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Introduction to Refractory Materials Used in Lime Rotary Kilns

Release time:

2026-03-13 09:17

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The refractory materials used in lime rotary kilns are selected based on the different sections of the kiln, as the operating temperature, atmosphere, and stress conditions vary significantly from one section to another.

The preheating and drying zones of lime rotary kilns typically operate at temperatures ranging from about 800 to 1100°C. These areas are characterized by low temperatures, a moderately alkaline environment, and material preheating; therefore, clay bricks are commonly used, with some kilns also employing high-alumina bricks. These materials offer excellent thermal shock resistance and are relatively cost‑effective.

As you enter the transition zone, the temperature rises to around 1100–1300°C, and the materials begin to decompose. This section typically relies primarily on high-alumina bricks, with an alumina content generally ranging from about 70% to 80%. Occasionally, a small amount of low-cement, high-alumina castables are used in combination, as wear resistance and alkali resistance need to be further enhanced.

In lime rotary kilns, the critical calcination zone—also known as the burning zone—typically operates at temperatures ranging from 1,300 to 1,500°C, with localized peaks even higher. This is a region characterized by high temperatures, a strongly alkaline atmosphere, and relatively vigorous reactions. At present, magnesia–alumina spinel bricks are the mainstream choice; these bricks have become the standard configuration for both new construction projects and line renovation projects. They exhibit excellent alkali resistance, good dimensional stability, and strong resistance to ring formation. In the past, some older kilns used directly bonded magnesia–chromite bricks; however, due to environmental considerations, low-chromium or chromium‑free magnesia–alumina spinel bricks now dominate the market. For kilns with higher production capacities, even higher‑purity magnesia–alumina spinel bricks or magnesia–iron–alumina spinel bricks are often employed.

The cooling zone temperature drops rapidly from 1300°C to around 800°C, creating an environment characterized by rapid cooling and high abrasive wear. Therefore, high-alumina bricks (with an alumina content of over 70%) or corundum–mullite bricks are often used, as they offer excellent resistance to thermal shock and abrasion.

Local temperatures in the kiln head and burner areas may exceed 1500°C, with severe flame erosion and corrosion from pulverized coal or gas. High-alumina or corundum castables are commonly used here, along with spall-resistant high-alumina bricks; special-shaped bricks or castables are often required for repairs.

In addition, the entire kiln is equipped with an insulation layer to reduce the shell temperature, typically using lightweight high-alumina bricks, aluminum silicate fiber boards, or nanomicrobead insulation materials, often applied in multi‑layer composite configurations.

Clay brick,High-alumina brick,Magnesium alumina spinel bricks,Corundum-mullite brick

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