Phosphate bonded bricks are high-performance specialty refractory materials made primarily from corundum (α-Al₂O₃) using phosphate chemical bonding technology, offering excellent refractory performance and special usage characteristics.Their Main Raw Materials Primarily composed of fused corundum, sintered corundum, or tabular corundum, with Al₂O₃ content typically above 90-99%. Binder System Uses phosphoric acid (H₃PO₄), aluminum dihydrogen phosphate [Al(H₂PO₄)₃], or aluminum monohydrogen phosphate [AlH₂PO₄] as chemical binders, with addition amounts typically 3-8%. Due to their features of high strength, outstanding thermal shock resistance, and corrosion resistance, they are ideal for high-temperature industrial furnaces, particularly in applications with frequent thermal cycling such as steel ladles, glass kilns, Aluminum electrolytic cells, copper smelting furnaces, etc.
Technical Data of Phosphate-Bonded Corundum Brick
|
Item |
|
|
Al2O3 ≥ |
95% |
|
Fe2O3 ≤ |
0.5% |
|
SiO2 ≤ |
1.5% |
|
CaO+MgO ≤ |
0.3% |
|
P₂O₅ |
2% - 8% |
|
Refractoriness≥ |
1790~1850℃ |
|
Apparent Porosity≤ |
12% - 18% |
|
Cold Crushing Strength |
60-150Mpa |
|
Rupture strenth |
10~30Mpa |
|
Bulk density ≥ |
3-3.4g/cm 3 |
|
0.2Mpa Refractoriness under load ≥ |
1700℃ |
|
Hot Modulus of Rupture(1600℃) |
20 - 50 MPa |
|
Thermal Shock Resistance,(1100℃,water cooling)≥ |
20 times |
|
Permanent Linear Change,(1600℃,2h) |
±0.2% - ±0.5% |
|
Thermal Conductivity, 800℃ |
2.5 - 3.5W/(m·K) |
|
Coefficient of Thermal Expansion,(20-1000℃) |
8.0 - 9.0 × 10⁻⁶ /℃ |
Features and Advantages
Phosphate-bonded corundum bricks inherit the excellent characteristics of corundum and combine them with the advantages of phosphate bonding, giving them outstanding features:
Extremely High Refractoriness and Load Softening Point
Due to their primary component being high-purity corundum, their refractoriness can exceed 1900°C, and their load softening point is also very high, ensuring structural integrity in ultra-high temperature environments.
01
Exceptional High-Temperature Strength and Creep Resistance
Even at extremely high temperatures, the brick maintains high strength and resists deformation under long-term loads.
02
Outstanding Wear Resistance
Corundum itself is an extremely hard material, giving phosphate-bonded corundum bricks excellent resistance to erosion and abrasion, making them particularly suitable for areas with severe material flow or gas erosion.
03
Good Thermal Shock Stability
Phosphate bonding provides the brick with a certain degree of toughness, allowing it to better resist cracking and spalling caused by sudden temperature changes.
04
High Ambient and Medium Temperature Strength
The phosphate binder forms high strength even without firing or with low-temperature baking, which facilitates transportation, installation, and initial furnace heat-up.
05
Excellent Chemical Corrosion Resistance
It offers strong resistance to acidic slag, alkaline slag, and molten metals, especially against the corrosion of certain specific media.
06
Good Volume Stability
It exhibits minimal volume changes at high temperatures, helping to maintain the integrity of the furnace lining.
07
Lower Production Energy Consumption
Compared to high-temperature sintered corundum bricks, the production of phosphate-bonded bricks does not require extremely high firing temperatures, resulting in relatively lower energy consumption.
08
Main Applications
Due to phosphate-bonded refractory bricks excellent comprehensive properties, phosphate-bonded corundum bricks are primarily used in critical areas that demand extremely high refractory material performance:
Iron and Steel Industry: Blast Furnaces,Ladle linings, RH furnace linings,refining furnaces, tundishes,Heating Furnaces,etc, leveraging high-temperature strength and thermal shock resistance. erosion and corrosion resistance and wear resistance.
Non-ferrous Metal Smelting: Aluminum electrolytic cells, copper smelting furnaces. linings of copper, lead, zinc, and other non-ferrous metals, resisting corrosion from molten metal and slag.
Petrochemical Industry: Widely used in reactor linings and regenerator linings of catalytic cracking units, utilizing excellent acid slag corrosion resistance.
Waste Incinerators: Incinerator linings must withstand complex high-temperature, corrosive, and abrasive environments.
Glass Kilns: Regenerator checker bricks in glass furnaces,Certain specific areas with high requirements for wear and corrosion resistance.
Ceramic Industry: Used in critical parts of high-temperature kilns, such as firing zones and cooling zones, High-temperature reactors, kiln furniture (shelves, posts).
Phosphate-bonded refractory materials are used for critical sections of high-temperature industrial furnaces.
Usage Precautions
Heating Schedule
Initial use requires strict adherence to heating curves, with slow heating in 200-400°C range to prevent thermal stress damage to phosphate bonding phases.
Chemical Environment
Avoid long-term use in strong alkaline environments, as aluminum phosphate is easily corroded under high-temperature alkaline conditions.
Thermal Shock Management
Despite good thermal shock resistance, avoid rapid temperature changes, especially during startup and shutdown processes.
Manufacturing Process
Raw Material Processing
Corundum materials require strict screening and iron removal to ensure purity. Phosphate binders need controlled concentration and purity.
Mixing and Forming
Using intensive mixers for 3-5 minutes mixing to ensure uniform dispersion. Forming pressure typically 100-200MPa using hydraulic or friction presses.
Drying Treatment
Formed blanks need drying at 110-150°C for 24-48 hours, controlling drying rate to prevent cracking.
Heat Treatment
Pre-heating at 400-600°C for 2-4 hours to allow full phosphate reaction for initial bonding. Some products require additional high-temperature treatment at 1000-1200°C.
Packaging and Shipping of Phosphate Bonded Bricks
Our Company
Why Choose Us?
We are a modern integrated enterprise specializing in refractory materials, combining R&D, production, design, construction and technical services. Our business covers development, manufacturing and sales of refractory materials and insulation material
Our engineers will recommend right bricks for you based on:
Operating temperature → Determines Al₂O₃ content
Chemical environment → Corrosion resistance grade
Mechanical load → Density & strength requirements
Free samples to be provided.
Within in 8 hours to respond your inquiry.
If you receive defective products,We guarantee:24-hour response,Solution within 48 hours and Replacement/refund options.
Our company supplies a complete range and type of Refractory High alumina brick, including:
Standard to high-grade products (Al2O3: 48%-90%)
Special-function types (spalling-resistant, low-creep, microporous, etc.)
Custom-engineered solutions for specific applications
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