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Insulating Firebrick - Dirgodaz Amol Refractories Company
Insulating Firebrick

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General Description

Product Introduction

Insulating Fire Bricks (IFB) are lightweight products with very low thermal conductivity, used as thermal insulation layers in various high-temperature industries. These products are manufactured using advanced technologies and play a key role in optimizing energy consumption and improving thermal efficiency in industrial systems.

Dirgodaz Amol Refractories Company, leveraging global technical expertise and high-quality raw materials, produces various types of insulating firebricks (SD-B series) for maximum operating temperatures up to 1650°C, in compliance with international standards such as ASTM C155.

Production Process

These products are manufactured using high-purity raw materials with low iron oxide content, such as clays, aluminosilicates, alumina, and organic pore-forming agents, through a high-temperature sintering process. This production method results in high-quality components with stable structural and phase characteristics and a uniform porous microstructure, leading to excellent insulation performance and long service life.

Main production stages include:

  • Selection and preparation of high-purity raw materials
  • Precise mixing of materials in specified ratios
  • Controlled pressure molding
  • Drying in specialized kilns
  • Final high-temperature sintering
  • Rigorous quality control and standard testing

Key Advantages

  • Lightweight: Significant reduction in dead load of thermal structures
  • Low thermal conductivity: Excellent thermal insulation and energy savings
  • High thermal resistance: Stable performance at very high temperatures (up to 1650°C)
  • Long service life: Reduced maintenance and repair costs
  • Easy installation: Precise dimensions and uniform structural quality
  • Thermal shock resistance: Withstands sudden temperature changes without cracking
  • Chemical stability: Resistant to corrosion in reducing and oxidizing environments
  • Dimensional stability: Very low thermal shrinkage over time

Technical Specifications

Physical and Mechanical Properties

  • High purity, low alkali and iron oxide content
  • Low thermal shrinkage and high dimensional stability
  • High thermal stability and low thermal conductivity
  • High compressive and flexural strength
  • Good thermal shock and spalling resistance
  • Precise dimensions and stable structural quality

Industrial Applications

Industry Specific Applications Recommended Grades
Chemical and Petrochemical Olefin units, methanol plants, reformers SD-23/1, SD-26
Ferrous Metals Direct reduction furnaces, pelletizing, steel, cast iron SD-25/2, SD-28/S, SD-30
Non-Ferrous Metals Aluminum and copper melting furnaces SD-20/2, SD-25/1
Ceramics Industry Kilns for tiles, porcelain, glass, cement SD-23/2, SD-26, SD-28

These products are used as direct insulating refractory layers or as backup insulation in combination with other refractory materials in high-temperature industrial units.

Standard Dimensions

These products are precisely cut to the following standard sizes. Other dimensions for creating various arch shapes are also available. Tight dimensional tolerances ensure a more integrated insulating refractory layer and reduce heat loss through joints.

Hanging ceiling bricks in dimensions 230×152-178×76 and 230×172-152×76 mm are available for applications such as ceramic kilns.

Length (mm) Width (mm) Thickness (mm)
230 114 64-76
230 172-178 76
230 124 64-76

Standard Grades

Standard grades are designed for temperature ranges from 1260 to 1650°C and comply with international standards such as ASTM. These grades are suitable for general applications across various industries.

Standard Bricks (Operating Temperature Range: 1260 to 1650°C)

Grade Standard Service Temp.
(°C)		 Density
(g/cm³)		 Strength
(kg/cm²)		 Permanent Linear Change (%) Thermal Conductivity (W/m.K) Al₂O₃
(%)		 SiO₂
(%)		 Fe₂O₃
(%)
600°C 800°C 1000°C 1200°C
SD-23/1 ASTM C155 G23 1260 0.60 12 0.2 0.20 0.23 0.35 - ≥35 ≤60 ≤1
SD-23/2 ASTM C155 G23 1260 0.75 20 0 0.38 0.33 0.35 - ≥35 ≤60 ≤1
SD-26 ASTM C155 G26 1430 0.80 20 0.75 0.38 0.31 0.33 - ≥52 ≤43 ≤1
SD-28 ASTM C155 G28 1560 0.90 25 0.75 0.34 0.37 0.39 0.41 ≥65 ≤21 ≤1
SD-30 ASTM C155 G30 1650 1.05 30 1 0.42 0.45 0.47 0.50 ≥70 ≤26 ≤1

Chemical Properties

  • Aluminum Oxide (Al₂O₃): 25% to 70%
  • Silicon Dioxide (SiO₂): 21% to 70%
  • Iron Oxide (Fe₂O₃): ≤1% in all grades
  • Alkali Oxides (Na₂O+K₂O): ≤0.5%
  • Other Impurities: ≤4%

Special Grades

Special grades are designed for temperature ranges from 1200 to 1500°C with optimized chemical compositions. These grades are developed for specific applications with challenging operating conditions.

Special Grade Specifications (Operating Temperature Range: 1200 to 1500°C)

Grade Max Service Temp.
(°C)		 Density
(g/cm³)		 Compressive Strength
(kg/cm²)		 Permanent Linear Change (%) Thermal Conductivity Al₂O₃
(%)		 SiO₂
(%)		 Fe₂O₃
(%)
600°C
(W/m.K)		 1000°C
(W/m.K)
SD-20/1 1200 0.60 12 0.5 0.21 0.27 ≥25 ≤70 ≤1
SD-20/2 1200 0.80 16 0.3 0.29 0.27 ≥25 ≤70 ≤1
SD-25/1 1320 0.60 12 0.5 0.19 0.22 ≥38 ≤57 ≤1
SD-25/2 1320 0.75 20 0.2 0.27 0.32 ≥38 ≤57 ≤1
SD-28/S 1500 0.95 25 0.5 0.35 0.42 ≥55 ≤40 ≤1

Thermal Stability

All special grades have been tested for thermal stability under the following conditions:

  • 1200°C grades: 1170°C for 24 hours
  • 1320°C grades: 1290°C for 24 hours
  • 1500°C grade: 1470°C for 24 hours

Results: Linear change less than 0.5% in all grades