it is necessary to apply some new technologies to realize the transformation of its iron mouth. At the current stage, nano-silica combined with castable casting is one of the main application methods for taphole repair. Since silicon carbide is the main raw material, silica is used as a gelling agent, which not only effectively improves its overall structural strength, but also enables rapid drying without causing explosions. At the same time, after the repair is completed, it can also achieve an effective increase in its own structural strength.

The use of amorphous refractory materials in blast furnaces can effectively increase the service life of the furnace lining and save production costs for enterprises. Rongsheng Unshaped Refractory Materials Manufacturer, an environmentally friendly and fully automatic unshaped refractory material production line, provides a reliable guarantee for the longevity of lining materials for high-temperature industrial furnaces. Moreover, our professional technical team provides customized furnace lining materials and customized furnace lining solutions. Contact us to improve the life of your furnace lining.

Unshaped Refractory Aluminum-Magnesium Spinel Castables Application and Construction

September 24, 2024 by rsrefractorycastable

Rongsheng Unshaped Refractory Materials Manufacturer is a powerful manufacturer and seller of refractory materials. Rongsheng Environmental Protection’s fully automatic unshaped refractory material production line provides a reliable guarantee for the efficient and long-life operation of high-temperature industrial furnace linings. Among them, the application of alumina-magnesium spinel castables is becoming increasingly widespread. Contact us to get free samples and quotes. This article will introduce the practical application of unshaped refractory materials, alumina-magnesium spinel castables.

Application and Construction of Aluminum Magnesium Spinel Castables

Tundish aluminum-magnesium castables and ladle aluminum-magnesium castables are both based on aluminum-magnesium spinel materials. There are also steel fiber aluminum-magnesium castables, which are the main working layer refractory castables often used in steel plants. Because they are more convenient during construction, they are welcomed by steel mills and enterprises. However, sometimes due to changes in the construction conditions of alumina-magnesia spinel castables, some problems may occur, affecting the use effect and life of the furnace lining.

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Problems and Solutions in the Construction of Aluminum-Magnesium Spinel Castables

Solidification time is an important factor affecting the construction of aluminum-magnesium castables. The ambient temperature has a great influence on the solidification time of aluminum-magnesium castables, especially in summer. When the ambient temperature exceeds 35°C, aluminum-magnesium castables tend to solidify quickly, which brings a series of problems to the casting construction:

①Increased the labor intensity of construction workers. When the ambient temperature is high and the solidification time of the castable is shortened, the rheology of the castable itself becomes worse. Especially when the castable is rapidly solidified, the castable released from the mixer has no time to enter the bag, and has solidified on the upper surface of the bag and the launder. This makes feeding castables into the wall more labor-intensive.

②Influence the service life. In hot summer, workers often add more water to increase the fluidity of castables. Due to the increase in water consumption, the porosity of the castables increases and the strength decreases after drying. In addition, when the ambient temperature exceeds 40°C, even if more water is added, the castable will still tend to set quickly, affecting the service life.

③ Difficulty in rebirth. Under normal circumstances, after the ladle is poured, it needs to be left for 24 hours before it comes out. However, in the hot summer, due to the shortened solidification time of the castable, the castable and the tire package are tightly stuck together, making it difficult to remove the tire.

Therefore, whether it is from the perspective of reducing the labor intensity of workers, or creating a good condition for pouring construction, extending the service life of castables, and reducing usage accidents. It is necessary to fundamentally adjust the solidification time of aluminum-magnesium castables to meet the on-site usage requirements. After a period of research, it was found that lignosulfonate can change the setting time of castables, so that the initial setting time of aluminum-magnesium castables can be extended to more than 30 minutes even when the ambient temperature exceeds 35°C. This completely solves the problem of short solidification time of aluminum-magnesium castables in summer. It should be noted that the solidification time of aluminum-magnesium castable is related to the amount of lignosulfonate added. On the premise of meeting construction requirements, the smaller the amount added, the better. In addition, as the seasons change, the amount added must also be adjusted accordingly. Generally, a large amount is added in summer, and less or even no amount is added in winter. If more lignosulfonate is added in winter, the final setting time of the aluminum-magnesium castable will be extended, which will cause material collapse during normal operation, which is harmful.

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Problems and Solutions when Using Aluminum-Magnesium Spinel Castables

(1) Cracks.

