Castable Refractory Plastic For High Temperature Applications

Aug 4, 2023

Castable refractory plastic is a type of cement-based formulation that contains refractory aggregates and inorganic binders. It can be manually shaped and molded or cast into molds to form durable insulating linings and repairs for high temperature furnaces, kilns and ovens.

ceramic fiber refractory paper

Key Attributes of Refractory Castable Plastic

• Fire resistant – Withstands extreme heat up to 1,800°C/3,272°F, depending on the specific plastic mix.
• Chemical resistant – Resists corrosion from acids, alkalis and salts when properly cured.
• Easy to apply – Can be easily troweled, sprayed or cast into place and manually shaped while still wet.
• Adheres well to surfaces – Bonds strongly to refractory linings, bricks and concretes once cured.
• Withstands vibration – Sets to form a rigid, shock-resistant ceramic structure.
• Low heat conductivity – Acts as an insulator to reduce heat loss from heated surfaces.
• Wear resistant – Holds up well over time due to ceramic aggregates within the mix.
• Economical – Provides a cost-effective alternative or supplement to refractory brick linings.

Types of Refractory Castable Plastic

Different types of castable plastic are available for specific uses:

• Low cement castable – Contains less binder for use up to 1,300°C. Often used as a repair mortar.
• Medium cement castable – Balanced formulation for applications up to 1,400-1,500°C. Common type for general use.
• High alumina castable – Made with aluminous cement for continuous use up to 1,700°C. Offers higher strength.
• Silicate binder castable – Uses sodium or potassium silicate as the binder, suitable for up to 1,300°C.
• Magnesia carbon castable – Contains magnesium oxide and carbon as filler, resistant to 1,800°C.

Applications For Refractory Plastic Castable Concrete

• Repairing refractory linings – Filling cracks, holes and joints to restore insulation and integrity.
• Insulating hot surfaces – Provides a cast insulation lining behind heated components like stacks and pipes.
• Patching oven floors – Repairing small holes and defects in industrial oven and kiln floors.
• Forming new furnace linings – Casting a plastic lining that is built up over time to form furnace walls.
• Creating thermal mass – Building up layers of castable plastic to absorb and slowly release heat energy.

Other Considerations About High Temperature Refractory Plastic Castable

• Working time – How long the castable remains workable before initial set. Usually 30-60 minutes.
• Curing time – Time before material achieves full strength, typically 24-48 hours.
• Cure temperature – Some plastics require being heated to 500-800°C to fully cure and develop strength.
• Permeability – Ability of gases and liquids to penetrate the refractory once cured affects its durability.
• Annual temperature cycles – Number of heating and cooling cycles the lining can safely withstand.
• Material safety data sheet – Review for safe handling, application and curing instructions.

Castable refractory plastic offers a moldable, shapeable solution for insulating and lining high temperature furnaces, kilns, ovens and other industrial heating equipment. By understanding factors like temperature resistance, cure requirements, working time and chemical resistance, you can successfully select and apply castable plastic for durable, high performance linings and repairs.