1. High temperature resistance: Refractory castables can withstand extremely high temperatures encountered in industrial processes, such as steelmaking, cement production, and petrochemical refining. They retain their mechanical strength and structural integrity even at temperatures exceeding 1000°C (1832°F) or higher.
2. Thermal stability: Castables exhibit excellent thermal stability, meaning they can withstand rapid temperature changes without significant degradation. This property helps them resist thermal shock caused by sudden heating or cooling cycles, ensuring prolonged service life in demanding environments.
3. Chemical resistance: Refractory castables are formulated to resist chemical attacks from corrosive substances, molten metals, slags, and gases present in various industrial processes. They provide a barrier against chemical erosion and maintain their physical integrity, preventing penetration and damage to the underlying structures.
4. Versatility and shape adaptability: Castables offer the advantage of being highly adaptable to different shapes, sizes, and complex geometries. They can be applied by pouring, gunning, or troweling, allowing for customized linings in furnaces, kilns, ladles, and other refractory applications.
5. Low porosity and high density: Castables can be designed to have low porosity, resulting in high bulk density and reduced permeability. This characteristic enhances their resistance to gas and liquid penetration and improves their mechanical strength and thermal conductivity.
6. Easy installation and repair: Refractory castables can be easily installed or repaired using simple application techniques. They can be cast or gunned into place, enabling efficient lining installation, maintenance, or patching.
7. Good abrasion resistance: Some castables are engineered to have high abrasion resistance, making them suitable for applications where they come into contact with abrasive materials or mechanical agitation.
8. Thermal insulation properties: Certain castables are formulated to provide thermal insulation, effectively reducing heat loss and improving energy efficiency in furnaces, boilers, and other thermal equipment.
1. High-temperature furnace lining: refractory castables are widely used in the lining of various high-temperature furnaces, such as iron and steel smelting furnaces, aluminum electrolytic cells, glass melting furnaces, and reactors in petrochemical and chemical industries. They withstand high temperatures and are resistant to alkali metals, acid gases and molten substances.
2. High temperature storage equipment: refractory castables are also widely used in high temperature storage equipment, such as high temperature storage tanks, high temperature heat shields and heat treatment furnaces. These devices need to withstand high temperature conditions while maintaining good thermal insulation properties to prevent heat loss and ensure safe operation.
3. High-temperature pipelines and pipeline trapping: In high-temperature pipeline systems, refractory castables can be used to fill, repair or reinforce damaged parts of pipelines. They have good pressure resistance and wear resistance, and can withstand the impact of high temperature and gas flow.
4. Cushion and heat insulation layer: refractory castable can be used as a cushion or heat insulation layer to provide protection and heat insulation. For example, in industrial furnaces, they can be used as a protective layer for floors or walls, reducing heat conduction and heat radiation losses.
5. Heat treatment mold: Some refractory castables have good wear resistance and high temperature resistance, so they are often used to manufacture heat treatment molds. These molds are used in metal heating and cooling processes, are able to withstand high temperatures and mechanical stress, and provide the desired shape and surface quality.
Refractory castable is a high-temperature refractory material, which is often used in the lining, bottom plate and plugging of industrial furnaces and kilns. According to different material composition and performance characteristics, common refractory castables can be divided into the following categories:
1. High alumina castable: High-alumina castable is mainly composed of high-purity alumina particles, which has high strength, corrosion resistance and high temperature resistance. It is suitable for ferroalloy smelting furnaces, electric furnaces, glass kilns, etc. under medium and high temperature environments.
2. Portland castables: Portland castables are based on Portland cement or phosphate cement, adding refractory aggregates and other additives, and have good fire resistance and corrosion resistance. It is suitable for non-ferrous metal smelting furnaces, cement kilns, petroleum catalytic devices, etc.
3. Silicon carbide castable: Silicon carbide castable is mainly composed of silicon carbide particles, which has extremely high temperature resistance and corrosion resistance, and is especially suitable for ultra-high temperature furnaces such as electric furnaces and high-temperature heat treatment equipment.
4. Phosphate castable: Phosphate castable is based on phosphate cement, adding refractory aggregate and other additives, which has good fire resistance and corrosion resistance. Suitable for high temperature equipment in metallurgy, chemical and ceramic industries.
5. High-temperature concrete: High-temperature concrete is composed of refractory aggregate, cement matrix and other additives, and has good high-temperature resistance and strength. It is suitable for the lining, bottom plate and plugging of some large industrial furnaces.
The selection of the appropriate refractory castable needs to consider a variety of factors, including the use of the environment, the physical and chemical properties of the refractory, construction conditions and budget. Here are some common choices:
1, the use of the environment: first of all, you need to understand the use of the environment, including temperature range, corrosive media, REDOX properties, etc. Different environments require different types of refractory castables.
2, the physical and chemical properties of refractory materials: refractory castable is usually composed of powder, polymer, additives and water, and its physical and chemical properties can be determined according to its composition. For example, aluminate castables have good resistance to high temperature, wear and corrosion. Silicate castable has excellent fire resistance and high strength. Magnesium aluminum castable has good alkaline resistance and corrosion resistance.
3, construction conditions: When selecting refractory castable, it is also necessary to consider construction conditions, such as pouring method, construction speed and construction amount. For the need for rapid construction, fast drying castable can be selected.
4, budget: Finally, according to the project budget and material prices and other factors to choose the appropriate refractory castable. Generally speaking, the price difference between different types of refractory castables is large, and it is necessary to weigh and choose according to actual needs.
Refractory castables used for heating furnace linings are typically selected based on the specific requirements of the furnace and the operating conditions involved. Here are some common types of refractory castables used for heating furnace linings:
1. Dense Castables: Dense castables are composed of high-density refractory aggregates and binders, resulting in a dense and strong material. They are suitable for areas of the furnace exposed to high mechanical and thermal stresses. Dense castables provide excellent resistance to abrasion, erosion, and thermal shock, making them ideal for applications such as burner blocks, furnace doors, and high-temperature zones.
2. Insulating Castables: Insulating castables are formulated to have low thermal conductivity, providing effective insulation for heat containment within the furnace. These castables are lightweight and offer thermal energy savings. They are commonly used in furnace walls and roofs to reduce heat loss and improve energy efficiency.
3. Low Cement Castables: Low cement castables contain reduced amounts of calcium aluminate cement (CAC), resulting in improved refractoriness and mechanical properties. These castables exhibit good strength and resistance to spalling at high temperatures. They are often used in areas of the furnace that experience moderate to high temperatures, such as hearths, soaking pits, and tundishes.
4. Ultra-Low Cement Castables: Ultra-low cement castables have an even lower content of calcium aluminate cement compared to low cement castables. This composition enhances their high-temperature stability and resistance to chemical attack. Ultra-low cement castables are employed in critical parts of the furnace, including hot spots, burner blocks, and areas with severe thermal cycling and corrosion conditions.
5. Self-Flowing Castables: Self-flowing castables, also known as pumpable castables, have a higher fluidity, allowing them to be easily poured or pumped into complex shapes and areas. They offer excellent installation convenience and are often used in intricate furnace linings, such as in coil windings or thin-walled structures.
Songlou Industrial Zone, Xinmi City, Henan, China