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Classification of Acid-Resistant Refractory Bricks and Their Applications in Different Industries

Release time:

2026-04-15 10:02

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Acid-resistant refractory bricks (also known as acid-resistant bricks or anti-acid bricks) are a type of specialized inorganic non-metallic material that combines high-temperature performance with exceptional resistance to strong acid corrosion. They are primarily manufactured through high-temperature sintering—at temperatures exceeding 1,380°C—to achieve a dense microstructure, with an acid resistance typically ranging from 95% to 99% and a low water absorption rate. These bricks are widely used as corrosion-resistant linings in industries such as chemical processing, metallurgy, and power generation.
Main Categories
There are numerous ways to classify acid-resistant and refractory bricks; the following are some of the most common classification criteria:
1. Classification by material/chemical composition (core industrial classification):
◦ Siliceous acid-resistant brick (silica brick): Its main component is SiO₂ ≥ 93%, classifying it as a strongly acidic refractory material. It exhibits excellent acid resistance (with an acid resistance of 99.8% or higher) but is susceptible to corrosion by alkaline substances. It also has a high load-softening temperature, making it suitable for high-temperature acidic environments.
◦ Clay-based acid-resistant bricks (clay bricks): With an Al₂O₃ content of approximately 30% to 48%, they are classified as weakly acidic refractories. They are relatively low in cost, exhibit good acid resistance and excellent thermal shock resistance; however, their water absorption is slightly higher, and their wear resistance and resistance to severe corrosion are somewhat inferior to those of other types.
◦ High-alumina acid-resistant bricks: Al₂O₃ content ≥48% (and even higher), classified as neutral or weakly acidic refractories. They exhibit high refractoriness (up to and exceeding 1750°C), good mechanical strength, excellent resistance to both acids and alkalis, and satisfactory thermal shock resistance.
◦ Other specialized types: such as silicon carbide, corundum, or composite acid-resistant bricks, used in more demanding high-temperature, highly acidic environments.
2. Classification by operating temperature/performance grade:
◦ Standard type: lower temperature resistance, suitable for moderate- to low-temperature acidic environments.
◦ High-performance type: high refractoriness (≥1650°C to 1700°C) and a load-softening temperature above 1300°C, making it suitable for service conditions with large temperature fluctuations.
Key Features
• Acid resistance: Exhibits strong resistance to strong acids such as sulfuric acid, hydrochloric acid, and nitric acid (including mixed acids), with high acid resistance and minimal corrosion.
• High refractoriness: Typically ranges from 1580°C to above 1770°C, making it suitable for use in high-temperature acidic atmospheres.
• Other properties: low water absorption, low porosity, relatively high mechanical strength (ambient-temperature compressive strength ≥ 30 MPa), good thermal shock resistance (for certain types), and high bulk density (approximately 1.8–2.5 g/cm³).
• Limitations: Generally resistant to strong alkali or high-temperature alkaline slags; the thermal shock resistance of certain types needs to be optimized based on the specific formulation.
Application Fields
Acid-resistant and refractory bricks are widely used in applications that require simultaneous resistance to high temperatures and acid corrosion, primarily as linings, flooring, or structural materials:
• Chemical industry: absorption towers, reaction vessels, acid storage tanks, acid channels, acid wells, heat exchangers, pipeline linings, and other equipment used in the production of strong acids such as sulfuric acid, hydrochloric acid, and phosphoric acid.
• Petroleum/Metallurgical Industry: Acid-resistant pipelines, storage tanks, and areas in blast furnaces or smelting equipment that come into contact with acidic slag.
• Power industry: linings for boiler chimneys, flues, and desulfurization systems (to resist acidic corrosion from flue gases).
• Other industries: papermaking, pharmaceuticals, synthetic fibers, juice processing, electroplating workshops, underground sewage pipelines, floor anti-corrosion applications, and more. It can also be used in acidic atmospheres, such as the cooling sections of glass furnaces.
In practical applications, the appropriate refractory type should be selected based on the specific service conditions, such as the type and concentration of acid, temperature fluctuations, and mechanical stress. For example, in high-temperature environments with strong acids, siliceous or high-alumina refractories are preferred; in cost-sensitive applications, clay-based refractories may be chosen. During installation, acid-resistant mortar or coating materials are often used in combination to ensure overall corrosion resistance.