Aluminum-magnesium castables crack during use, reducing their service life. When the ladle was used for 5 heats, cracks began to appear on the inner wall of the ladle, covering the entire ladle wall. As the number of uses increased, the cracks became deeper and wider. When more than 20 furnaces were used, they had to be discontinued. To solve the problem of castable cracks, some methods have been tried:

① Replace the bauxite clinker calcined in the vertical kiln with bauxite calcined in the down-flame kiln. In this way, the sinterability and bulk density of alumina are increased. It was thought that the volume shrinkage caused by incomplete calcination of the alumina and re-sintering during use could be reduced, but this was not successful.

② It is believed that the cracks are related to the total amount of fine powder in the castable. Trying to reduce the fine powder in the castable to less than 30% (mass fraction), or as low as 25%, did not solve the problem.

③ Solve the cracks starting from a chemical reaction. Because Al2O3 and MgO can generate alumina-magnesia spinel under the action of high temperature, it is accompanied by large volume expansion. After a series of tests and adjusting the ratio of Al2O3/MgO, satisfactory results were not achieved. Even when the MgO content is too high, peeling occurs instead.

Finally, the following method is basically used to solve this problem:

① Increase the upper limit of aggregate particle size from the original 15mm to 25mm. Among them, the 20-25mm part accounts for 7.2% (mass fraction) of the total. This is due to the presence of oversized particles, which not only act as a skeleton but also change the direction of long cracks, helping to prevent the expansion of internal cracks.
② Add zircon powder to the matrix. This zircon powder is produced in Australia, and its ZrO2 content is about 66%. Since ZrO2 itself has a high melting point, it can absorb CaO in the slag during use, react to generate CaZrO3 with high melting point and high corrosion resistance, and seal pores and cracks. At the same time, due to the presence of zircon, micro-crack structures can also be formed in the castable to improve the high-temperature performance of the castable.
③ Reduce the dosage of activated silicon carbon powder as much as possible. Since the quality of silica fume powder is unstable and a large amount is added, a lot of impurities will be brought in, which is detrimental to use. Controlling the amount of silica fume in the castable below 1.5% (mass fraction) will achieve better results.
④When pouring, it is also critical to strictly control the amount of water added and ensure uniform vibration.

(2) Peeling

Spalling is also one of the common problems in the use of aluminum-magnesium castables. It is the result of uneven stress within the castables. If A12O3 and MgO in the matrix are affected by high-temperature molten steel during use, they will easily react to form MA spinel, accompanied by a large volume expansion. If this reaction is very intense, structural peeling will easily occur under the impact of molten steel. Therefore, to control this spinel reaction in the matrix, it is necessary to control the content of each component, especially the content of MgO, which is critical. If the MgO content is too high, in addition to the spinel reaction, it also has a large linear change rate, resulting in volume expansion, which will also promote spalling. Generally, the content of magnesia is controlled at about 10% (mass fraction), and the effect is better.

Pouring construction also has an impact on the occurrence of spalling. In this regard, the amount of water added must be strictly controlled and uniform vibration must be achieved. If the amount of water added is too large and the green body vibrates unevenly, the porosity will increase, and steel drilling will easily occur during use, causing the wall of the bag to peel off.

(3) The slag line erodes quickly

Due to the complex composition of steel slag, it is easy to react chemically with the castables, causing the castables in the slag line to be prematurely corroded, resulting in the slag line and the wall being unable to be used simultaneously. This is also a problem encountered in actual use. On the premise of significantly increasing costs, some methods are adopted:

① Specially configured slag line material is used for pouring the slag line parts. The raw materials of slag strand materials are improved to a higher level. For example, the bauxite powder uses high-quality high-alumina bauxite clinker with ω (A1203) = 86% and a bulk density of >3.2g/cm3.
② Add some pre-synthesized aluminum-magnesium spinel to the slag strand material and use a high MgO ratio, which can improve the ability to resist alkaline slag.
③ Reduce the dosage of active silica fume and control it to around 1.0% (mass fraction).
④Strictly control the amount of water added and vibrate evenly during pouring. Through these measures, the lifespan of the slag line and the package wall is basically synchronized.

