Low-heat-conductivity magnesia-hercynite brick used for cement rotary kiln and production method thereof

Abstract

The invention discloses a low-heat-conductivity magnesia-hercynite brick used for a cement rotary kiln and a production method thereof. According to the invention, external temperature of a kiln body is reduced, and the effects of energy conservation and emission reduction are achieved. The magnesia-hercynite brick comprises the following components: high-purity magnesia or fused magnesia with a size of 3 to 1 mm, high-purity magnesia or fused magnesia with a size of 1 to 0 mm, high-purity magnesia or fused magnesia with a size of less than 0.088 mm, fused hercynite or sintered hercynite with a size of 2 to 0 mm, chemical fiber, and paper-pulp waste liquor with a concentration of 4 to 5%. The method comprises the following steps: material preparation, mixing and grinding, press molding into a green body, drying, and high-temperature sintering. According to the invention, uniform fiber micropores can be remained at a relative position in an internal structure of the magnesia-hercynite brick, so a gas-solid interface in the structure of a brick is increased; phonon dispersion of heat conduction of a solid phase is enlarged; heat conductivity of the brick is effectively reduced; and heat loss in a kiln is decreased.

Description

technical field [0001] The invention relates to a refractory material and a production method thereof, in particular to a magnesium-iron-aluminum spinel brick with low thermal conductivity for a cement rotary kiln and a production method thereof. Background technique [0002] The hexavalent chromium produced by the magnesia-chrome bricks used in the firing zone of the cement rotary kiln during the use and storage of discarded bricks has caused serious harm to the environment. The development of chromium-free refractory materials for the firing zone of the cement rotary kiln has become a research topic in the field of refractory materials. focus. The chromium-free products currently developed mainly include: magnesia spinel brick, dolomite brick, magnesia-zirconium brick and magnesia-iron-aluminum spinel brick. Through the long-term research and use of the above-mentioned products, it is found that the magnesia-iron-aluminum spinel brick has excellent high-temperature perfor...

AI Technical Summary

Problems solved by technology

[0003] In the process of use, it was found that the magnesium iron aluminum spinel brick has the disadvantage of high thermal conductivity

On the one hand, the high thermal conductivity of cement rotary kiln kiln lining refractory material causes the external temperature of the kiln body to rise, causing the steel structure of the kiln body to easily deform during operation, and serious cases will cause kiln shutdown accidents; High thermal conductivity will cause a large amount of heat loss in the kiln, resulting in waste of energy

In view of the high thermal conductivity of magnesia-iron-aluminum spinel bricks, researchers focused on reducing the thermal conductivity of materials on the optimization of materials, such as preparing iron-aluminum with lower overall thermal conductivity through the production process of composite bricks. For spinel bricks, this method has high production costs, low yield, and short service life due to easy breakage at the joints. At the same time, the effect of reducing the temperature of the kiln skin is not obvious

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