How to Choose Refractory Fire Bricks

Refractory fire bricks are crucial for fire protection in industrial kilns and buildings. Choosing the right products directly impacts safety, quality, and maintenance costs. This article provides key selection points for professionals from a core perspective.

1.Matching the Scenario to Needs is a Prerequisite

Industrial kilns require a focus on temperature and corrosion resistance: high-alumina or corundum bricks are selected for steel blast furnaces (above 1500℃); magnesia bricks are used in the firing zone of cement rotary kilns (alkaline environment); and silica bricks are selected for the regenerator chambers of glass kilns (requiring thermal conductivity and stability). Building fire protection emphasizes insulation and structural stability, commonly using clay or ceramsite lightweight refractory fire bricks that must meet the fire resistance limit requirements of GB 50016.

2.Mastering the Core Materials and Parameters

Main materials fall into four categories: clay bricks (Al₂O₃ 30%-48%, good thermal stability and low cost), high-alumina bricks (Al₂O₃ 48%-90%, high temperature resistance and high strength), magnesia bricks (MgO 80%-95%, strong alkali resistance), and silica bricks (SiO₂ ≥ 93%, good thermal conductivity and low coefficient of expansion). Key parameters to consider include: refractoriness (100-200℃ above operating temperature), room temperature compressive strength (≥ 20MPa for buildings, ≥ 50MPa for critical industrial components), and thermal shock resistance (≥ 50 water cooling cycles in frequent hot and cold environments).

3. Avoiding Selection Pitfalls

Avoid the misconception that “the more expensive the material, the better.” For example, clay bricks are sufficient for the transition zone (1300-1400℃) in cement kilns; blindly choosing expensive corundum bricks can easily lead to spalling. Also, avoid focusing solely on temperature resistance while ignoring other factors. Heat treatment workshops need to consider chemical properties such as resistance to carburization; otherwise, problems such as decreased strength and collapse may occur.

4.Three-Step Implementation Method

Scenario breakdown, clarifying requirements such as temperature, medium, and load.

Parameter matching, selecting materials according to requirements and verifying core indicators, prioritizing products that meet national standards.

Referencing application cases in similar scenarios to avoid discrepancies between laboratory performance and on-site results. Refractory fire brick selection must be scenario-centric and parameter-based, abandoning empiricism and price orientation to build a solid safety barrier.