Calcium hexaluminate and preparation method thereof

Abstract

The invention discloses a preparation method of calcium hexaluminate. The method includes the following steps that firstly, 40-80 wt% of industrial aluminum oxide powder and 20-60 wt% of aluminate cement are evenly mixed, mixed powder is obtained, the mixed powder is subjected to secondary balling fabrication processing, and green balls are obtained; secondly, after the green balls are dried, the green balls are sintered for 1-5 hours at the temperature of 1650-1800 DEG C, and then the calcium hexaluminate is obtained through smashing and screening. The preparation method of the calcium hexaluminate has the advantages that the technology is simple, cost is low, the production cycle is short, and large-scale industrial production can be achieved. The prepared calcium hexaluminate is high in purity and stable in performance. After the calcium hexaluminate is added into an amorphous fire-resistant material product, the volume density of a fire-resistant material can be effectively reduced, and accordingly the fire-resistant material has the advantages of being good in high-temperature volume stability, heat-preserving and heat-isolation performance, alkali resistance and the like.

Description

technical field [0001] The invention relates to the field of refractory materials, in particular to calcium hexaaluminate and a preparation method thereof. Background technique [0002] Calcium hexaaluminate (CaO·6Al 2 o 3 ), abbreviated as CA6, is an excellent refractory material with a theoretical bulk density of 3.38g / cm 3 , the melting point is as high as 1875°C, it has the characteristics of high refractoriness, low thermal conductivity, excellent alkali resistance, and high stability in reducing atmosphere, and the thermal expansion coefficient of calcium hexaaluminate is very close to that of corundum, and the two can be used together in any proportion , the use of calcium hexaaluminate in amorphous products can effectively reduce the bulk density of the material, endowing it with excellent high temperature volume stability, thermal insulation performance and alkali resistance. [0003] At present, the preparation of calcium hexaaluminate mainly adopts the sinterin...

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Problems solved by technology

The process is complex and the purity of the raw materials is low, that is, the alumina content in the anodic oxidation waste residue of the aluminum profile factory is only 80-90% alumina, and the high impurity content will cause some impurity phases to be generated in the generated calcium hexaaluminate, and then Affect the high temperature performance of the castable

[0008] The current process is a small-batch test process in the laboratory, which is fired in a high-temperature furnace. The production efficiency is low, and most of the raw materials used have high impurity content, which will be accompanied by the production of a large number of impurity phases, which will have a negative impact on the use of calcium hexaaluminate.

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