Magnesium aluminum spinel three-layer composite brick and its preparation method

Abstract

The invention puts forward a magnesium aluminum spinel three-layer composite brick with good wear resistance, high refractoriness, great structural strength as well as good thermal insulating performance, and its preparation method. The composite brick realizes the integrated fireproof and thermal insulating functions of composite bricks, and improves the energy saving effects of rotary kilns. The magnesium aluminum spinel three-layer composite brick of the invention comprises a heavy working layer prepared from a magnesium aluminum spinel material, a lightweight thermal insulating layer prepared from fused hollow balls, and a transition layer located between the heavy working layer and the lightweight thermal insulating layer and prepared from spinels or magnesium-aluminum-chromium or magnesium-aluminum-titanium or magnesium-spinel-zirconium. The magnesium aluminum spinel three-layer composite brick provided in the invention introduces the transition layer, and can avoid reaction between the heavy working layer and the lightweight thermal insulating layer, so that the product can have good fireproof and thermal insulating effects without reducing the service life of materials, thus playing a role in saving energy consumption, lowering material consumption and reducing refractory material consumption of rotary kilns, and effectively prolonging the service life of equipment.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and in particular relates to a magnesium-aluminum-spinel three-layer composite brick and a preparation method thereof. Background technique [0002] With the continuous emergence of new technologies for cement production, the main equipment of cement production is developing in the direction of large-scale, increasing production, improving quality, saving energy, reducing consumption, and reducing costs have become the key to increasing efficiency in production management. Most of the existing refractory bricks and heat insulation bricks are made of a single material. When using them, bricks with various properties need to be used together. If they are used on relatively fixed equipment, such as tunnel kilns and downdraft kilns, they can meet the requirements. , but on some relatively moving equipment, such as a rotary kiln, it is difficult to meet the requirements when used together...

AI Technical Summary

Problems solved by technology

Most of the existing refractory bricks and heat insulation bricks are made of a single material. When using them, bricks with various properties need to be used together. If they are used on relatively fixed equipment, such as tunnel kilns and downdraft kilns, they can meet the requirements. , but on some relatively moving equipment, such as a rotary kiln, it is difficult to meet the requirements when used together

Some manufacturers and research units have conducted research and research on this, and have introduced some composite bricks that combine heavy materials and light materials. However, due to the low structural strength of the light parts, they cannot meet the requirements for use, and the The light part is easy to react due to material problems, which affects product performance and use effect, so it has not been widely promoted, and heavy bricks are still the main ones

[0003] Taking the 10,000t / d rotary kiln of Conch Group as an example, spinel bricks are used in the front transition zone, and magnesia-chrome bricks are used in the firing zone. Due to the large thermal conductivity of spinel bricks in the front transition zone and magnesia-chrome bricks in the firing zone (≥ 2.7W / m·K), so that the temperature of the outer wall of the kiln shell is relatively high (about 380°C, and it can reach 420°C at high temperature), which will increase the heat dissipation of the kiln shell on the one hand, thereby increasing the heat consumption of clinker. It will cause an increase in the unit cost of clinker; on the other hand, it is very easy to cause the cylinder to expand due to heat, resulting in an increase in the temperature of the supporting wheel in the middle of the kiln, especially in the later period of use or in summer, which will bring great hidden dangers to the normal operation of the equipment.

The overheating of the cylinder increases the damage probability of mechanical equipment and accelerates the deformation of the cylinder, and the deformation of the cylinder accelerates the mechanical damage of the inner lining. The result is brick falling and kiln shutdown, which affects the operation rate of the cement rotary kiln

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