shaped refractories

At GAA-MinRef Canada Inc., we specialize in the design and manufacture of high-performance shaped refractory products, engineered to meet the demands of today’s most intensive industrial processes.

All refractory pieces are custom-designed and manufactured based on detailed customer drawings and usage conditions, ensuring optimal performance in service.We manufacture a wide range of shaped refractory parts tailored to our clients’ specifications and operational requirements 

Our company specializes in producing monolithic and precastrefractory components for Electric Arc Furnaces (EAFs), including delta and roof blocks, with unit weights of up to 16 tonsas , as well as complete sets of precast shapes for ladles and tundishes

Key Considerations in the Design and Casting of Refractory Shapes

1. Mold Design & Material Selection

  • Dimensional accuracy: Mold materials must retain shape under vibration and heat. Steel, wood, or high-strength resin boards are commonly used.
  • Draft angles and parting lines: Avoid sharp angles; use appropriate draft for de-molding.
  • Surface finish: Smooth mold surfaces minimize surface defects and sticking.
  • Thermal compatibility: Avoid using mold materials that expand/contract too differently from the castable.
 

2. Casting and Vibration Techniques

  • Vibration control: Uniform and adequate vibration reduces trapped air, voids, and segregation.
  • Flowability and workability: The castable formulation must allow even flow into complex shapes.
  • Avoid over-vibration: Can cause segregation of aggregates and weaken mechanical structure.

3. Drying and Curing Process

  • Controlled drying: Essential to prevent explosive spalling or microcracks.
  • Stepwise temperature increase: Use low-temperature hold (~110°C) to release free moisture, then ramp gradually to 300–600°C.
  • Curing: 24–48 hours at 20–25°C and >95% RH is standard for hydraulic binders.

4. Thermal Shock Resistance

  • Use of fibers: Addition of polypropylene or ceramic fibers enhances crack resistance during initial heating.
  • Graded aggregates: Broad particle size distribution improves packing and lowers porosity.
  • Addition of expansion joints in large shapes.

5. Mechanical Strength & Structural Design

  • Proper reinforcement: In large shapes, stainless steel anchors or mesh can be embedded.
  • Stress analysis: Use finite element analysis (FEA) to identify high-stress zones.
  • Shape optimization: Avoid sharp corners and stress concentrators.

6. Material Properties and Formulation

  • Low cement castables (LCC) and ultra-low cement castables (ULCC) are preferred for higher density and strength.
  • Dispersing agents: Polycarboxylate or citrate dispersants reduce water demand and enhance flow.
  • Nano-silica or colloidal silica bonding for better heat resistance.
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