UNSHAPED REFRACTORIES
Unshaped Refractory Series (Castables / Plastics / Ramming Mixes)
Formulations and installation methods are organized around service conditions, covering wear, corrosion, insulation, and rapid repair needs. Ranges are for selection discussion; supplied values are based on actual test results.
Combined solutions from raw material systems to installation methods
Product Overview
Unshaped refractories center on particle grading and a fine-powder matrix. Binders and dispersion systems control workability and service life, and the materials can be applied by casting, plastic forming, ramming, or gunning.
Typical areas: high-velocity erosion zones, rapid maintenance points, backup insulation layers, and high-temperature corrosion zones.
Optional reinforcement: steel or ceramic fibers to improve crack resistance and thermal shock stability.
Performance targets: balance high-temperature strength, wear resistance, and volume stability.
Installation targets: flowable/self-flow, plastic forming, or rammable fill to match site conditions and shutdown windows.
Series Matrix
Six typical formulations cover major service conditions
Select by strength, abrasion resistance, insulation, and rapid repair needs.
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High-strength wear series
High-alumina aggregate + ultrafine matrix focused on erosion and abrasion resistance.
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Phosphate-bonded wear series
Rapid setting at ambient/low temperature; suited for in-service quick repair.
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Alumina bubble castable
Lightweight high-temperature, low thermal conductivity, low linear change; suited for ultra-high-temp insulating load-bearing.
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Lightweight castable
Low density, low thermal conductivity; often used as backup or insulation layers.
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Low-cement self-flow castable
LCC/ULCC/SFCC, low CaO, high density, strong slag resistance.
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Ceramic fiber castable
Fiber reinforced, low heat capacity, suitable for lightweight insulating load-bearing.
Castables | Plastics | Ramming Mixes
High-strength wear series
Based on high-alumina aggregates and an ultrafine matrix with reactive Al2O3, microsilica, and dispersants to form a dense, low-porosity structure. Suitable for vibration casting, ramming, or gunning.
Product features: high room- and high-temperature strength, resistant to erosion and wear; low porosity and stable volume; optional steel fiber to improve thermal shock and crack resistance.
Typical applications: reheating furnaces, soaking pits, slideways, tuyeres, throats, high-velocity erosion zones, and wear-prone parts in CFB boilers.
Typical ranges: bulk density 2.6-2.9 g/cm3; CCS after 110C drying >=70 MPa, at 1000C >=80 MPa.
Abrasion loss <=6-8 cm3; PLC (1400C x 3 h) -0.5 to 0.5%.
Castables | Plastics | Ramming Mixes
Phosphate-bonded wear series
A dense high-alumina system using phosphoric acid or phosphate solution as the binder. Rapid setting at ambient/low temperature, suitable for in-service quick repair.
Product features: short setting time and high early strength; excellent thermo-mechanical performance from 300-1000C; tolerates rapid heat-up with shorter outages.
Reducing or hydrogen-containing atmospheres require formulation evaluation.
Typical applications: rapid repair on hot-face erosion zones in petrochemical cracking and reforming furnaces; iron and steel troughs, furnace door frames, and burner surroundings.
Lightweight high-temperature insulating load-bearing
Alumina bubble castable
Uses alumina bubbles/hollow bricks as aggregate with high-alumina fines or reactive Al2O3 as the matrix to achieve lightweight high-temperature performance, low thermal conductivity, and low linear change.
Product features: max service temperature 1700-1800C; high refractoriness under load; low thermal conductivity; good thermal shock stability.
Typical applications: carbon black reactors, high-temperature laboratory furnaces, glass furnaces, and special metallurgy reactors as hot-face or backup layers.
Typical ranges: bulk density 1.6-1.9 g/cm3; thermal conductivity about 0.8-1.2 W/(m-K) at 1000C; CCS at 110C >=20 MPa.
Backup and insulation layer solutions
Lightweight castable
Uses mullite or lightweight porous aggregates (ceramsite, cenospheres, perlite, etc.) for low density and low thermal conductivity, serving as backup/insulation layers.
Product features: low bulk density, low thermal conductivity; monolithic cast lining with good gas tightness; acid/alkali corrosion resistance can be optimized by system.
Typical applications: backup layers of industrial furnaces, flues, and waste heat boiler insulation layers, used with dense working layers.
Typical ranges: bulk density 0.6-1.6 g/cm3; thermal conductivity 0.12-0.45 W/(m-K); CCS at 110C >=5-25 MPa.
LCC / ULCC / SFCC
Low-cement self-flow castable
An ultrafine matrix replaces most cement, significantly reducing CaO content. Water reducers enable self-flow/vibration dual workability, and firing improves density and corrosion resistance.
Product features: CaO content LCC 1.0-2.5 wt%, ULCC <1 wt%; good self-flow with long working window; high-temperature strength and slag resistance outperform conventional castables.
Typical applications: linings for high-temperature corrosion zones in steel and petrochemical units; permanent layers for ladles/tundishes; CFB boiler combustion chambers and highly abrasive kiln zones.
Low thermal conductivity and crack toughening
Ceramic fiber castable
Chopped ceramic fibers act as reinforcement, combined with lightweight aggregates and binders to form a fiber-reinforced system with low thermal conductivity and crack toughening.
Product features: low thermal conductivity and low heat capacity; thermal shock resistance with better crack resistance than pure lightweight castables.
Avoid HF, H3PO4, and strong alkali media.
Typical applications: heat treatment furnaces and reheating furnace backup monolithic insulation layers; lightweight load-bearing insulation around doors and access points.
Ranges are for selection discussion; supply based on measured curves
Typical parameter snapshot
| Category | Max service temperature (C) | Bulk density (g/cm3) | CCS 110C (MPa) | CCS 1000C (MPa) | Thermal conductivity W/(m-K) | PLC (%) |
|---|---|---|---|---|---|---|
| High-strength wear castable | 1500-1600 | 2.6-2.9 | 70-100 | 80-120 | 1.6-2.2 @1000C | -0.5 to 0.5 |
| Phosphate-bonded wear resistant | 1400-1600 | 2.5-2.9 | 40-90 | 60-100 | 1.6-2.1 @1000C | -0.5 to 0.5 |
| Alumina bubble | 1700-1800 | 1.6-1.9 | 20-50 | 25-60 | 0.8-1.2 @1000C | -0.5 to 0.5 |
| Lightweight castable | 1000-1500 | 0.6-1.6 | 5-25 | 10-30 | 0.12-0.45 @800C | -0.6 to 0.3 |
| Low-cement self-flow (LCC/ULCC) | 1500-1700 | 2.5-2.9 | 60-100 | 80-130 | 1.6-2.1 @1000C | -0.4 to 0.4 |
| Ceramic fiber castable | 1000-1400 | 0.8-1.3 | 5-20 | 10-25 | 0.15-0.35 @800C | -0.6 to 0.3 |
Ranges are for selection discussion; supplied values are based on measured curves.
Ensure forming quality and service life
Installation and dry-out notes
- Strictly control water addition and flow/self-flow value; match forming method and vibration parameters to the formulation.
- Use staged drying and heat-up to avoid explosive boiling and steam spalling; phosphate systems allow faster heat-up but still require controlled ramp rates and soak times.
- Low-cement self-flow (LCC/ULCC) requires thorough dehydration and initial sintering to reach target strength and slag resistance.