Measures and Methods for Efficient Use of Aluminum-Magnesium Spinel Castables

①Retarding technology is one of the key technologies in the construction of magnesium-aluminum castables. According to changes in seasons and ambient temperature, retarders such as lignosulfonate should be added in a timely manner to make the setting time meet the needs of pouring construction.
② Adding some oversized aggregate and zircon powder to the castable is very beneficial to inhibit the occurrence of cracks.
③ The slag line uses a high MgO ratio and adds some pre-synthesized aluminum-magnesium spinel powder to improve the slag erosion resistance of the slag line.
④ During pouring construction, strictly control the amount of water added and vibrate evenly, which is of great significance to increase the service life of the castables.

To ensure the efficient and long-life operation of the ladle lining, it is not only necessary to purchase high-quality aluminum-magnesium spinel castable products, but also strictly follow the construction instructions and adjust the formula of the aluminum-magnesium spinel castable according to the actual construction conditions. Rongsheng unshaped refractory material manufacturers can customize the formula of refractory castables according to the actual working conditions of customers. To improve the service life of high-temperature furnace linings and save production costs for enterprises.

Application of Micro-Expansion Wear-Resistant Refractory Plastic in Power Plant Boilers

September 17, 2024 by rsrefractorycastable

Micro-expansion refractory plastic is made of water glass as a binder and sodium fluorosilicate as a coagulant. It was originally used in wall-through pipes of pulverized coal furnaces. It has the characteristics of strong plasticity at room temperature, strong adhesion, high fire resistance, good sealing performance, and convenient construction. It has high strength after natural drying, and its volume can expand slightly at high temperatures. It can be widely used in industrial kilns such as CFB boilers and pulverized coal furnaces, such as top wall-penetrating pipes, flame angles in the furnace, complex parts of the furnace wall, etc. It mainly plays a sealing role. Currently, this material can be used in boiler flues, chimneys, and other pipes containing acidic gases.

Micro-Expansion Wear-Resistant Plastic Refractory

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Micro-Expansion Refractory Plastic for Power Plant Boilers

With the continuous development of modern industry, the power industry plays an increasingly important role in people’s lives. As an important part of power plant boilers, the performance of the lining material has a great impact on the operating efficiency and life of the boiler. Therefore, the emergence of micro-expansion wear-resistant and refractory plastic has become an important lining material and is favored by power plant boiler manufacturers and maintenance engineers.

Micro-expansion wear-resistant refractory plastic has the characteristics of low thermal conductivity, high-temperature resistance, good thermal shock stability, wear resistance, corrosion resistance, and not susceptible to mechanical vibration. Its obvious feature is that under high-temperature conditions, the formation of an oxide layer can effectively protect the lining material, thereby extending the service life of the boiler. In addition, the micro-expansion properties allow the material to have better crack resistance and wear resistance at high temperatures, further improving the boiler’s operating efficiency and performance.

In the application of power plant boilers, micro-expansion wear-resistant, and refractory plastics are widely used in lining materials, patch materials and supplementary materials. As a lining material, it replaces traditional hard materials and can reduce the noise and vibration of the boiler and extend the life of the boiler. Patch materials are often used for boiler lining repairs and will not peel off the base material or affect thermal conductivity during the repair process. Supplementary materials refer to adding micro-expansion wear-resistant refractory plastic to the lining of the boiler to improve overall performance and life.

In short, the application of micro-expansion wear-resistant and refractory plastics in power plant boilers has become a trend. It is known for its high performance and excellent fire resistance. The range of applications is getting wider and wider. In the future, we believe that this material will play a more important role in the power industry and continue to provide a strong guarantee for the operating efficiency and performance of boilers.

Rongsheng Micro-Expansion Plastic Refractory Manufacturer

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How to Identify Refractory Plastic and Refractory Clay

Refractory plastics are made of refractory aggregates and powders, raw clay, chemical composite binders, and admixtures, which are mixed and extruded into brick shapes. Refractory materials that still have good plasticity after being packaged and stored for a certain period of time can be constructed using the tamping method. Commonly used bonding methods include chemical bonding, ceramic bonding, polycondensation bonding, etc.

