Low Cement castable Archives - Rongsheng Refractory Castable Cement for Sale Manufacturer and Supplier

Cost-Effective Low-Cement Castable with Excellent Thermal Shock Stability

July 10, 2024July 9, 2024 by rsrefractorycastable

Low cement castable is one of the most widely used castables in thermal kiln linings, with Cost-Effective performance and easy construction. Low-cement castables have the advantages of less water addition, high density, good volume stability, and high strength at high temperatures. However, low-cement castables have poor air permeability and poor thermal shock resistance at high temperatures. When the castable is baked after being demolded, the low-cement castable is prone to bursting, peeling, peeling, etc. In severe cases, it may even damage the entire kiln lining. Therefore, how to improve and enhance the explosion-proof performance of low-cement castables is of great significance to the large-scale application and development of low-cement castables.

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How to Increase the Explosion-Proof and Thermal Shock Stability of Low-Cement Castables?

Rongsheng castable manufacturer, in order to improve the explosion-proof properties of low-cement castables, uses the method of adding explosion-proof fibers to low-cement castables to increase the permeability of the castables. The addition of explosion-proof fiber significantly improves the explosion-proof performance of low-cement castables. After the explosion-proof fiber is added to the castable, the explosion-proof fiber will shrink and melt when the castable is heated and baked after demoulding. Elongated pores are formed in the castable, increasing the opening vents inside the castable and improving the air permeability of the castable. This accelerates the discharge of water vapor, thereby improving the burst resistance of the castable and improving the explosion-proof performance of the castable.

The overall strength of low cement castables is very high at high temperatures. However, in some thermal kilns that work intermittently, frequent shutdowns and restarts will affect the service life of the low-cement castable working lining. In the case of rapid cooling and heating, it is very easy for the castable lining to peel off and crack, affecting the service life of the low cement castable.

Rongsheng Unshaped Refractory Castable Manufacturer, adding a certain amount of silicon carbide to low-cement castables will significantly improve the thermal shock stability of low-cement castables when facing rapid cooling and rapid heating conditions. However, the amount of silicon carbide incorporated needs to be strictly controlled. Because silicon carbide has a high thermal conductivity, when too much silicon carbide is added, the overall thermal expansion coefficient of low cement castables will increase, which is detrimental to the thermal shock stability of low cement castables. Castable manufacturers strictly control the amount of silicon carbide added to optimize the thermal stress of low-cement castables caused by excessively high thermal conductivity of silicon carbide. Only then will the low-cement castables have the best thermal shock stability when subjected to thermal shock. .

Whether low-cement castables need to improve their explosion protection or thermal shock stability, a comprehensive analysis needs to be made based on the working environment, operating temperature, erosion conditions, etc. of the thermal kiln. Then, make a reasonable formula based on the actual use needs of the enterprise’s kiln. The refractory material industry is an industry with very strong practical applications. There is no perfect refractory material. You can only find the most suitable refractory material based on the actual situation.

Rongsheng Low Cement Silicon Carbide Castable (Al2O3-48%,SiC-30%) — Rongsheng Silicon Carbide Low Cement Castable

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Silicon Carbide Composite Refractory Castable

What happens when silicon carbide is added to low-cement refractory castables? That turns into silicon carbide low cement castable!

The biggest feature of silicon carbide castable is wear resistance, followed by strong corrosion resistance. Its technological feature is that based on the process of refractory castables, a certain proportion of silicon carbide is added to form a composite refractory castable.

Because silicon carbide has strong wear resistance, adding it to refractory castables can improve the wear resistance of the castables. Moreover, the wear resistance coefficient of the castable is reduced, and the service life can be increased by 1 to 2 times. Silicon carbide has high thermal conductivity and small thermal expansion coefficient. Adding an appropriate proportion can increase the thermal shock resistance of the castable, and the thermal shock resistance of the castable is also relatively good. Especially for silicon carbide combined with silicon nitride products, the thermal shock resistance will be increased by 2 times compared to the thermal shock of the castable before adding it. It also prevents slagging or skin formation on the surface of the castable.

However, refractory castables with high silicon carbide content have high thermal conductivity, and the disadvantage of silicon carbide castables is that they are easily oxidized. Manufacturers add metallic silicon powder to the castable to inhibit the oxidation of silicon carbide. Castables combining silicon nitride with silicon carbide have lower oxidation resistance. Because the base material of silicon nitride combined with silicon carbide castable is in the form of interwoven fibers, it has high air permeability and plays a small protective role on silicon carbide particles. In silicate-bonded and silicon oxynitride-bonded silicon carbide products, the surface of the silicon carbide particles is wrapped by a continuous base material. Therefore, it has strong antioxidant properties.

