What are the differences in the usage methods of castables and refractory plastics?

Although castables and refractory plastics are both amorphous refractory materials, there are significant differences in their usage methods, mainly reflected in construction processes, types of binders, performance characteristics, and application scenarios. Here is a specific comparison between the two:

1、 Construction technology

castable refractory

Construction method: Casting or vibration molding is used, and water or other liquids need to be mixed to a liquid state before being poured into the mold or construction site, and compacted into shape through a vibrating rod.

Template requirements: High gloss templates need to be installed to prevent leakage, and the templates need to be coated with release agents or waterproof paint.

Maintenance requirements: After pouring, it needs to be cured with a mold for more than 24 hours. After demolding, it needs to be naturally cured for 24 hours. Before baking, it needs to be treated according to the heating curve.

Fire-resistant plastic

Construction method: Directly in the form of mud paste (without mixing) using tamping method (mechanical or manual), layer by layer paving (50-70mm per layer) and compacting.

Template requirements: The furnace wall usually does not require formwork support, and the furnace top requires hanging formwork; Temporary tire molds are required for the hole area.

Maintenance requirements: After tamping, the surface should be trimmed, air vents should be tied, plastic cloth should be covered to prevent dehydration, and cracks should be treated before baking.

2、 Adhesive and material status

castable refractory

Adhesive: Hydraulic (such as cement), air hardening (such as water glass), or fire hardening (such as phosphate), requires mixing with water to form a fluid slurry.

Status: Dry delivery, mixed with water during construction to form a flowing slurry with high fluidity.

Fire-resistant plastic

Adhesive: mainly composed of plastic clay (10% -25%), supplemented by plasticizers, and hardened by heating after bonding.

Status: Wet delivery (paste like), can be directly applied, has high plasticity, and does not harden after long-term storage.

3、 Performance characteristics

castable refractory

Advantages: Good fluidity, suitable for filling complex shapes; The strength at room temperature develops rapidly and has strong integrity.

Disadvantages: Weak thermal shock resistance, prone to cracking due to thermal stress at high temperatures.

Fire-resistant plastic

Advantages: Excellent thermal shock resistance, maintaining flexibility at high temperatures; Flexible construction, suitable for local repairs.

Disadvantages: Low strength at room temperature, requiring baking to obtain strength; The construction efficiency is relatively low.

4、 Application scenarios

castable refractory

Applicable scenarios: Large and complex masonry structures (such as heating furnace linings, boiler roofs), and parts that require rapid overall molding.

Fire-resistant plastic

Applicable scenarios: repair of furnace wall cracks, irregular parts (such as pipe bends), and local reinforcement in high-temperature areas (such as around burners).

5、 Other differences

Comparison item

castable refractory

Fire-resistant plastic

Water addition ratio

5%-8%

5%-10%

Construction efficiency

Use up within 15-30 minutes after stirring

Plasticity remains for a long time without strict time limits

price

lower

Higher (due to the cost of clay and plasticizers)

Baking requirements

Strictly bake according to the curve to prevent bursting

Before baking, it is necessary to tie exhaust holes to prevent cracking

summary

The core difference between castables and refractory plastics lies in their fluidity versus plasticity. The former is suitable for mechanized and rapid construction, while the latter is more suitable for manual repair and irregular parts. When choosing, it is necessary to comprehensively consider construction efficiency, cost, and working condition requirements.