Refractory mud, also known as refractory mud or joint material, is a joint material used for the masonry of refractory products. According to the material, it can be divided into clay, high alumina, silica and magnesia refractory clay. It is composed of refractory powder, binder, and admixture. Almost all refractory raw materials can be made into powders used to prepare refractory mud. Ordinary refractory clay, which is made from refractory clinker powder and an appropriate amount of plastic clay as a binder and plasticizer, has low strength at room temperature. Only when it forms a ceramic bond at high temperatures does it have higher strength. Chemically bonded refractory mud, which uses hydraulic, gas-hardening or thermo-hardening bonding materials as binding agents, hardens through a certain chemical reaction before the temperature drops below the temperature at which ceramic bonding occurs. The particle size of refractory mud varies according to the use requirements. Its limit particle size is generally less than 1mm, and some are less than 0.5mm or finer. When selecting the material of refractory mud, it should be consistent with the material of the refractory products of the masonry. In addition to being used as a joint material, refractory mud can also be used as a protective coating for the lining by applying or spraying.

Refractory mud properties and applications. 1. Good plasticity and convenient construction. 2. High bonding strength and strong corrosion resistance. 3. The refractoriness is relatively high, reaching up to (around 1650℃). 4. Good resistance to slag erosion. 5. Good thermal peelability. Refractory mud is mainly used in coke ovens, glass kilns, blast furnaces, and other industrial kilns.

Rongsheng Unshaped Refractory Material Manufacturer

Rongsheng Refractory Castable Manufacturer is a powerful manufacturer and seller of unshaped refractory materials. Rongsheng’s environmentally friendly, fully automatic unshaped refractory castable production line reliably guarantees the production and supply of refractory castables for high-temperature industrial furnaces. Rongsheng Refractory Castable Manufacturer already has customers in more than 120 countries, such as South Africa, Chile, Egypt, Colombia, Uzbekistan, Italy, Indonesia, Ukraine, Hungary, Spain, Kenya, Syria, Zambia, Oman, Venezuela, India, Peru, the United States, Ethiopia, etc. If you have the need to purchase unshaped refractory castables, or micro-expansion refractory plastics for power plant boiler maintenance, please contact us. Get free samples and quotes.

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Application of Different Types of Low-Cement Castables

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Advantages and Characteristics of Rongsheng High-Strength Low-Cement Castables

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The Use Temperature and Requirements of the Castables for the Ladles of Foundry

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Steel Ladle Castables Rongsheng Manufacturer

Performance Characteristics of Rongsheng Steel Ladle Castables

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Recommendations on the thickness of refractory castables in different application scenarios

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Suggestions for the construction and maintenance of refractory castables

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Refractory Materials for Heating Hood Lining

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Problems with Refractory Materials for Heating Hood Lining

Renovation Plan for Refractory Castable Materials of Heating Hood Lining

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How High a Temperature Can a Refractory Castable Withstand?

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Selection of Refractory Plastic Aggregates

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Effect of Clay and Powder Addition on the Performance of Refractory Plastic

Selection of Fire-Resistant Plastic Binder

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Factors Affecting Moisture Retention Performance

Influence of aggregate types

Influence of binder types

Effect of admixture types

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Refractory Castables for Furnace Lining

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High-Temperature Resistant Plastic Refractory for Furnace Lining

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Ramming Material Refractory for Furnace Lining

Causes of Damage to Refractory Castables for Furnaces and Methods of Repairing Castables

Surface crushing caused by alkaline impurities

Surface pulverization caused by carbonation reaction

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Repair of Furnace Lining Refractory Castables

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Insulating Refractory Castables for Ladles

Performance comparison of thermal insulation refractory castables for ladles

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In Conclusion

Rongsheng Refractory Castable Manufacturer

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Monomorphous Refractory Materials for Blast Furnaces

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Characteristics of Unshaped Refractory Materials Commonly Used in Blast Furnaces

The Use of Amorphous Refractory Materials in Blast Furnaces

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Application Methods of Unshaped Refractory Materials in Blast Furnaces

New water wall technology

Furnace lining injection technology

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Nano Silica Combined with Pouring Technology

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Application and Construction of Aluminum Magnesium Spinel Castables

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Problems and Solutions in the Construction of Aluminum-Magnesium Spinel Castables

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Problems and Solutions when Using Aluminum-Magnesium Spinel Castables

(1) Cracks.

(2) Peeling

(3) The slag line erodes quickly

Measures and Methods for Efficient Use of Aluminum-Magnesium Spinel Castables

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Micro-Expansion Refractory Plastic for Power Plant Boilers

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How to Identify Refractory Plastic and Refractory Clay

Rongsheng Unshaped Refractory Material Manufacturer

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