Silicon carbide castables can maintain high strength and wear resistance at high temperatures, and have good chemical stability and will not be eroded by acid and alkali solutions. In addition, the wetting angle of silicon carbide with molten metal and slag is large. It has good corrosion resistance to various furnace lining solids, liquids and gases.

Rongsheng Unshaped Refractory Castable Manufacturer

Rongsheng Unshaped Refractory Castable Materials Manufacturer is a powerful manufacturer of refractory materials production and sales. Our environmentally friendly, fully automatic unshaped refractory material production line ensures the smooth delivery of unshaped refractory materials. Moreover, our professional technical team can customize the refractory castable formula according to the actual working conditions of the kiln lining to ensure the long service life of the refractory lining. Contact us to get free samples and quotes.

Castable Low Cement Lining With Silicon Carbide

July 2, 2024 by rsrefractorycastable

Low cement silicon carbide refractory castable is a special refractory material. Made of low cement ratio, silicon carbide aggregates and powders, ultrafine powder, CA-70 cement and antioxidants. It is suitable for thermal equipment such as power generation boilers, non-ferrous metallurgical furnaces and incinerators. It has low linear expansion coefficient, high thermal conductivity, high strength and good wear resistance. Low-cement silicon carbide refractory castables can improve the fire resistance and thermal efficiency of the equipment under reasonable proportions and use under appropriate conditions, and the application effect is good.

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Low Cement Silicon Carbide Refractory Castable

Low cement silicon carbide refractory castable is a special refractory material suitable for thermal equipment such as power generation boilers, non-ferrous metallurgical furnaces and incinerators. This silicon carbide refractory castable has the following characteristics:

Low coefficient of linear expansion. As the main refractory aggregate and powder, silicon carbide has a low coefficient of linear expansion, which can reduce the possibility of thermal stress.
High thermal conductivity. Silicon carbide has good thermal conductivity and can effectively conduct heat and improve the thermal efficiency of the equipment.
High strength. The use of low cement ratio and reasonable binder can improve the strength of the castable and increase its compression and flexural resistance.
Good wear resistance. Due to the use of silicon carbide with SiC greater than 97% as refractory aggregate, the castable has excellent wear resistance.

Low Cement Silicon Carbide Castable in RS Factory

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Raw Material Composition of Low Cement Silicon Carbide Refractory Castable

The preparation of low cement silicon carbide refractory castable includes the following ingredients:

Refractory aggregates and powders mainly use silicon carbide with SiC greater than 97%, which has excellent refractory properties.
Ultra-fine powder. Adding SiO2 ultrafine powder can improve the density and refractoriness of the castable.
Binder, using CA-70 cement as the binder, can ensure that the castable has a certain strength and durability.
Antioxidants. Metallic silicon antioxidants are used to prevent the oxidation of silicon carbide.

The performance test results of the castable at different temperatures are as follows:

After drying at 110℃, the bulk density is 2.5g/cm³, the compressive strength is 45MPa, and the flexural strength is 9MPa.
After firing at 1000℃, the linear change is -0.2%, the compressive strength is 107MPa, and the flexural strength is 24MPa.
After firing at 1450℃, the linear change is +0.3%, the compressive strength is 130MPa, and the flexural strength is 54MPa.
The thermal conductivity at 400℃ is 12.2W/(m·K).

In summary, low cement silicon carbide refractory castable has a low linear expansion coefficient, high thermal conductivity, high strength and good wear resistance. Through reasonable proportions and the use of appropriate materials, the fire resistance and thermal efficiency of the equipment can be improved. The castable has good application results in thermal equipment such as power generation boilers, non-ferrous metallurgical furnaces, and incinerators.

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Low Cement Mullite Corundum Castable

Low-cement mullite-corundum refractory castables use sintered or electro-fused mullite, brown corundum, alumina-based corundum and white corundum as refractory bone powder. Sometimes special-grade alumina clinker powder is also used, and ultra-fine powder is mixed with α-Al2O3 and silica fume. It is formulated with aluminate cement as binder and additional dispersant. This material is used for steel rolling heating furnace lining, water cooling pipe wrapping and burner bricks. The use effect is good on thermal equipment such as tundish slag weir, medium and small blast furnace tap trough and electric furnace cover.

Does Low Cement Castable Need to Add Steel Fiber when Used in Settling Chamber?

When low-cement castables are used in settling chambers, steel fibers are usually not required. When the design of the settling chamber is unreasonable, the discharge opening of the cone section is too small and the smoke dust needs to be beaten. At this time, steel fibers can be added to the low cement castable to enhance wear resistance and extend the service life. Under special circumstances, the settling chamber can be lined with clay bricks or high-aluminum castables with high-voltage electrical porcelain added.

