Application of Magnesium Iron Spinel Brick in Cement Kiln

Measures to reduce the chromium content in cement kilns consist mainly of replacing magnesia-chrome bricks with magnesia-dolomite bricks, magnesium-alumina spinel brick and magnesium-iron spinel brick. Best refractory material to replace magnesia-chrome bricks in cement kilns.

Why use magnesia-iron-spinel bricks instead of magnesia-chrome bricks?

Magnesia-chrome bricks cause public nuisance

The direct combination of magnesia-chrome brick is a refractory material with good processability and high cost for cement kilns. However, during use, the initially harmless Cr2O3 components in magnesia-chromium bricks combine with the alkaline components in the firing materials, which form water-soluble toxic Cr compounds 6+, that pollute the environment with chromium, which leads to, that magnesium chrome bricks are being thrown away by the cement industry. The direct combination of magnesia chrome brick is very suitable for the firing zone of cement rotary kiln, mainly because, that magnesia-chrome brick can form a protective shell for a furnace, and chromite is used to form the furnace shell, raw materials for magnesia-chrome bricks. The role of iron in the furnace lining is to participate in the formation of high-viscosity ferrites tetracalcium aluminate C, AF and other protective layers of furnace lining.

Magnesia spinel bricks are used in cement kilns

Thanks to the introduction of iron-aluminum spinel into magnesia refractory materials, The produced magnesia-iron-aluminium-spinel brick represents a new kiln lining concept for cement rotary kilns. Good design flexibility and excellent hanging characteristics of the furnace shell ensure high manufacturability. In recent years, magnesia iron-aluminum spinel bricks have been fully used in the high temperature zone of cement rotary kilns..

Characteristics of magnesia-iron composite spinel bricks

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During use, a layer of highly viscous calcium-iron compound or calcium oxide with aluminum and iron is formed on the hot surface of the brick., which improves the performance characteristics of the furnace shell and its strength, and is also suitable for protecting facing bricks and extending their service life.
● Iron-aluminum spinel alloy added to the product, which not only has high strength, but also excellent resistance to thermal shock. It can also effectively resist the chemical erosion of the liquid phase of cement clinker and alkali, sulfur and other gases.
● Thermal expansion of spinel and periclase during firing and cooling is not the same. Microcracks, formed between them, can soften the effects of stress, caused by temperature changes, and prevent brittle explosion of facing bricks.
● Chromium-free and environmentally friendly