Refractory bricks and ordinary bricks may look similar in appearance, but they differ significantly in performance, use, and manufacturing process. This article will explore the core differences between the two in terms of material composition, high temperature resistance, application scenarios, and production process.
1. Material composition: the essential difference in chemical formula
The core of refractory bricks lies in their high temperature resistant formula:
- Main raw materials: inorganic non-metallic materials such as alumina (Al₂O₃), silicon dioxide (SiO₂), magnesium oxide (MgO), and some silicon carbide (SiC) is added to improve thermal shock resistance.
- Additives: Clay, graphite or chromite as a binder to enhance structural stability.
- Porosity control: The pore distribution is adjusted by a foaming agent (such as the porosity of lightweight refractory bricks can reach 70%) to achieve a balance between insulation and high temperature resistance.
Ordinary bricks use traditional sintering processes:
- Basic materials: natural minerals such as clay, shale, coal gangue, etc., containing impurities such as iron and calcium.
- Forming method: The wet blank is pressed and dried naturally, and then sintered at 900-1100℃ to form a dense structure.
Key difference: Refractory bricks achieve high-temperature stability through high-purity raw materials and special additives, while ordinary bricks rely on the natural characteristics of clay sintering.
2. High temperature resistance: from 800℃ to 1800℃
The excellent performance of refractory bricks is reflected in their stability in extreme environments:
- Refractory classification: ordinary refractory bricks (1580-1770℃), advanced refractory bricks (1770-2000℃), special refractory bricks (＞2000℃)
- Thermal shock stability: can withstand more than 20 cycles of 1100℃→cold water quenching (taking magnesia-alumina spinel bricks as an example)
- Load softening temperature: ＞1300℃ (High alumina bricks can reach over 1500℃)
Performance of ordinary bricks at high temperatures:
- Safe use temperature: usually not exceeding 800℃
- Compressive strength drops by 40% at 600℃, and continuous high temperature leads to structural powdering
- Thermal expansion coefficient: about 5×10⁻⁶/℃ (refractory bricks are 2-4×10⁻⁶/℃)
Experimental data: After heating the two bricks in a muffle furnace at 1000℃ for 2 hours, obvious cracks appeared on the ordinary bricks, and the surface of the refractory bricks was only slightly oxidized.
3. Application scenarios: the inevitable choice of professional division of labor
Industrial main field of refractory bricks:
- Steel metallurgy: blast furnace lining, permanent layer of converter (service life 3-5 years)
- Cement industry: rotary kiln transition zone (need to resist 1400℃ high temperature and alkali erosion)
- Glass kiln: dense zirconium corundum bricks for pool walls, anti-glass liquid erosion > 5 years
- Garbage incinerator: silicon carbide bricks are used to resist acidic gas corrosion
Construction application of ordinary bricks:
- Load-bearing wall: compressive strength 10-30MPa (MU10-MU30 standard)
- Partition wall masonry: 240mm×115mm×53mm standard size
- Decoration project: clear brick wall grouting process, water absorption rate needs to be controlled at 16%-18%
Rongsheng Refractory produces various refractory bricks, insulation bricks, and castables. The quality and price are widely praised by old customers. Welcome to send us your quotation requirements. We have a professional technical team and sales team to provide perfect kiln solutions!