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If low-cement castables are used in settling chambers, there is generally no need to add steel fibers.

If the lower opening of the cone section of the settling chamber is too small and needs to be beaten during use, just add steel fibers to the low-cement castable used in the cone section to increase traction, wear resistance, and erosion resistance. However, if the discharge port of the settling chamber is reasonable, and the size of the settling chamber and the rotary kiln are also reasonable, there is no need to add steel fiber to the castable.

The temperature of the settling chamber is not high, and it mainly plays the role of dust removal. The dust has fallen to the bottom before the flue gas flows out of the settling chamber, and is collected by the ash hopper at the bottom of the settling chamber. The unsettled dust is brought out with the flue gas. General low-cement castables can be used.

Generally, it is common to use high-aluminum castables and low-cement castables. However, clay bricks are also used as linings for settling chambers. There is also the use of high-aluminum castables with a certain proportion of high-voltage electrical porcelain added to the castables to create a glazed surface to facilitate the fall of smoke and dust.

Adding steel fibers to low-cement castables is rarely used in settling chambers. In recent years, the settling chambers of some white ash rotary kilns and zinc volatilization kilns are often lined with clay bricks. However, the size design of some settling chambers is not reasonable. If the settling chamber is too small, and the cone section discharge opening is also too small, there will be a situation of beating during the production process to make the smoke and dust sink. This will speed up the service life of the cone section lined with clay bricks or low-cement castables.

Therefore, under special circumstances, a reasonable proportion of steel fibers is added to the low-cement castable to increase the wear resistance of the cone section and extend its service life.

Low Cement Castable For Heating Furnace

June 16, 2021November 22, 2019 by rsrefractorycastable

Low cement castable refers to the refractory castable combined with calcium aluminate cement, the castable with CaO content less than 2.5%, and the castable with the content of calcium aluminate cement about 1/2 to 1/3 of that of ordinary calcium aluminate cement castable. Low cement castable characteristics outstanding, high quality, favorable price.

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According to the operating conditions of the heating furnace, the characteristics of the low cement castable used are described below.

1. Good thermal shock stability

The content of low cement castable Al2O3 is 55%-67%. After drying and firing at 1400℃, the compressive strength is 15-30mpa and 40-65mpa respectively. Compared with low cement castable with high aluminum content and strength, its thermal shock stability is better.

2. It has micro-expansibility

In the low cement castable add appropriate amount of expansion agent and materials containing aluminum and silicon, so as to produce micro-expansion when using, to prevent the formation of cracks.

3. Good sintering performance

By adding proper amount of sinter and other materials into the low cement castable, the working layer of the wall can be sintered and formed as a whole in the process of using at 1000-1350℃, so as to adapt to the working conditions of its double-sided heating.

In the low cement castable matrix, most of the calcium aluminate cement is replaced by superfine powder with the same or similar chemical composition as the main material of the castable. Therefore, this series of refractory castable is a kind of refractory with hydration and aggregation.

The low cement castable characteristics of prominent. After casting molding, less cement compounds are generated during curing, and there is no large amount of hydration bond damage during heating and baking, resulting in the decrease of strength at medium temperature.

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We are a professional refractory castable manufacturer, the production of low cement castable characteristics of remarkable, high quality, certification qualification complete, welcome to consult and purchase.

Low Cement Castable For Heating Furnace

June 16, 2021October 28, 2019 by rsrefractorycastable

The content of low cement castable Al2O3 is 55%~67%, and the compressive strength after drying and firing at 1400℃ is respectively 15~30MPa and 40~65MPa. Compared with low cement castable with high aluminum content and strength, its thermal shock stability is better. In the low cement castable with appropriate amount of expansion agent and materials containing aluminum and silicon, so as to use to produce micro-expansion, thus preventing the formation of cracks.

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The low cement castable used in the heating furnace can be sintered and formed as a whole in the process of using 1000~1350℃ by adding proper amount of sinter and other materials in the preparation process, which can adapt to the working conditions of double-sided heating.

This series of refractory castable has the advantages of high service temperature, good abrasion resistance, heat resisting shock, anti-spalling, good volume stability at high temperature and convenient construction. Widely used in heating furnace, soaking furnace lining, tundish lining, electric furnace top, iron ditch, RH lifting pipe, spray gun and so on.

Low cement refractory castable is mainly used in boilers, petrochemical industrial furnaces, metallurgical systems and low temperature thermal equipment.

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Zhengzhou Rongsheng Kiln Refractory Co.,Ltd. is high quality low cement castable manufacturer.In the production and manufacturing of refractory materials has a broad reputation, quality is excellent and reliable, focus on the production and manufacturing process, the products exported to more than 60 countries and regions in the world, the customer’s praise.