Refractory bricks, as the most common refractory material in high-temperature industries, are widely used in metallurgy, building materials, power, chemical, and kiln engineering. In actual engineering construction, the selection of refractory brick specifications and dimensions is crucial, affecting not only the quality of masonry but also directly related to the operational stability and lifespan of the kiln. This article will provide a detailed introduction from four aspects: refractory brick specifications, classifications, characteristics, and selection guidelines, offering reliable reference for engineers.

I. Commonly Used Refractory Brick Specifications and Dimensions (Standard Sizes)

Currently, the industry commonly uses the following standard refractory brick sizes (in mm):

1. Standard Refractory Brick Size (230×114×65mm)

This is the most common size both domestically and internationally, also known as "standard brick" or "T3 brick." Its advantages include convenient construction, strong versatility, and suitability for most industrial kiln masonry.

2. Commonly Used Series Sizes

To meet the masonry needs of different parts, refractory bricks have been developed in various specifications, including:

Name Specifications (mm) Applications

T1 Brick 230×114×40 Used for thin-walled insulation and patching

T2 Brick 230×114×52 Commonly used in transition areas

T3 Brick 230×114×65 Most commonly used standard brick

T38 Brick 230×114×75 Thickened brick, improving wear resistance

T39 Brick 230×114×90 Furnace bottom or load-bearing parts

Arc-shaped Brick (Multiple Models) Customized according to radius Used for circular furnace walls and flues

Wedge-shaped Brick (Wedge Brick) Different top/bottom widths Suitable for arched roofs and curved masonry

In addition, large kilns often use custom-made bricks, such as 300×150×75mm and 345×150×100mm. Used for specific working surfaces or high-stress components.

II. Classification and Applications of Refractory Bricks

Based on different materials, refractory bricks can be divided into the following categories, each with its own characteristics and uses:

1. High-alumina bricks

Al₂O₃ content: ≥48%

**Characteristics:** High compressive strength, strong slag resistance

**Applications:** Iron and steel smelting, high-temperature furnace linings, glass kilns

2. Clay bricks

**Characteristics:** Economical price, good stability, easy construction

**Applications:** General industrial boilers, hot blast stoves, flues

3. Silica bricks

**Characteristics:** Strong acid resistance, good thermal shock resistance

**Applications:** Coke ovens, glass furnaces, acidic furnace linings

4. Magnesia bricks (magnesia-based bricks)

**Characteristics:** Strong alkali resistance, high-temperature resistance without deformation

**Applications:** Steelmaking converters, electric furnace bottoms

5. Insulating Bricks (Lightweight Refractory Bricks)

**Features:** Low thermal conductivity, lightweight

**Applications:** Kiln insulation layer, outer protective layer

Rational selection of materials and specifications is crucial for ensuring kiln lifespan and efficiency.

III. Key Factors in Refractory Brick Specification Selection

During engineering design and construction, the following factors should be considered when selecting refractory brick specifications:

1. Kiln Structure and Masonry Form

Circular kilns often use curved and wedge-shaped bricks; straight-walled structures primarily use standard bricks. For arched roof construction, the brick shape must be accurately calculated based on the curvature.

2. Operating Temperature and Environment

High-temperature (>1500℃) conditions require the selection of high-alumina bricks, magnesia bricks, and other high-performance materials.

Wear-prone areas require thicker bricks (e.g., 75mm, 90mm).

3. Construction Ease and Stability

Using bricks of uniform specifications whenever possible improves construction efficiency and overall masonry strength.

4. Cost and Material Supply

Standard refractory bricks are readily available and inexpensive; while custom-made bricks better meet specific needs, they have longer manufacturing cycles and higher costs.

IV. Refractory Brick Selection Recommendations (Practical Engineering Guide)

Prioritize Standard Sizes: 230×114×65mm offers the best versatility and compatibility with various supporting materials.

Check Product Specifications and Production Qualifications: Including compressive strength, refractoriness, chemical composition, and water absorption rate.

Customize Special Brick Shapes Based on Furnace Type: For example, special-shaped bricks must be used for arches, corners, and curved surfaces to ensure structural safety.

Choose Reputable Manufacturers: Factories with ISO and production license certifications should be able to provide test reports and factory certificates.

Sample Brick Trial Installation: Large-scale projects should conduct on-site trial installations to ensure that the size, shape, and construction conditions match.

Summary

Refractory bricks come in various specifications, from standard to custom-made, and play an important role in industrial furnaces. Appropriate specification selection can not only improve the strength and durability of the furnace but also reduce maintenance costs and increase production efficiency. Whether it's purchasing or engineering design, the specifications, dimensions, material types, application environment, and construction methods should all be considered comprehensively to achieve the best results.