Modified high-alumina brick for cold ends of calcining zone and transitional zone of cement kiln and method for preparing high-alumina brick

Abstract

The invention relates to a modified high-alumina brick for cold ends of a calcining zone and a transitional zone of a cement kiln and a preparation method of a high-alumina brick. The modified high-alumina brick comprises the following materials: 25-35 percent of tertiary alumina particles with granularity of 5-3mm, 15-25 percent of tertiary alumina particles with granularity of 3-1mm, 10-1 percent of tertiary alumina with granularity of 1-0mm, 20-35 percent of tertiary alumina fine powder with granularity of smaller than 0.088mm, 5-10 percent of primary alumina fine powder with granularity of smaller than 0.088mm, 3-5 percent of andalusite fine powder with granularity of smaller than 0.088mm, 0-6 percent of silicon carbide fine powder with granularity of smaller than 0.088%, 0-4 percent of soft clay with granularity of smaller than 0.088mm, and a binding agent which accounts for 3-7 percent of the gross weight of the above raw materials. The preparation method comprises the following steps: mixing and rolling the raw materials according to proportion, then ageing for 16-24h, pressing for shaping, introducing the shaped material into a kiln to be dried for more than 24h at the temperature of 120-140 DEG C, calcining at the firing temperature of 1300-1400 DEG C, and carrying out heat preservation for 6-8h to obtain the high-alumina brick. The modified high-alumina brick is reasonable in alkali resistance and thermal shock resistance and better in energy-saving and heat-insulating effects.

Description

Technical field [0001] The invention relates to the field of refractories, in particular to a modified high alumina brick for the cold end of a cement kiln decomposition zone and transition zone and a preparation method thereof. Background technique [0002] my country has abundant bauxite resources and ranks among the top in the world. Refractory products made of high alumina bauxite have already been used in cement kilns. However, the alkali enrichment effect of the new dry method cement kiln is obvious. Because of the high aluminum content of ordinary high alumina bricks, the alkali resistance often fails to meet the requirements, and its thermal shock resistance is also insufficient. [0003] At present, the commonly used silicon-moulded bricks often use a large amount of first-grade or even special-grade high alumina bauxite as raw materials, and add SiC with a mass ratio of 10-25%. The addition of SiC can improve the alkali resistance and thermal shock resistance of the pro...

AI Technical Summary

Problems solved by technology

The addition of SiC can improve the alkali resistance and thermal shock resistance of the product, but its shortcomings are also obvious

The high content of SiC is not only expensive, but also increases the sintering temperature of the product, which in turn causes more SiC burning loss during the firing process; in addition, the addition of SiC improves the thermal conductivity of the material, although it improves the thermal shock resistance of the product , but the higher thermal conductivity will cause more heat loss in the actual production of cement

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