Prefabricated member for lime rotary kiln and preparation method of prefabricated member

Abstract

The invention discloses a prefabricated member for a lime rotary kiln adopting magnesium-rich magnesium-aluminum spinel waste bricks as main raw materials and a preparation method of the prefabricated member. The invention adopts a technical scheme as follows: the prefabricated member is prepared from the following components in percentage by weight: 35 to 40 percent of 1 to 3 mm magnesium-rich magnesium-aluminum spinel waste bricks, 18 to 25 percent of 0.088 to 1 mm magnesium-rich magnesium-aluminum spinel waste bricks, 30 to 35 percent of magnesium-rich magnesium-aluminum spinel waste bricks less than or equal to 0.088 mm, 3 to 6 percent of silicon nitride fine powder less than or equal to 0.03 mm, 0.05 to 1 percent of metal aluminum powder less than or equal to 0.246 mm, and 4 to 6 percent of composite binding agent; and the added water accounts for 5 to 6 percent of the total weight of the main raw materials; the composite binding agent is prepared from 20 to 40 weight percent of silica powder and 60 to 80 weight percent of aluminate cement, wherein the weight percentage content of SiO2 in the silica powder is more than or equal to 93 percent, and the weight percentage content of Al2O3 in the aluminate cement is more than or equal to 68.75 percent. The preparation method comprises the steps of crushing, screening, grinding, burdening, forming, drying, heat treatment and the like. The prefabricated member adopts the waste bricks as the main raw materials, so that the price is low; and by introducing silicon nitride, the metal aluminum powder and the composite binding agent, the performance and the quality of the prefabricated member can be remarkably improved.

Description

technical field [0001] The invention relates to the field of refractory material industry, in particular to a prefabricated part for a lime rotary kiln and a preparation method thereof. Background technique [0002] At present, the 0-30mm fine-grained grades of domestic limestone mine products usually account for about 30-40% of the total output, and this part of limestone cannot be used to produce active lime by kilns such as sleeve kiln, Maerz kiln, and Phocas kiln. , and the rotary kiln can directly calcinate 0-50mm fine-grained limestone. The construction of a lime rotary kiln production line can not only make full use of limestone mine resources, but also meet the needs of sustainable development of the lime industry. [0003] The inner lining of the lime rotary kiln is mainly built with refractory materials such as high-alumina bricks, clay bricks, magnesia-chrome bricks or magnesia-chrome prefabricated parts and castables. Although the calcination temperature of the ...

AI Technical Summary

Problems solved by technology

Although the calcination temperature of the lime rotary kiln is generally controlled at 1100-1200°C, and the temperature of the gas medium is about 1350°C, during the operation of the rotary kiln, the chromium in the magnesia-chrome material will combine with CaO and a small amount of other materials in the limestone raw material. Alkali metal species react to produce toxic hexavalent chromium compounds (R 2 CrO 4 ), and its generated amount is changed from the initial content in the original product to 0.04×10 -6 Sharply increased to 1000×10 -6 , its concentration value has greatly exceeded the environmental protection standard value

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